Guidance

ISOSS HIV report 2022

Updated 22 June 2023

Applies to England

Introduction

The Integrated Screening Outcomes Surveillance Service (ISOSS) carries out the surveillance of pregnancies to women with human immunodeficiency virus (HIV), congenital syphilis and vertically acquired hepatitis B, in England for the NHS Infectious Diseases in Pregnancy Screening (IDPS) programme. HIV reporting has been running since 1989. It was known as the National Surveillance of HIV in Pregnancy and Childhood (NSHPC) until 2018, when ISOSS was established.

This report focuses on pregnancies to women living with HIV who booked for antenatal care in England from 1 January 2020 to 31 December 2020. All HIV screen positive pregnancies reported to ISOSS with data submitted by the end of December 2021 are included; this includes pregnancies to women with established HIV diagnosis as well as those newly diagnosed through antenatal screening. Data presented on vertical transmissions, breastfeeding and trends includes pregnancies reported in previous years.

Previous ISOSS reports (until 2020) covered the whole of the UK and predate current government arrangements. Data reported from 2020 onwards is for England only.

Previous reports presented data based on expected date of delivery year. For this and future reports, data is reported by year of booking for antenatal care to reflect care along the screening pathway. This report uses calendar year in line with the reporting of sexual health data. It is acknowledged that screening programmes publish data by financial year.

IDPS programme standards summary statistics

Screening standards data is submitted by maternity providers with the most recent data relating to screening year 2020 to 2021 (1 April 2020 to 31 March 2021). This data is collected separately from ISOSS surveillance of women with a screen positive result and their infants.

In screening year 2020 to 2021 in England:

• approximately 650,000 pregnant women entered the antenatal screening pathway
• coverage for antenatal HIV, hepatitis B and syphilis screening was 99.8%
• 0.11 eligible pregnant women per 1,000 tested received a new HIV diagnosis

Table 1: trends in screen positive rates for HIV in pregnant women, England, screening year 2017 to 2018 to screening year 2020 to 2021

	2017 to 2018	2018 to 2019	2019 to 2020	2020 to 2021
Returns included/expected	125/147	144/146	140/143	139/142
Screen positive women: rate per 1,000 women tested	1.36	1.26	1.19	0.96
Newly diagnosed women: rate per 1,000 women tested	0.16	0.14	0.13	0.11

Table 1 note 1: known false positive results are not included in the number of screen positives.

Table 1 note 2: the rate for total screen positive women is based on a count that has been rounded to the nearest multiple of 5 for data for 2018 to 2019, 2019 to 2020 and 2020 to 2021, to prevent disclosure by comparison with other published data.

HIV reporting to ISOSS

The process and points in time for data collection can be seen in the data collection processes section. Data is reported to ISOSS by 154 different maternity providers, some of which are part of bigger NHS trusts that report their screening standards data in a combined format that is published in antenatal data standards reports.

In 2020, 100% (616 of 616) of maternity providers in England submitted their initial notifications for women with screen positive results for HIV via the quarterly reporting system on the ISOSS portal, including confirmations from trusts that had no women with screen positive results. Antenatal notification forms were subsequently returned for 99.4% of pregnancies in women living with HIV (established diagnosis and newly diagnosed), and pregnancy outcome forms returned for 99.7% of pregnancies.

HIV overview

There were 607 pregnancies to women with HIV with a booking date in 2020 in England reported to ISOSS. This is a decline from a peak of over 1,400 pregnancies in 2009. Of these, 89.8% (545 out of 607) of women were known to be living with HIV before pregnancy. The remaining women were diagnosed through pregnancy, with the majority (96.8%) as a result of the screening programme. The proportion of women known to have HIV before pregnancy has increased from approximately 40% in the early 2000s (see figure 1).

Figure 1: timing of maternal diagnosis for pregnancies to women living with HIV in England (2000 to 2020)

Figure 1 is a bar chart showing the number of pregnancies in women living with HIV by timing of maternal HIV diagnosis. The proportion of women being diagnosed with HIV during their current pregnancy, as opposed to before pregnancy, shows an overall decrease over time.

Booking date has been collected since 2008 and is a compulsory field since 2020. Prior to this, where a date was not reported, an estimated date had to be used.

Pregnancy management

Women who screened positive for HIV booked for antenatal care by 10+0 weeks gestation in 44.7% of pregnancies, compared to 65.0% in the general population. Women who booked for antenatal care after 20 weeks gestation accounted for 7.4% of pregnancies (see table 2), compared to 5.9% in the general population. (Data from NHS Digital maternity statistics 2020 to 2021). There were 17 women who booked for antenatal care over 30 weeks gestation. One woman received no antenatal care, arriving unbooked in labour. Five women were booked for antenatal care within 7 days of delivery.

Table 2: gestation at booking

Gestation at booking	Number of pregnancies (n=607)	Percentage of pregnancies (%)	General population (%)
Less than 10+0 weeks	271	44.7	65.0
10+0 to 12+6 weeks	183	30.2	20.2
13+0 to 19+6 weeks	108	17.8	8.0
Equal to or more than 20+0 weeks	45	7.4	5.9

Transfers of care

Among women who booked in 2020, 5.3% (32) subsequently transferred their maternity care to another provider. This includes women who unexpectedly delivered at another maternity provider, for example following an in-utero transfer for specialist neonatal services. Between 2009 to 2019, transfer of care occurred in 8.1% of pregnancies. Women who transferred care in pregnancy were more likely to have been born outside the UK, be diagnosed during pregnancy and have a detectable viral load at delivery.

Region of booking

London had the highest number of pregnancies in women living with HIV, accounting for 35.1% of all pregnancies reported. The proportion of pregnancies booked in London have steadily decreased over time, from 46.5% in 2010 and 42.6% in 2015 (statistically significant). The lowest number of pregnancies in women living with HIV was in the South West (see table 3).

Table 3: region of booking

Region of booking	Number of pregnancies (n=607)	Percentage of pregnancies (%)
London	213	35.1
Midlands	115	19.0
East of England	57	9.4
North East and Yorkshire	59	9.7
North West	60	9.9
South West	39	6.4
South East	64	10.6

Maternal demographics

Maternal age

The median age at delivery was 34 years (interquartile range (IQR): 30 to 38 years), with a trend towards increasing maternal age; 1 in 5 of the pregnancies were in women aged 40 or over (see table 4) compared to 1 in 7 pregnancies in 2015. The increasing proportion of pregnancies in women over 40 years of age reflects trends in the general population, with implications for pregnancy management and outcomes (see Townsend C L and others, 2016) including increased risk of stillbirth, gestational diabetes, multiple births and chromosomal conditions.

Table 4: maternal age at delivery

Age group	Number of pregnancies (n=607)	Percentage of pregnancies (%)
Less than 25 years	39	6.4
25 to 29 years	90	14.8
30 to 34 years	173	28.5
35 to 39 years	189	31.1
Equal to or more than 40 years	116	19.1

Ethnic origin

In 2020, 59.1% of pregnancies were in women of black African ethnicity, a decrease from 72.0% in 2015 (see table 5). There has been an increase in the proportion of women from a white background from 18.9% in 2015 to 24.5% in 2020. Most pregnancies (79.2%) were in women born outside of the UK (see table 6), although the proportion of UK-born women increased to 20.8% in 2020 compared to 15.9% in 2015 (see figure 2). There has been a decline in the proportion of pregnancies in women born in sub-Saharan Africa from 72.0% in 2015 to 61.5% in 2020. There is a small but increasing proportion of pregnancies in women from Eastern Europe (4.7% in 2015 compared to 6.5% in 2020). Of women born in Eastern Europe, the most frequently reported countries of birth were Lithuania, Latvia, Romania and Poland.

