Official Statistics

Sexually transmitted infections and screening for chlamydia in England: 2023 report

Updated 17 July 2024

The annual official statistics data release (data to end of December 2023). For questions about this report, please contact GUMCAD@ukhsa.gov.uk

Main points

This report provides a descriptive analysis of data on sexually transmitted infection (STI) diagnoses and screening for chlamydia in England from January to December 2023. It focuses primarily on the changes between 2022 and 2023 and also contains some trend data from 2014 to 2023. Data on STI tests and diagnoses between 2014 and 2023 are available in the accompanying data tables and slide set as well as the Sexual and Reproductive Health Profiles, which also includes data at regional and upper and lower tier local authority levels.

Among people in England:

• in 2023 there were 401,800 diagnoses of new STIs, an increase of 4.7% since 2022 (383,789)
• chlamydia diagnoses (all ages) remained stable with 194,970 diagnoses in 2023 compared to 194,244 diagnoses in 2022
• gonorrhoea diagnoses increased 7.5% from 79,268 diagnoses in 2022 to 85,223 diagnoses in 2023
• infectious syphilis diagnoses increased 9.4% from 8,693 diagnoses in 2022 to 9,513 diagnoses in 2023
• there was a larger proportional increase in syphilis diagnoses among heterosexual men and women (21.8%; from 1,608 in 2022 to 1,958 in 2023) than among gay, bisexual and other men who have sex with men (GBMSM) (7.3%; from 6,081 in 2022 to 6,527 in 2023)
• first episode genital warts diagnoses (all ages) remained stable with 26,133 diagnoses in 2023 compared to 26,068 diagnoses in 2022; amongst the largely vaccinated age group of 15 to 17 year olds diagnoses remained low (104 in 2022, then 107 in 2023)
• the impact of STIs remains greatest in young people aged 15 to 24 years; GBMSM; and some minority ethnic groups

Among women aged 15 to 24 years screened through the National Chlamydia Screening Programme (NCSP):

• 672,576 chlamydia tests were carried out in 2023, a 2.1% decrease compared to 2022 (687,197)
• there were 64,670 chlamydia diagnoses in 2023, a decrease of 4.2% compared to 2022 (67,484) – test positivity remained stable (9.8% in 2022 compared to 9.6% in 2023)

Overall trends

While this report primarily focuses on the changes between 2022 and 2023, some earlier trends are included to provide a comparison to historical sexual health service (SHS) provision and STI diagnoses prior to the COVID-19 pandemic and associated disruption to service provision. The numbers of consultations, sexual health screens and STI diagnoses in 2020 and 2021 were lower than preceding years, which should be considered when comparing recent data to data from 2019 or earlier.

Overall, there was an increase in the number of consultations (including face to face consultations at physical clinics and those via telephone or internet) delivered by SHSs in England in 2023 compared to 2022 (5.0%, from 4,392,466 to 4,610,410). Compared to 2022, the number of face to face consultations increased (7.9%, from 2,097,704 to 2,263,515) as did the number of online consultations (7.5%, from 1,816,152 to 1,951,560), while the number of telephone consultations decreased (17.4%, from 478,610 to 395,335).

Of all consultations (4,610,410) in 2023, 49.1% (2,263,515) were delivered face to face, 42.3% (1,951,560) via the internet and 8.6% (395,335) via telephone. Of all consultations, 52.0% (2,399,063) were by heterosexual women, 19.5% (900,550) were by heterosexual men, 15.5% (712,749) were by GBMSM and 0.8% (37,076) were by women who have sex with women. Data on consultations is provided in Table 3 in the accompanying data tables.

The number of sexual health screens (all diagnostic tests for one or more of chlamydia, gonorrhoea, syphilis and HIV) in 2023 increased by 8.3% (2,177,325 to 2,358,987) compared to 2022 and was 4.6% higher than 2019 (2,255,992) (Figure 1). The largest proportion of screens (46.6%; 1,099,489) were in heterosexual women and 0.9% (20,307) were in women who have sex with women. Further, 22.5% (531,121) were in heterosexual men and 17.2% (406,366) were in GBMSM. Compared to 2022, the number of new STIs also increased by 4.7% (383,789 to 401,800). The most commonly diagnosed STIs in 2023 were chlamydia (194,970, 48.5% of all new STI diagnoses), gonorrhoea (85,223, 21.2%), first episode genital herpes (27,167, 6.8%), and first episode genital warts (26,133, 6.5%).

Figure 1. Number of new STI diagnoses and sexual health screens [Note 1] among England residents accessing SHSs, 2014 to 2023

Source: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems (Table 1 and Table 4 of the accompanying data tables).

[Note 1] Sexual health screen – tests for one or more of chlamydia, gonorrhoea, syphilis and HIV.
[Note 2] Figures reported in 2020 and 2021 are notably lower than previous years due to the disruption to SHSs during the national response to the COVID-19 pandemic.

In 2023 there were increases in the numbers of gonorrhoea (7.5%, from 79,268 to 85,223), and infectious syphilis (primary, secondary and early latent stages) diagnoses (9.4%, from 8,693 to 9,513) compared to 2022 (Figure 2). In line with the increasing trend over the past decade, diagnoses of both gonorrhoea and syphilis exceeded the high levels reported in 2019 (before the COVID-19 pandemic), which were 71,133 (16.1% increase) and 8,040 (8.1% increase) respectively. The number of gonorrhoea diagnoses in 2023 was the largest annual number reported since records began in 1918, while the number of syphilis diagnoses was the largest annual number reported since 1948 (comparisons of STI trends over several decades should be made with caution given increases in the population size and in testing for STIs using more sensitive diagnostic tests over time). There was a larger proportional rise in syphilis diagnoses among heterosexual men and women (21.8%; from 1,608 in 2022 to 1,958 in 2023) than in GBMSM (7.3%; from 6,081 in 2022 to 6,527 in 2023) (Figure 3).

Diagnoses of chlamydia (in people of all age groups) have remained relatively stable (0.4%, from 194,244 to 194,970) (Figure 2). The trends in chlamydia in young people are presented in the section of this report on the NCSP. Diagnoses of first episode genital herpes increased 8.8% (24,960 to 27,167) between 2022 and 2023 but remained 21.2% lower than 2019 (34,464). Diagnoses of first episode genital warts remained stable overall (0.2% increase, from 26,086 to 26,133) between 2022 and 2023.

Trends in diagnoses of STIs since 2014 are presented in Appendix Figure A2 and Table 1 of the accompanying data tables. Data on HIV testing and diagnoses is published separately on GOV.UK.

Figure 2a and 2b. Number of new diagnoses of selected STIs among England residents accessing SHSs, 2014 to 2023

Figure 2a

Figure 2b

Source: Data from routine SHSs’ returns to GUMCAD STI and CTAD Chlamydia Surveillance Systems (Table 1 of the accompanying data tables).

[Note 3] First episode.
[Note 4] Figures reported in 2020 and 2021 are notably lower than previous years due to the disruption to SHSs during the national response to the COVID-19 pandemic.
[Note 5] Includes diagnoses of primary, secondary and early latent syphilis.

Figure 3 Number of new diagnoses of infectious syphilis [Note 6] among England residents accessing SHSs, 2014 to 2023

Source: Data from routine SHSs’ returns to GUMCAD Surveillance System (Table 2 of the accompanying data tables).

[Note 6] Includes diagnoses of primary, secondary and early latent syphilis.
[Note 7] Figures reported in 2020 and 2021 are notably lower than previous years due to the disruption to SHSs during the national response to the COVID-19 pandemic.

Populations with greater sexual health needs

Ethnic minority groups

There were 86,411 (21.5% of 401,800) diagnoses of new STIs among people of Asian, black or mixed ethnicity in 2023 (21,619, 40,275 and 24,517, respectively). However, people of black ethnicity had the highest rates of all aggregate ethnic groups (Asian, black, mixed, other, or white), although this varied among the black ethnic groups with the highest rates of many STIs in people of black Caribbean ethnicity and relatively lower rates in people of black African ethnicity (Figure 4). Among aggregate ethnic groups, people of Asian ethnicity had the lowest numbers and rates of STI diagnoses, but they experienced the largest proportional rise in diagnoses between 2022 and 2023 (a 17.7% increase from 18,375 in 2022 to 21,619 in 2023 in new STIs) (see Table 2 of the accompanying data tables), but it is important to note that, like other aggregate ethnic groups, there is considerable heterogeneity in STIs trends within the different Asian ethnic groups.