Of the women who were born outside of the UK, 4.0% arrived in the UK during their pregnancy and a further 10.4% in the year prior to pregnancy (see table 7). Timing of arrival was missing for a number of women (see table 7); ISOSS data collection was amended in 2022 to address this and improve completion. In a recent analysis of ISOSS data (PDF, 1,264KB), pregnant women arriving in the UK were more likely to deliver with a detectable viral load and experience adverse pregnancy outcomes, including low birthweight and preterm delivery.

Table 5: ethnic origin

Ethnicity	Number of pregnancies (n=607)	Percentage of pregnancies (%)
Asian	22	3.6
Black African	359	59.1
Black Caribbean	28	4.6
Mixed	33	5.4
White British	88	14.5
Any other white background	61	10.0
Other	16	2.6

Table 6: maternal world region of birth

World region of birth	Number of pregnancies (n=600)	Percentage of pregnancies (%)
Africa	369	61.5
Asia	25	4.2
Eastern Europe	39	6.5
UK	125	20.8
Rest of Europe	20	3.3
Other	22	3.7

Note on table 6: there were 7 pregnancies where data was not submitted on country of birth.

Figure 2: Maternal region of birth (2000 to 2020)

Figure 2 is a bar chart showing the proportion of pregnancies to women living with HIV by region of birth. The greatest proportion of women continues to be those from sub-Saharan Africa (although the numbers have decreased over time), while the proportion of women from Europe has increased.

Table 7: timing of UK arrival

Timing of UK arrival	Number of pregnancies (n=376)	Percentage of pregnancies (%)
Greater than 5 years before conception	262	69.7
1 to 5 years before conception	60	16.0
Equal to or less than 1 year before conception	39	10.4
During pregnancy	15	4.0

Note on table 7: there were 99 pregnancies where data was not submitted on date of UK arrival.

Parity

Overall, 79.5% of pregnancies were to women who had one or more previous birth (see table 8). However, parity was not completed correctly for 45 women, therefore previous pregnancy history is not known. ISOSS data submission forms were updated in 2022 in response to this.

There was inconsistent reporting of whether the woman was a primigravida (some specifying ‘0’ and others leaving the data point blank), resulting in an update to the online data submission forms. The number of previous livebirths and stillbirths was estimated using the information provided.

Table 8: parity

Parity	Number of pregnancies (n=562)	Percentage of pregnancies (%)
0	115	20.5
1	178	31.7
2 or more	269	47.9

Note on table 8: there were 45 pregnancies with missing information on parity.

Social circumstances

Adverse social factors

Socially complicating issues were reported for 26.8% (148 of 553 where information was available) of women, with multiple issues reported for 66 women. A breakdown of socially complicating issues is shown in table 9. Mental health issues were reported in 10.3% of pregnancies, and housing concerns in 10.1%. These issues are likely to be underreported and only represent those known to healthcare professionals and/or disclosed by women during pregnancy.

Table 9: socially complicating issues

Issue	Number of pregnancies (n=553)	Percentage of pregnancies (%)
Mental health issues	57	10.3
Housing concerns	56	10.1
Social services involvement	51	9.2
Immigration problems	26	4.7
Intimate partner violence	23	4.1
Drug or alcohol misuse	7	1.3
Sex work	2	0.4
Prison	1	0.2
Other	17	3.1

Note on table 9: noteworthy issues in ‘Other’ include not engaging with health services (3), known or suspected female genital mutilation (FGM) (2), disability (2), other type of family abuse (4), financial issues (2), and having no support during pregnancy (3). ‘Not engaging with health services’ and ‘learning difficulties’ were introduced as separate categories from mid-2021 and ‘financial issues’ from 2022. These will be reported on separately in future reports.

Over half of women (55.8%, 275 of 493) were reported as being employed (see table 10). A fifth of women were reported as unemployed (20.7%, 102 of 493) and a fifth were homemakers (20.1%, 99 of 493). Total number in column not equal to total number of pregnancies for adverse social factors

Table 10: employment status in pregnancy

Employment status	Number of pregnancies (n=493)	Percentage of pregnancies (%)
Employed (full or part-time)	275	55.8
Home	99	20.1
Student	15	3.0
Sick	2	0.4
Unemployed	102	20.7

Note on table 10: employment status not reported for 114 women.

For most women, their main support during pregnancy was a cohabiting partner (67.8%, 329 of 485). For 13.0% of women, their main support was a non-cohabiting partner (63 of 485) and for 12.6% it was a family member or friend (61 of 485) (see table 11).

Table 11: main support in pregnancy

Main support	Number of pregnancies (n=485)	Percentage of pregnancies (%)
Partner (cohabiting)	329	67.8
Partner (not cohabiting)	63	13.0
Family or friend	61	12.6
Other	20	0.4
None	30	6.2

Note on table 11: main support not reported for 122 women.

Language

English was spoken by 93.3% of women (502 of 538). Of those who spoke English, this was the first language for 50.0% of women (251 of 502).

Translation services during maternity care were required for 6.1% of women (33 of 538). For those who required translation services, 93.9% (31 of 33) received this through formal interpretation services. There were 2 women who did not receive formal translation services despite requiring them. For one of these women, an interpreter was not available, and for the other woman the reason was not reported. ISOSS does not currently capture language spoken or language required from interpreting services.

Engagement with care

Women with HIV are known to face challenges in engaging in HIV care. ISOSS supported work carried out by the UK Collaborative HIV Cohort (UK CHIC) to further understand this issue (see Okhai H and others, 2021). Findings showed that women with HIV were more likely to continue to engage in HIV care postnatally, when compared with pre-pregnancy. This highlights the importance of the antenatal period to engage women in HIV care, with health benefits for them and their children.

Maternal HIV diagnosis

In 85.9% of pregnancies, women were seen by the screening team within 10 working days of the result being available to maternity services to discuss their screen positive result (see table 12). For 7.1% of women (33), this was more than 20 working days. Where women were not seen within the 10 working days standard, reasons included:

• 10 women did not attend their appointment or would not engage in care
• 7 women experienced delays due to the COVID-19 pandemic
• 2 women were not seen due to staff absence

During the COVID-19 pandemic, technical guidance was issued to providers that results could be given to women virtually rather than face to face within 10 working days. It is recognised that some respondents will have reported that they did not meet the 10-day face to face standard, however they had discussed the positive results with women virtually (for example by phone or online) in the correct timeframe and in line with the guidance.

Table 12: days to screening team appointment from date of screen positive result

Time to being seen	Number of pregnancies (n=461)	Percentage of pregnancies (%)
0 to 10 working days	401	85.9
11 to 15 working days	21	4.5
16 to 20 working days	6	1.3
Greater than 20 working days	33	7.1

Note on table 12: information not available for 146 pregnancies as information collected from June 2020.

Among all pregnancies in women living with HIV, 9 out of 10 women were already aware of their HIV status when they became pregnant (see table 13). Among the women diagnosed during pregnancy, 5 were diagnosed in the third trimester and 2 of the 5 women were diagnosed within 7 days of delivery. One woman had an initial negative screening result at booking and was diagnosed after a repeat test later in pregnancy.

Table 13: timing of maternal diagnosis

Timing of maternal diagnosis	Number of pregnancies (n=607)	Percentage of pregnancies (%)
Before this pregnancy	545	89.8
During this pregnancy	62	10.2

The majority of pregnancies were to women who are thought to have acquired HIV sexually (92.3%) (see table 14). An increasing proportion of pregnancies were to women who themselves acquired HIV vertically (previously known as mother-to-child transmission): 5.6% in 2020 compared to 1.5% in 2015.

Table 14: route of HIV transmission

Route of transmission	Number of pregnancies (n=607)	Percentage of pregnancies (%)
Sexual	472	92.3
Vertical	34	5.6
Injecting drug use	4	0.7
Other	9	1.5

Nearly half of women booking for antenatal care in 2020 were diagnosed through antenatal screening, either in the current pregnancy or a previous pregnancy. This shows the important role of the national screening programme. A third of women were diagnosed in sexual health services (see table 15).

Table 15: setting of diagnosis

Setting of diagnosis	Number of pregnancies (n=499)	Percentage of pregnancies (%)
Antenatal	234	46.9
Sexual health services	155	31.1
General practice (GP)	12	2.4
Other hospital department	43	8.6
Tested abroad	47	9.4
Other	4	1.6

Note on table 15: there were 108 pregnancies where data was not submitted on setting of diagnosis.

Spotlight on women diagnosed during pregnancy

A recent ISOSS analysis looking at data between 2010 and 2019 (PDF, 578KB) found that among women diagnosed with HIV during pregnancy, the median gestational age at diagnosis significantly declined from 13 weeks (IQR 10 to 17 weeks) in 2010 to 12 weeks (IQR 9 to 16 weeks) in 2019. Findings also showed that median gestational age at antiretroviral therapy (ART) initiation declined from 21 weeks in 2010 (IQR 19 to 25 weeks) to 16 weeks in 2019 (IQR 13 to 20 weeks), which was also statistically significant. These trends reflect improved care pathways and changes in clinical guidelines.

In response to themes identified in the HIV vertical transmission clinical expert review panels (CERPs), data is now collected on whether women had a screen negative result earlier in pregnancy. The British HIV Association (BHIVA) standard for newly diagnosed women being seen by specialist HIV services is within 2 weeks of diagnosis. See the BHIVA Standards of Care 2018. This standard will be reported in future reports.

Spotlight on pregnancies to women with vertically acquired HIV

Between 2006 and 2021, there were 202 pregnancies in 131 women living with vertically acquired HIV. There was a 10-fold increase in pregnancies in this group over the time period from 0.3% of reported pregnancies in 2006 to 2009, to 3.0% in 2018 to 2021. Concurrent paediatric and maternity reporting provide a unique opportunity to link historical paediatric reports of women diagnosed as children and seen for paediatric care in the UK to later pregnancy reports in ISOSS. Long-term follow-up of children living with HIV is carried out by the Children’s HIV and AIDS Reporting System (CHARS).

The median age at paediatric diagnosis was 6 years of age (IQR: 2 to 11 years), with 22 of 131 women diagnosed under 1 year of age. There were 81 of 131 women (61.8%) diagnosed as children in the UK, and 85.5% of women were reported to ISOSS in childhood as part of the paediatric surveillance.

Overall, 17.6% of these women (23 of 131) had a history of an AIDS-defining illness and 12 of 23 had an AIDS-defining illness at diagnosis.

Pregnancy outcomes showed higher rates of termination of pregnancy (8.9%) and stillbirth (2.0%) compared to women with heterosexually acquired HIV (2.3% and 0.8% respectively). Median age at delivery was 24 years (IQR: 21 to 27 years) for women with vertically acquired HIV compared to 33 years (IQR: 29 to 37 years) for those with sexually acquired HIV.

Women with vertically acquired HIV tended to book earlier than those with sexually acquired HIV (76.0% booked before 13 weeks, compared to 64.0%), and a higher proportion were on ART at conception (80.8% vs 56.2%), statistically significant. A first CD4 count in pregnancy of over 500 cells per millilitre (35.0% vs 4.6%) was seen in a lower proportion of women with vertically acquired HIV, with fewer women delivering with an undetectable viral load (78.7% vs 83.9%); both of these differences were statistically significant. This supports previous findings using national surveillance data in the UK (see Byrne L and others, 2017). Preterm delivery was more common among women with vertically acquired HIV (18.4% vs 12.5%); this was statistically significant.

ART and clinical management in pregnancy

Women were on ART in 99.2% of pregnancies, with 83.7% of women conceiving on ART (see table 16), an increase from 70.6% in 2015. Between 2008 and 2018, patterns of ART use changed, particularly the use of third agents (see Rasi V and others, 2022). The most frequently used protease inhibitor changed from lopinavir to darunavir and use of integrase inhibitors increased steadily over this period. These trends reflect changes in BHIVA pregnancy guidelines, as new agents and new combinations and classes became available.

Table 16: timing of ART in pregnancy

Timing of ART	Number of pregnancies (n=601)	Percentage of pregnancies (%)
Prior to pregnancy	503	83.7
First trimester	16	2.7
Second trimester	72	12.0
Third trimester	5	0.8
No treatment	5	0.8

Table 16 note 1: there were 3 pregnancies with missing information for timing of ART and 3 pregnancies missing any information on ART.

Table 16 note 2: those not on treatment included women who declined treatment, miscarried before treatment commenced, went abroad before treatment could have commenced, or delivered before treatment commenced.

Figure 3: timing of maternal diagnosis and ART at conception, 2011 to 2020

Figure 3 is a bar chart showing the number of pregnancies in women living with HIV from 2011 to 2020. It shows the proportions each year of women diagnosed with HIV and on ART at conception, diagnosed with HIV and not on ART at conception, and diagnosed antenatally. It also shows an ‘other’ category, which represents pregnancies lacking information on the timing of diagnosis or ART use. The data shows that the number of women with a prior diagnosis conceiving on ART has been steadily increasing over time.

Clinical characteristics

A normal CD4 count is considered over 500 cells per µl. When a CD4 count falls below 200 cells per µl, there is a high risk of opportunistic infections and other serious conditions. The BHIVA recommendation in the guidelines for the management of HIV in pregnancy and postpartum (2018) is that CD4 is taken at baseline (earliest point in pregnancy) and at the point of delivery.

First CD4 count in pregnancy was over 500 cells per µl in 58.5% of pregnancies, increasing from 54.4% in 2015. The proportion of pregnant women with a CD4 count under 200 cells per µl was 7.7% in 2020 compared to 6.4% in 2015 (see table 17) but differences were not significant. CD4 count was not reported for 110 of 607 (18.1%) of pregnancies.

First pregnancy viral load was undetectable (equal to or less than 50 copies per ml) in 87.0% of pregnancies to women diagnosed before pregnancy. This reflects the high proportion of women already on ART at conception. Of the 69 women diagnosed before pregnancy with a detectable first pregnancy viral load, 46 were already on ART. High viral load in pregnancy is linked with increased risk of vertical transmission and maintaining a low viral load in pregnancy is known to improve outcomes for both women and infants. This illustrates the need for maternity providers to promptly refer all women living with HIV to specialist services for appropriate management and treatment.

Table 17: first CD4 count in pregnancy

First CD4 count in pregnancy (cells per µl)	Number of pregnancies (n=497)	Percentage of pregnancies (%)
Equal to or more than 500	290	58.5
350 to 499	111	22.3
200 to 349	58	11.7
Less than 200	38	7.7

Note on table 17: CD4 count missing for 110 pregnancies.

Table 18: first viral load in pregnancy (women diagnosed before pregnancy)

First viral load in pregnancy (copies per ml)	Number of pregnancies (n=529)	Percentage of pregnancies (%)
Equal to or less than 50	460	87.0
51 to 399	33	6.2
400 to 999	7	1.3
1,000 to 9,999	17	3.2
Equal to or more than 10,000	12	2.3

Note on table 18: viral load in pregnancy missing for 16 pregnancies.

Comorbidities

A coinfection of syphilis, hepatitis B or hepatitis C was reported in 7.1% of pregnancies, with more than one coinfection reported in some pregnancies (see table 19). Other coinfections reported included Group B strep, herpes simplex virus, chlamydia and tuberculosis (TB).