The intersectionality of gender, ethnicity, age and deprivation varies between ethnic groups, and this is also reflected in their relative rates of STIs. Previous research has found, when compared to all other ethnic groups, there were no unique clinical or behavioural factors explaining the disproportionately high rates of STI diagnoses amongst people of black Caribbean ethnicity. This ethnic disparity in STIs is therefore likely influenced by underlying socio-economic factors and the role they play in the structural determinants of health of the community. In addition, rates of STI diagnoses in different ethnic groups are influenced by the age-structure of each group, such that those with a higher proportion of younger people would be expected to have higher STI diagnosis rates. STI diagnosis rates by residential area-level deprivation are available in the slide sets which accompany this report.

Figure 4a and 4b. Rates of selected STI diagnoses among England residents accessing SHSs by ethnicity [Note 8] and STI, 2023

Figure 4a

Figure 4b

Source: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems (Table 2 of the accompanying data tables).

[Note 8] The ethnic categories above are as specified by the Office for National Statistics (ONS).
[Note 9] Includes diagnoses of primary, secondary and early latent syphilis.
[Note 10] First Episode.

The ethnic categories above are as specified by the ONS. Data is presented by disaggregated ethnic groups among people of black ethnicity to highlight the variability in rates among the ethnic group experiencing the highest rates of the most commonly diagnosed STIs, but it is important to note that there is heterogeneity among all other ethnic groups as well. People of Asian, mixed, other and white ethnicity are presented as aggregated ethnic groups for comparison in this figure, but rates by all 16 disaggregate ethnic groups are available in Table 2 of the accompanying data tables.

Gay, bisexual and other men who have sex with men

There were increases in bacterial STI diagnoses amongst GBMSM between 2022 and 2023: gonorrhoea increased 9.4% (37,095 to 40,586), chlamydia increased by 8.2% (18,223 to 19,716) and infectious syphilis increased 7.3% (6,081 to 6,527). Genital herpes also increased over the same period (11.2%; from 1,716 in 2022 to 1,908 to 2023), while genital warts increased by 5.3% from 1,770 in 2022 to 1,864 in 2023 (Figure 5).

Figure 5a and 5b. Number of diagnoses of selected STIs among GBMSM accessing SHSs, 2014 to 2023

Figure 5a

Figure 5b

Source: Data from routine returns to the GUMCAD STI Surveillance System (Table 2 of the accompanying data tables).

[Note 13] Includes diagnoses of primary, secondary and early latent syphilis.
[Note 14] First episode.
[Note 11] Figures reported in 2020 and 2021 are notably lower than previous years due to the disruption to SHSs during the national response to the COVID-19 pandemic.
[Note 12] Due to incomplete reporting of some sexual orientation data in 2021, STI diagnosis numbers for GBMSM from 2021 presented in Figure 5 have been adjusted. Full details are provided in the ‘Technical note’ in the Appendix.

There have also been increases in less frequently reported STIs such as lymphogranuloma venereum (LGV) which increased 15.9% (from 1,173 in 2022 to 1,360 in 2023). In 2023, there was a 48.5% increase in cases of sexually transmitted shigellosis in England, from 1,393 in 2022 to 2,069 in 2023. In addition, there has been an increase in the number and proportion of Shigella spp. isolates that are extensively-drug resistant (XDR), and recent outbreaks of XDR shigellosis among GBMSM highlight the concerns of limited effective treatment options. Following the emergence of the international outbreak of mpox in May 2022, which involved mainly, but not exclusively, GBMSM, there were 3,553 diagnoses of mpox in 2022, but only 137 in 2023.

The national HPV vaccination programme for GBMSM aged up to and including 45 years attending specialist SHSs and HIV clinics started across England in April 2018 following a 2 year pilot. From the pilot start in 2016 to the end of 2023, the reported data shows 33.4% of eligible attendees have received at least one dose of the HPV vaccine, and among those aged 25 and older with a first dose recorded, 54.4% have received at least 2 doses. In 2023, 17,154 eligible GBMSM were vaccinated (one dose) (compared to 17,545 in 2022). Very few GBMSM (0.8% in 2023) have not accepted this vaccine when offered it. HPV vaccination may be under-reported – please refer to the Quality and methodology information (QMI) report. Further information on the vaccination schedule can be found in the Green Book.