Table 19: coinfections

Coinfections in pregnancy	Number of pregnancies (n=607)	Percentage of pregnancies (%)
Syphilis	9	1.5
Hepatitis B	26	4.3
Hepatitis C	8	1.3

Note on table 19: column total (number of pregnancies) not equal to total number of coinfections listed

Pregnancy outcomes

Among the 607 pregnancies in women living with HIV booking in 2020, 540 (89.0%) resulted in the livebirths of 553 babies (including 12 multiple births), and 1 (0.1%) stillbirth (see table 21). Between 2015 and 2020, there were 35 stillbirths that occurred among 4,574 births (outcome at 24 weeks and above gestation), with a stillbirth rate of 7.65 per 1,000 livebirths (95% confidence interval (CI): 5.33 to 10.63).

Table 20: outcome per pregnancy

Pregnancy outcome	Number of pregnancies (n=607)	Percentage of pregnancies (%)
Livebirth	540	89.0
Stillbirth	1	0.1
Miscarriage	41	6.8
Termination	8	1.3
Left UK before delivery	7	1.2
Lost to follow-up before delivery	1	0.2

The proportion of women delivering vaginally has remained stable since 2015, with nearly half of deliveries being vaginal, in line with the BHIVA pregnancy guidelines (see figure 4 and table 21).

Figure 4: mode of delivery among women diagnosed with HIV (2000 to 2020)

The area chart in figure 4 shows that vaginal births have steadily increased since 2003. Elective caesarean sections decreased between 2001 and 2014, and have remained fairly stable since. Emergency caesarean sections have remained stable since 2000.

Table 21: mode of delivery

Mode of delivery	Number of births (n=539)	Percentage of births (%)	Percentage of births in the general population (2020 to 2021) (NHS Digital maternity statistics)
Vaginal	258	47.9	64.5
Elective caesarean	149	27.6	14.6
Emergency caesarean	132	24.5	18.9

Note on table 21: there were 2 births missing information on mode of delivery.

Figures in table 21 are for pregnancies resulting in livebirth and stillbirth. Multiple births are counted once (per pregnancy, not per infant) in this table.

Viral load at delivery

Women delivered with an undetectable viral load (equal to or less than 50 copies per ml) in 93.4% of pregnancies (viral load within 30 days before delivery or 7 days after delivery) (see table 22). This reflects the high coverage of ART in pregnancy (table 16). Of the 6 women delivering with a viral load of over 400 copies per ml, the range was 2,240 to over 1 million. These were complex cases and included women who had adherence issues, accessed antenatal care late in pregnancy or who presented in labour unbooked.

Viral load at delivery data was not available for 15.5% of deliveries. The reason for no viral load being available at delivery is now requested from providers. BHIVA guidelines state that maternal viral load should be monitored at 36 weeks and delivery to inform decisions around mode of delivery, additional ART in late pregnancy and during delivery, and management of the infant.

Maternity providers are now asked to indicate (with details) if they were aware of any concerns regarding viral load during the pregnancy, including timing of any detectable viral load measurements.

Table 22: viral load at delivery

Viral load	Number of pregnancies (n=457)	Percentage of pregnancies (%)
Equal to or less than 50 copies per ml	427	93.4
51 to 399 copies per ml	24	5.3
Equal to or more than 400 copies per ml	6	1.3

Note on table 22: viral load within 30 days of delivery (30 days prior to delivery or 7 days after). There were 84 births with missing information on viral load within 30 days of delivery.

ART at delivery

Additional ART during labour and delivery was given in 3.2% of pregnancies (16 of 498, missing information for 43 pregnancies). Some of the reported issues were:

• 10 women had detectable viral load at delivery
• 2 women had no viral load within 30 days of delivery
• 2 women had issues with medication adherence

Additional ART given was:

• intravenous azidothymidine (IV AZT) in 10 pregnancies
• IV AZT and nevirapine in 2 pregnancies
• other ART including nevirapine (1 pregnancy), IV AZT, nevirapine and tenofovir (1 pregnancy), IV AZT, nevirapine and raltegravir (1 pregnancy) and IV AZT and dolutegravir (1 pregnancy)

Obstetric complications

ISOSS data collection forms specifically ask if the woman had pre-eclampsia or gestational diabetes on the pregnancy outcome form. Respondents are also able to report any other complicating obstetric issues in the pregnancy. Pre-eclampsia was reported in 5.8% of deliveries, increasing from 4.0% in 2015. Gestational diabetes was reported in 12.1% of deliveries, increasing from 5.1% in 2015 (see table 23). From mid-2021, ISOSS began collecting the women’s height and weight at booking, which will allow greater insights into work on obstetric complications and associated risk factors.

Table 23: obstetric complications

Pregnancy complication	Number of deliveries (n=531)	Percentage of pregnancies (%)
Pre-eclampsia	31	5.8
Gestational diabetes	64	12.1

Note on table 23: there were 10 deliveries missing information on pregnancy complications.

Infant outcomes

Preterm delivery (less than 37 weeks gestation) occurred in 12.3% of deliveries, with 6.1% occurring under 34 weeks gestation (table 24). Among preterm deliveries, median gestation at delivery was 34.5 weeks (IQR: 31.5 to 36.0 weeks). The preterm delivery rate for women living with HIV has declined from 14.9% in 2019 (see the 2021 ISOSS HIV report). The preterm delivery rate in the general population for 2020 (as shown in ONS birth statistics for 2020) was 7.7%. The proportion of infants born to women living with HIV with a low birthweight (less than 2.5kg) was 14.2%, with 2.9% born weighing less than 1.5kg (very low birthweight) (table 25).

Table 24: gestational age at delivery

Gestational age	Number of births (n=554)	Percentage of births (%)	Percentage of births in general population (England) (ONS birth statistics 2020)
Equal to or more than 37 weeks	485	87.7	92.3
Less than 37 weeks	68	12.3	7.7

Note on table 24: the number of births includes one stillbirth.

Table 25: birthweight

Birthweight	Number of births (n=549)	Percentage of births (%)	Percentage of births in general population (England) (ONS birth statistics 2020)
Equal to or more than 2.5 kg	472	86.0	93.3
1.5 to 2.4 kg	61	11.1	6.0
Less than 1.5 kg	25	2.9	0.8

Note on table 25: there were 4 infants with missing information on birthweight.

Among livebirths and stillbirths, 24 out of 553 (4.3%, 95% CI: 2.8% to 6.4%) had reported congenital conditions using the International Statistical Classification of Diseases and Related Health Problems 10th Revision (see table 26). Among these, 6 had multiple conditions reported. Conditions reported included trisomies 18 and 21, heart defects and extra digits. Two livebirths (0.4%) resulted in a neonatal death within 28 days of birth.

In an analysis using ISOSS data (see Yan H, Peters H and Thorne C, 2022) among over 20,000 livebirths between 1998 and 2017, the overall neonatal death rate was 4.1 per 1,000 livebirths, higher than the general population (3.2 per 1,000). Prematurity was the leading cause of death, followed by congenital condition. Detectable viral load was significantly associated with increased risk, and ART use at conception with decreased risk of neonatal death. A collaboration with Mothers and Babies Reducing Risk by Audits and Confidential Enquiries (MBRRACE-UK) will look further at stillbirths, neonatal deaths and maternal deaths where one or more of the 3 screened for infections was present.

Table 26: congenital conditions

Congenital conditions reported	Number of deliveries (n=553)	Percentage of deliveries (%)
Conditions reported	24	4.3
None reported	650	95.7

HIV and breastfeeding

BHIVA recommends formula-feeding for infants born to women living with HIV, eliminating the risk of postnatal transmission. Since 2012, the BHIVA guidelines also state:

Women who are virologically suppressed on combination ART with good adherence and who choose to breastfeed should be supported to do so, but should be informed about the low risk of transmission of HIV through breastfeeding in this situation and the requirement for extra maternal and infant clinical monitoring

Guidelines include monthly testing for the woman and infant during the period of breastfeeding, and advice to breastfeed for as short a time as possible (no longer than 6 months).

This guidance was updated during the COVID-19 pandemic in March 2020, stating that breastfeeding should be discouraged as it requires monthly maternal and infant viral load follow-up for the duration of the breastfeeding period and for 2 months post-cessation of breastfeeding. This was the case until September 2021.

ISOSS has collected data on planned and actual supported breastfeeding among women living with HIV who choose to breastfeed in line with BHIVA guidelines since 2012. Cumulative data from 2012 onwards on supported breastfeeding in the UK is presented.

Planned mode of feeding

Since 2012, there have been 267 reports (3.1%) of breastfeeding or intention to breastfeed among 8,526 deliveries. There has been an increase over time in reports of planned and/or actual supported breastfeeding (see figure 5). ISOSS collects the reasons reported for the woman wanting to breastfeed (see table 27). Bonding and health benefits were the most common reasons given (68.7% and 59.6% respectively).

Figure 5: reports of planned and/or actual supported breastfeeding to women living with HIV by delivery year

Figure 5 is a bar chart showing the number of infants born to women living with HIV who were supported to breastfeed, showing the proportions of women who were reported to be breastfeeding via paediatric follow-up, reported not to be breastfeeding via paediatric follow-up, or who reported an intention to breastfeed at booking and/or delivery but breastfeeding status was not confirmed by paediatric reporting.

Figures from 2012 to 2020 show the majority of women were confirmed as breastfeeding via paediatric follow-up. Since 2019, increased numbers of cases have only been reported as intending to breastfeed, with breastfeeding status as yet unconfirmed by paediatric reporting. This accounts for the majority of women in 2021.

Three infants born in 2019 confirmed breastfed via paediatric follow-up were reported only via paediatric scheme (no maternity report). It is unclear if the woman had discussed or disclosed her intention to breastfeed during her pregnancy, or if this is a reporting oversight by the maternity provider.

Table 27: reasons for breastfeeding

Reason for breastfeeding (as reported by clinical respondent)	Number of pregnancies with reason reported	Percentage of pregnancies with reason reported (%)
Bonding	158	68.7
Health benefits	137	59.6
Family or friends’ expectations or pressure	51	22.2
Disclosure concerns	60	26.1
Previously breastfed since diagnosis	59	25.7
Previously breastfed before diagnosis	32	13.9
Concerns about finance	6	2.6
Other or additional reason	30	13.0

Note on table 27: some women had multiple reasons for wanting to breastfeed.

In 37 of 267 pregnancies the reasons for wanting to breastfeed was not completed or not known.

Among women planning to breastfeed, partners were not aware of the woman’s HIV status in 16.0% of cases, and GPs were unaware in 7.0%.

Confirmed breastfeeding

Among women planning to breastfeed, 203 were confirmed to have breastfed using linked paediatric reports of supported breastfeeding by March 2022. Of note, 42 women were reported to have started breastfeeding during the application of the interim BHIVA guidelines where breastfeeding was not recommended during the pandemic.

Most instances of supported breastfeeding (94.5%) were by women known to be living with HIV before pregnancy (see table 28). Women who were born abroad make up 84.0% (170) of supported breastfeeding reports, with the majority born in sub-Saharan Africa (see table 29), with 34.8% from Nigeria and 28.0% from Zimbabwe. The majority of women (81.5%) were black African and 11.0% were white (see table 30). The median age of these women at delivery was 35 years (IQR: 31 to 40 years).

Where reported, 80.2% (77 of 96) of women and infants had monthly testing arranged in line with BHIVA guidelines. In 11.6% of cases (11 of 96), monthly testing was not arranged for a variety of reasons: in the case of one provider there were communication issues with paediatric scheduling (5); in other cases, reasons included parental request for no additional paediatric testing and the woman being long-term virologically suppressed (in line with BHIVA guidelines, all women supported to breastfeed should receive monthly testing along with their infants, regardless of virological suppression). In the remaining 8 cases, monthly testing was not applicable as duration of breastfeeding was less than 2 months.

Attendance issues for maternal and infant testing were reported for a quarter of mother-infant pairs (25 of 96) where women did not attend their own appointments or appointments for their infants.

Table 28: timing of diagnosis for women living with HIV who breastfed their babies

Timing of diagnosis	Number of pregnancies (n=201)	Percentage of pregnancies (%)
Before pregnancy	190	94.5
During pregnancy	11	5.5

Note on table 28: there were 2 pregnancies with missing information on maternal timing of diagnosis.

Table 29: region of birth for women living with HIV who breastfed their babies

Maternal place of birth	Number of pregnancies (n=201)	Percentage of pregnancies (%)
UK	31	16.0
Abroad	170	84.0

Note on table 29: there were 2 pregnancies with missing information on maternal place of birth.

Table 30: ethnicity of women living with HIV who breastfed their babies

Maternal ethnicity	Number of pregnancies (n=200)	Percentage of pregnancies (%)
Black African	163	81.5
Black Caribbean	5	2.5
White	22	11.0
Other	10	5.0

Note on table 30: there were 3 pregnancies with missing information on maternal ethnicity.

Outcome: feeding patterns and follow-up status of infants

Breastfeeding was reported to have stopped for 150 out of 203 infants. In all other cases, either breastfeeding was still ongoing or notification of cessation of breastfeeding had not yet been received.

Among those confirmed to have stopped breastfeeding, the total duration of breastfeeding ranged from one day to 2.3 years, with a median duration of 56 days (IQR: 23 to 140 days). Overall, 18.7% (28 of 150) of infants were breastfed for 7 days or under, and 93.3% (140 of 150) breastfed for 6 months or under.

In most instances (127 of 150, 84.7%), formula was introduced at the point of stopping breastfeeding, with the primary reason for switching to formula feeding reported as:

• part of a plan to stop breastfeeding (65 of 127)
• maternal viral load rebound (9 of 127)
• mastitis (5 of 127)
• weaning (4 of 127)
• other reasons (44 of 127), including latching problems or difficulty establishing breastfeeding, cracked nipples, failure to thrive, or finding breastfeeding challenging

For 10 infants (6.7%), breastfeeding continued after the introduction of formula (the duration of mixed feeding with formula milk in these cases was not known). For a further 10 infants, breastfeeding status following introduction of formula was unknown.

Table 31 below summarises infant follow-up status where breastfeeding was known to have stopped.

Table 31: follow-up status of supported breastfed infants where breastfeeding had stopped

Follow-up status	Number of pregnancies (n=150)	Percentage of pregnancies (%)
Negative 18 to 24 month antibody test	106	70.7
Discharged before 18 to 24 month antibody test	5	3.3
Still in follow-up	34	22.7
Lost to follow-up	4	2.7
Declined testing	1	0.7

To date, there have been no transmissions among infants breastfed when BHIVA guidance was followed, with 106 of 150 (70.7%) reported to have a negative 18 to 24 month antibody test. The infection status for the remaining 29.3% could not be determined based on their 18 to 24 month antibody test, as the majority of these infants are still being followed up.

It is important to note that a number of vertical transmissions are attributed to breastfeeding, where clinicians were told the woman intended to formula feed, who may have been eligible for supported breastfeeding.

Vertical transmissions

Vertical transmission is the passage of a pathogen or infection from woman to infant during pregnancy, at birth or through breastfeeding.

The HIV vertical transmission rate is presented in 2-year intervals for infants born 2 years prior to the year this report is published. This accommodates the confirmatory antibody test used to establish infant infection status at 18 to 24 months of age.

Figure 6: vertical transmission rate by year of birth for infants born to diagnosed women in England

Figure 6 shows the vertical transmission rate for England only. The data is presented in 2 yearly intervals to reduce the risk of disclosure. The vertical transmission rate has been below 0.4% in England since 2012, reducing from 2.86% in 2000 to 2001.

Previously, ISOSS reported the vertical transmission rate for the UK, however from 2020 the service became England-only due to governance arrangements. The data in the figure has been calculated to show England vertical transmission data over the last 20 years. This graph can be compared to the 2021 ISOSS HIV report, which shows the UK transmission rate up to 2019.

There were 3 known vertical transmissions among 1,205 infants born in the calendar years 2018 and 2019 where infection status is known, with a vertical transmission rate of 0.25% (95% CI 0.05% to 0.73%).

Infant follow-up

Clinical care

Among infants born in 2018 and 2019 to women diagnosed with HIV, with paediatric follow-up reported to ISOSS, 99.5% of infants (1,271 of 1,277) were given antiretroviral prophylaxis after birth. This information was not reported for 6 infants. Where duration of prophylactic treatment was available, 24.7% of infants (184 of 744) received this for 2 weeks, 73.9% (550 of 744) for 4 weeks and 10 infants for 6 weeks.

Neonatal conditions or complications were reported in 12.1% of infants (152 of 1,258). These included:

• 18 infants with heart and circulatory issues
• 33 infants with intrauterine growth restriction and/or preterm delivery
• 8 infants with gastrointestinal issues
• 6 infants with musculoskeletal issues
• 7 infants with respiratory issues

Infant testing and infection status

BHIVA guidelines recommend that all infants exposed to HIV are followed up until age 18 to 24 months for antibody testing for seroconversion. Guidelines were updated in 2020 to recommend that infants should receive confirmatory antibody testing at 22 to 24 months of age. Challenges around the monitoring of vertical transmissions, including infants discharged based on earlier negative antibody have previously been discussed in the ISOSS 2021 HIV report.

Among 1,277 infants born in the 2-year period 2018 and 2019 with paediatric follow-up reported, 1,299 were uninfected. Of these:

• 808 of 1,299 were reported as uninfected based on 18 to 24 month antibody test
• 421 of 1,299 were reported to have a negative PCR and/or antibody under 18 months

Of the 421 infants not reported to have an 18 to 24 month antibody test:

• 83 were lost to follow-up before 18 months
• 44 were discharged before 18 to 24 months
• 2 died (see below)
• 292 children are missing a final report to ISOSS to confirm discharge status

A further 48 of 1,277 infants only had a birth PCR:

• 34 were still in follow-up
• 2 died (see below)
• 12 were lost to follow-up

Four infants died before 18 to 24 month confirmatory antibody testing, 3 from complications arising from prematurity and one from a congenital condition (all infants had negative PCRs from birth).

HIV vertical transmission clinical expert review panel (CERP)

All children diagnosed with HIV and seen for paediatric care in England are reported to ISOSS. This includes children who have acquired HIV vertically. These children are born to women who are either:

• known to be living with HIV during pregnancy (captured in the ISOSS maternity surveillance)
• diagnosed after their pregnancy (not known to ISOSS maternity surveillance)

Additional data collections take place for all HIV vertical transmissions in England, producing anonymised care summaries to be reviewed by the CERP. Detailed anonymised reports are taken to the IDPS HIV CERP. The panel consists of relevant clinical specialists, including the IDPS screening programme, maternity, laboratory, paediatrics, sexual health services and other clinical specialists.

The purpose of the panel is to:

• establish the circumstances surrounding the transmission
• identify any contributing factors and learning points
• feed recommendations into the IDPS advisory group to inform national guidelines and policy

Figure 7: all reported vertical transmissions (2006 to 2021) by timing of maternal diagnosis and year of birth (n=156)

Figure 7 shows all 156 vertical transmissions reported to ISOSS to date. Note that reporting may occur years after birth – 108 transmissions were reported by 2014, 35 were reported between 2014 and 2020 and 13 were reported between 2020 and 2021.

The recent CERPs have covered 13 vertical transmissions reported between June 2020 and the end of December 2021, with data collection complete by December 2021. The years of birth for the children ranged from 2008 to 2021.

There were 13 children born to 13 women where vertical transmission occurred. Of these 13 children:

• 6 were born to women diagnosed before pregnancy
• 1 was born to a woman diagnosed during pregnancy
• 6 were born to women diagnosed after pregnancy

Among the 6 women diagnosed before pregnancy, 4 were on ART at conception. However, all still had detectable viral load at booking (range: 75 to 1,270 copies per ml).

The majority (12 of 13) of children were born to women who were born outside the UK. Of these, 8 were from sub-Saharan Africa and 4 from Eastern Europe. Region of birth was not reported for one woman. Time in the UK before delivery ranged from 2 weeks to 19 years (median time 8 years).

Median maternal age at delivery was 34 years (IQR: 31 years to 39 years). The highest number of vertical transmissions were seen in London (6 of 13) (see table 32). Seven women booked for care in England by 13 weeks gestation, 3 between 13 and 20 weeks gestation, and 3 after 20 weeks gestation.

Table 32: region of child’s birth

Region of child’s birth	Number of children	Percentage of children (%)	Cumulative number of children since 2014 (n=44)	Percentage of children (%)
London	6	46.2	21	47.7
Midlands	2	15.4	6	13.6
East of England	2	15.4	5	11.4
North East and Yorkshire	2	15.4	5	11.4
North West	0	0	3	6.8
South West	1	7.7	2	4.5
South East	0	0	2	4.5

Note on table 32: reporting from Wales, Scotland and Northern Ireland ceased in 2019. However, 4 transmissions were included in previous CERPs between 2014 and 2019.

Numbers may not equal 100% due to rounding.

Complicating issues

In over half of transmissions (7 out of 13), there were complicating issues reported at the time of pregnancy that are thought to have contributed to the vertical transmission. These numbers are likely to be under reported as they are based on information clinicians had available at the time of the pregnancy. Significant inequalities and barriers to care were identified. Table 33 shows a breakdown of the complicating issues reported.

Table 33: complicating issues reported in cases of vertical transmission

Complicating issues reported	Number of transmissions	Cumulative number of transmissions since 2014 (n=48)
Safeguarding	4	9
Mental health diagnosis	3	12
Housing issues	3	12
Drug or alcohol misuse	0	3
Intimate partner violence	0	5
Uncertain immigration status	2	7
Financial issues	0	4
Translation required	2	3
Any reported	7	26

Table 33 note 1: a woman may have had more than one complicating issue reported at the time of pregnancy.

Table 33 note 2: translation required row: formal translation services were provided where comprehension and/or fluency in English were complicating issues.

Child outcomes

Age at diagnosis for these 13 children ranged from birth to 7 years. Among those born to women diagnosed by delivery, there were 4 infants who tested PCR positive at birth and so are likely to have acquired HIV in utero.

Five of the 13 children had clinical indications at diagnosis, including:

• oral thrush
• liver problems
• pneumocystis pneumonia (PCP) at diagnosis

Of these 5 children, 4 were born to women who were unaware of their HIV status by delivery.

For one child, there was a delay of testing and diagnosis due to emotional distress relating to the woman’s own recent diagnosis and death of the child’s father.

Contributing factors

CERPs have taken place to discuss these vertical transmissions. The main factors thought to have contributed to the transmission, as identified by the group, are shown below along with additional contributing factors.

Main contributing factors to vertical transmission (1 factor per transmission)

The main contributing factors identified included:

• seroconversion following a confirmed negative antenatal HIV test (6)
• issues with adherence to treatment (3)
• breastfeeding where clinicians were unaware (1)
• booking at more than 20 weeks gestation or unbooked for antenatal care (1)
• no specific contributing factors (2)

In 6 vertical transmissions, the woman had a negative HIV test in pregnancy, and then acquired HIV seroconverting at some point during pregnancy or in the postnatal period while breastfeeding.

Among the 6 women who seroconverted:

• 1 woman was rescreened late in pregnancy following her partner’s diagnosis
• 3 women (and their partners) were tested following the symptomatic diagnosis of the child
• 2 women were tested following their partner’s diagnosis, which led to the child being tested

Three transmissions were in women with issues around adherence to ART and/or engagement with healthcare services in pregnancy. All 3 women were diagnosed before pregnancy. One woman declined treatment in pregnancy and did not engage with healthcare services, one had issues tolerating ART and one had difficulties remembering to take ART regularly. All had mental health issues diagnosed and were receiving involvement from social services. Viral loads and delivery ranged from 13,000 to 395,000 copies per ml.

One woman had received no antenatal care in England and was screened in labour with the result being available 5 days after delivery. No treatment was given before the baby was born and breastfeeding had been initiated.

For one infant, the transmission was postnatal and likely due to breastfeeding, with clinicians being unaware of the woman’s feeding choice. This woman had been supported to breastfeed in a previous pregnancy but was advised against breastfeeding due to having a detectable viral load in this pregnancy. There were issues with engagement with healthcare services reported in the pregnancy where the transmission occurred.

Recommendations and progress

Below are the themes identified by members of the CERP in the above-mentioned vertical transmission reviews.

Urgent screening

Women presenting unbooked in labour made up a significant proportion of the occurrences where infants were found to have congenital syphilis (see ISOSS report for syphilis) and was also seen in one vertical transmission of HIV. In both syphilis and HIV cases, although screening samples were taken from women in labour, the urgency of the test was not always appropriately communicated to laboratory staff, results were not followed up, screening teams were not informed, and women and infants were discharged without results being available. This resulted in delayed diagnosis and treatment for both the woman and infant and, in some cases, women being uncontactable following discharge to discuss the results.

Women presenting in labour unbooked having received no antenatal care often have unique and challenging social issues and are a particularly vulnerable group. The recently updated IDPS programme’s laboratory handbook provides guidance on the management of urgent screening results for women in labour, or who are likely to deliver before confirmed results can be issued.

Negative now and seroconversion

As in the ISOSS 2021 HIV report, 6 children were found to have acquired HIV despite the women having a screen negative result early in pregnancy. This means the women seroconverted during pregnancy or in the postnatal period while breastfeeding. The importance of women understanding that they were negative at the time the sample was taken was highlighted again. Women should have this and the potential risks for becoming HIV positive explained to them when receiving their negative results.

Multidisciplinary team (MDT) meetings

The lack of a well-functioning and well-represented MDT was seen again. Children with vertically acquired HIV were found where healthcare services were aware of maternal infection antenatally but care plans were not in place prior to delivery, or guidelines and care plans were not followed after delivery. In some areas where infection rates are low, joint or regional MDTs had been implemented (for example, North London Regional Network), allowing clinicians to access support for the care of women and their infants.

Risk of transmission in pregnancy and while breastfeeding

The undetectable equals untransmittable (U=U) statement applies only to sexual transmission of HIV. Messaging out about U=U in pregnancy and while breastfeeding being not applicable should be stressed by the screening programme (potentially in the handbook and e-learning). This issue is already highlighted by BHIVA.

Continuity of care

It is important to acknowledge the role and impact that continuity of care or expertise provided by screening midwives or nurses and infectious diseases specialists can have on this vulnerable population who often face many health inequalities. The difference made by providing continuity of care to women who screen positive for any of the 3 infections covered by the IDPS programme was evident in both the HIV and syphilis CERPs.

The importance of improving care for vulnerable groups has been highlighted by NHS England. Core20PLUS5 is a national approach to support the reduction of health inequalities at both national and system level. The approach defines a target population cohort – the ‘Core20PLUS5’ – and identifies 5 focus clinical areas requiring accelerated improvement. One of these areas is around maternity care ‘ensuring continuity of care for 75% of women from black, Asian and minority ethnic communities and from the most deprived groups’.

It also puts a focus on inclusion health groups, which includes:

• people experiencing homelessness
• drug and alcohol dependence
• vulnerable migrants
• Gypsy, Roma and Traveller communities
• sex workers
• people in contact with the justice system
• victims of modern slavery
• other socially excluded groups

Education and shared learning

Building on the previous recommendation of raising awareness of vertically acquired infections, the issue of shared learning from the vertical transmission reviews was highlighted by CERP members. Maternity providers involved with the reviews reported a desire to receive feedback from the CERP. There were discussions around potential education events and the use of anonymised case scenarios, to support raising awareness and improving care.

New recommendation for the screening programme

The IDPS team will develop ways of feeding back to providers who report infants with vertically acquired HIV following the CERP reviews, along with wider learning opportunities for maternity, paediatric and sexual health services.

Recommendations: progress and new recommendations

Progress update

Recommendation 1

Information should be available for women and their partners about protecting themselves from infections in pregnancy, and sexual health advice. This should include how to access sexual health services.

Progress

Promote discussion at booking among maternity staff via screening leads (to be communicated during syphilis quality improvement project workshops and in the next e-learning update).

Recommendations 2, 3, 4 and 5

Promote the ‘negative now’ message to all women following a negative screening test result.

Strengthen and promote guidelines for healthcare staff to increase targeted retesting following the identification of women who may have been exposed to risk, including those who:

• change their sexual partner
• inject drugs
• are a sex worker
• have an infected partner
• have a partner who is sexually active with another person
• are diagnosed with an STI

Referral should be made to sexual health services for testing for women presenting with suspected or confirmed sexually transmitted infections (STIs) in pregnancy, in line with BASHH guidelines.

Refer all women who disclose that their sexual partner has current STIs or is HIV positive to sexual health services.

Progress

These recommendations have been acted on by:

• inclusion in the current IDPS programme handbook update, which is in progress
• an update to the laboratory handbook to include the ‘negative now’ message being added to laboratory reports
• plans to raise awareness as part of the IDPS syphilis quality improvement project, for example via maternity provider workshops
• strengthening the message in the next update of the elearning for healthcare (elfh) IDPS online training module

Recommendations 6 and 7

Strengthen the importance of having a clinically representative MDT for screen positive women in guidance. This may include promoting involvement of the wider health and social care team, as appropriate to the individual needs of the woman.

Strengthen the importance of MDT working and communication to ensure that care plans for women and their babies are available in the womens’ notes and are accessible by paediatricians in advance of the baby being born.

Progress

Additional information on what is meant by MDT, including suggested membership and ways of working to be included in the IDPS programme handbook update.

Recommendation 8

Support ISOSS in raising awareness of the importance of reporting via communications, including newsletters and presence at appropriate conferences.

Progress

The ISOSS UCL team continue to attend conferences and present findings where appropriate, supported by the IDPS programme and NHS England.

Recommendations 9 and 11

Provide links to peer-support organisations for screening teams for women who screen positive.

Confirm in the programme handbook the importance of understanding confidentiality rules for pregnant women living with HIV. Healthcare providers should be aware of the woman’s right to confidentiality but must not let misinterpretation of confidentiality law negatively impact on communication with other healthcare professionals and services.

Progress

These recommendations have been acted on by:

• providing links on the ISOSS UCL website
• inclusion in the IDPS programme handbook update, which is in progress

Recommendations 10 and 12

Strengthen the laboratory handbook around the need for a process to be in place for laboratories to request repeat samples for blood in the wrong tube and samples that cannot be processed, and the follow-up of result of outstanding samples.

Strengthen wording in the programme handbook that when a woman is admitted to a maternity service and has no evidence of a screening result in this pregnancy, this should prompt the offer of screening and notification to the screening team.

Progress

These recommendations have been acted on by:

• updating the IDPS programme laboratory handbook
• reviewing and including the urgent screening process in the updated IDPS laboratory handbook

Recommendation 13

ISOSS team to promote the clinical support networks and contact databases available for clinicians to utilise via the newsletter.

Progress

Networks shared via ISOSS newsletter

Summary and next steps

The numbers of HIV vertical transmissions in England remain very low, reflecting robust antenatal screening and effective clinical management. Findings from transmissions discussed at the CERPs show that late booking, undisclosed breastfeeding and seroconversions are key issues, as well as social inequalities. A number of vertical transmissions involved women presenting unbooked in labour. The IDPS laboratory handbook covers urgent screening for women in labour.

The social circumstances now captured by ISOSS in the maternity surveillance allow for greater insights into the role of inequalities in the population as a whole as well as contextualising the CERP transmissions in greater detail.

The majority of women now already know their HIV status before pregnancy, although some women still receive their diagnosis for the first time through antenatal screening, with earlier diagnosis and initiation of ART seen over time. Although both transfer of care and circumstances where women arrived in the UK during pregnancy were associated with detectable viral load at delivery, in nearly all pregnancies women were on ART and over 90% delivered with an undetectable viral load.

ISOSS continues to monitor key areas of interest. These include increasing numbers of pregnancies to women with vertically acquired HIV, supported breastfeeding, and trends in obstetric complications, such as gestational diabetes and pre-eclampsia.

The comprehensive national surveillance carried out by ISOSS provides valuable insights into the population of pregnant women living with HIV in England, building a fully rounded clinical picture to support the screening programme and the wider objectives of NHS England. Identifying the changing trends and emerging issues means ISOSS is able to ensure visibility of the unique needs of women living with HIV and their children.

By working closely with valued maternity and paediatric respondents across the country, ISOSS is able to provide high quality and timely data to inform guidelines and national programmes. Additional impact is also gained from ISOSS’s surveillance of the other screened-for infections in pregnancy; 2022 sees the publication of our first syphilis maternity report and over the next 12 months initial findings from the maternity hepatitis B surveillance will be made available.

Background

Data-reporting processes

ISOSS HIV surveillance, previously known as the NSHPC, has been running for over 30 years and holds data on over 30,000 pregnancies to date. Maternity surveillance covers all pregnancies in women living with HIV who are diagnosed by delivery. Paediatric surveillance includes all infants born in England to diagnosed women living with HIV, along with any children diagnosed with HIV (less than 16 years of age) who are born in England or abroad seen for paediatric care in the England.

Data validation

The ISOSS team conduct extensive matching of infant and maternal reports across pregnancies and paediatric reports. Reports include complex clinical data and there are a number of data quality checks in place. Validations are in place for incoming reports, and data is checked at each stage and queried directly with respondents where inconsistencies are identified or data is missing.

Reporting timeline

Figure 8: reporting timeline for ISOSS data collection for women during pregnancy and infants after birth

Figure 8 shows the timeline of data collection by ISOSS during pregnancy and after the baby is born, for HIV and syphilis screen positive pregnancies. There are 6 data collection points.

1. Green Card reporting (from approximately 12 weeks gestation): all HIV, syphilis and hepatitis B screen positive pregnancies booked for antenatal care in the last quarter are reported to ISOSS. The green card can be edited throughout the quarter, but the submission happens at the end of a quarter.
2. Pregnancy notification form (from approximately 12 weeks gestation): initial details of pregnant woman, care in pregnancy and pregnancy status. This form is generated for each woman following the submission of the green card.
3. Pregnancy outcome form (birth): woman’s delivery details and initial care of the infant recorded and reported. This form is available around the expected date of delivery but can be released earlier on request in cases of premature birth.
4. Paediatric notification form (1 to 6 months after birth): initial details and test results of infants seen for HIV (3 to 6 months) and syphilis (1 to 2 months) paediatric follow-up. Generated using maternity reports where possible. (Diagnosed children reported to ISOSS at any age when seen for paediatric care.)
5. Paediatric syphilis follow-up form (3 to 6 months after birth): generated for all infants born to women treated for syphilis in pregnancy and/or infants requiring treatment for syphilis until discharged.
6. Paediatric HIV follow-up form: generated for all HIV-exposed infants requesting 22 to 24 month confirmatory antibody test to establish infection status.

Acknowledgements

We would like to thank all those involved in collecting the data and producing the report, and most of all those from the NHS who deliver the infectious diseases in pregnancy screening programme. We would like to acknowledge the important contributions made by the members of our Clinical Expert Review Panel and NHS providers in relation to reviewing reports of vertical transmission of HIV.

HIV Clinical Expert Review Panel members

The HIV CERP members who contributed to the vertical transmission reviews included in the report (2021 to 2022) are:

• Dr Alasdair Bamford, Consultant and Speciality Lead in Paediatric Infectious Diseases, GOSH

• Lisa Bullows, Specialist Screening Midwife, Birmingham Women’s Hospital

• Dr Laura Byrne, Consultant in HIV Medicine, St George’s University Hospitals NHS Foundation Trust, Chair of the BHIVA HIV and Pregnancy Guidelines Writing Group

• Sarah Dermont, IDPS Clinical Projects Coordinator, NHS IDPS programme

• Maria Dowie, Clinical Nurse Specialist, Leeds Teaching Hospitals NHS Trust

• Temi Fayoyin, ANNB Screening and Immunisation Coordinator, Croydon University Hospital

• Kate Francis, ISOSS Coordinator, UCL GOS Institute of Child Health

• Dr Yvonne Gilleece, Honorary Clinical Professor and Consultant in HIV Medicine & Sexual Health, Brighton and Sussex Medical School and University Hospitals Sussex NHS Trust, Lead for HIV and Women, Lead for HIV and Hepatitis, Honorary Secretary of BHIVA

• Dr Abha Govind, Consultant Obstetrician and Gynaecologist, North Middlesex University Hospital NHS Trust

• Julia Langley, ANNB Screening Specialise Midwife, Portsmouth Hospitals NHS Trust

• Dr Hermione Lyall, Consultant in Paediatric Infectious Disease, Imperial College Healthcare NHS Trust

• Dr Kim McLeod, Consultant Obstetrician, Manchester University Hospitals NHS Foundation Trust

• Dr Paddy McMaster, Consultant in Paediatric Infectious Diseases, North Manchester General Hospital Women and Children’s, Manchester University Hospitals NHS Foundation Trust

• Jenny Neal, IDPS Programme Manager, NHS IDPS programme

• Nadia Permalloo: Head of Quality Assurance Development (Clinical), Screening Quality Assurance Service, NHSE

• Helen Peters, ISOSS Manager, UCL GOS Institute of Child Health

• Dr Luciana Rubinstein, Consultant in GUM, London North West University Health Trust (Northwick Park, Ealing, Hillingdon)

• Laura Smeaton, IDPS Programme Projects Manager, NHS IDPS programme

• Professor Claire Thorne (Chair), Professor of Infectious Disease Epidemiology, Population, Policy and Practice Department, UCL, Great Ormond Street (GOS) Institute of Child Health

• Dr Chris Wood, Consultant HIV physician; Clinic Lead for HIV Services, North Middlesex University Hospital NHS Trust

The live register of current and past CERP members is available on the ISOSS UCL website.