Young people aged 15 to 24 years

Young people experience the highest diagnosis rates of the most common STIs, and this reflects the higher rates of partner change among this age group. Young women may be more likely to diagnosed with an STI due to disassortative sexual mixing by age and gender (some young women may have older male partners). Compared to 2022, the number of new STI diagnoses in 2023 among young people aged 15 to 24 years decreased by 2.3% (170,872 to 166,899), largely due to a decrease in the number of chlamydia diagnoses (4.3%; from 108,752 in 2022 to 104,107). This change in chlamydia diagnoses is discussed further in the next section of this report. The number of gonorrhoea diagnoses amongst young people (30,007 in 2022, compared to 29,880 in 2023) has remained relatively constant (Figure 6).

Figure 6. Number of gonorrhoea diagnoses by age group, 2014 to 2023

Source: Data from routine returns to the GUMCAD STI Surveillance System (Table 2 of the accompanying data tables).

[Note 15] Figures reported in 2020 and 2021 are notably lower than previous years due to the disruption to SHSs during the national response to the COVID-19 pandemic.

The quadrivalent HPV vaccine that protects against HPV 16 and 18 (the main causes of cervical cancer) and HPV 6 and 11 (the main causes of genital warts) has been offered as part of the national vaccination programme to girls aged 12 to 13 years from September 2012 and extended to boys of the same age group from September 2019. Therefore, from 2018 all young women aged 15 to 17 years would have been offered the quadrivalent vaccine when aged 12 to 13 years.

In 2023, the rate of first episode genital warts diagnoses among young women aged 15 to 17 years was 49.7% lower than the rate in this age group in 2019, (7.6 versus 15.1 per 100,000 population in 2023 versus 2019 respectively). A decline of 68.4% (2.9 versus 9.3 per 100,000 population) was seen in heterosexual young men of the same age over the same period. Amongst 15 to 17 year olds diagnoses remained low and stable (104 in 2022 compared to 107 in 2023). Declines were also seen in both men and women aged 18 to 20 years and 21 to 24 years. These are all age groups with direct or indirect protection from the quadrivalent HPV vaccine. A substantial decline of 81.6% (16.9 versus 92.2 per 100,000 population in 2023 versus 2019 respectively) was seen in GBMSM aged 15 to 17 years, which is likely due to protection from the adolescent vaccination programme, as well as the vaccination of young GBMSM in SHSs.

Data on recent sex partners

The following section compares the distribution of sex partners in the 3 months prior to diagnosis with either gonorrhoea or syphilis in women, heterosexual men, and GBMSM.

Data on the number of recent partners reported by people attending face to face SHSs is available for 2023. Note that not all services reported this information. More information can be found in the QMI and development plan report.

Among all women, where sex partnerships were reported, gonorrhoea and syphilis were most frequently diagnosed among those with one recent sex partner (55.9%; 3,063 of 5,475 and 66.1%; 226 of 342, respectively).

Among heterosexual men, where sex partnerships were reported, gonorrhoea and syphilis were also most frequently diagnosed among those reporting one recent sex partner (44.1%; 2,791 of 6,330 and 56.7%; 279 of 492, respectively).

Lastly, among GBMSM, where sex partnerships were reported, gonorrhoea and syphilis were most frequently diagnosed among those reporting 2 or more sex partners (81.7%, 8,485 of 10,489 and 72.4%; 1,663 of 2,297, respectively).

These proportions, in each of the above 3 groups, reflect the distributions of recent sex partners among people (of each group) attending SHSs.

National Chlamydia Screening Programme

National trends

In June 2021, the primary aim of the NCSP changed to focus on reducing the health harm caused by untreated chlamydia infection. The programme has the secondary aims of reducing re-infections and onward transmission of chlamydia and raising awareness of good sexual health. With the change in policy, opportunistic screening (the proactive offer of a chlamydia test to young people without symptoms) should now focus on young women and other young people with a womb or ovaries, combined with reducing time to treatment, strengthening partner notification and re-testing. Services provided by SHSs, which include chlamydia testing as part of routine sexual health screens for people of any gender and at any age, remain unchanged.

This report relates to 2023, the second full calendar year during which the proactive, opportunistic screening was recommended for young women and other people with a womb or ovaries aged 15 to 24 years only. As chlamydia is a largely asymptomatic infection, increases in the number of infections detected and treated in young women is an indication of improved chlamydia control. The chlamydia detection rate is a Public Health Outcomes Framework (PHOF) indicator and UKHSA recommends that local authorities should be working towards the detection rate of at least 3,250 diagnoses per 100,000 women aged 15 to 24 years.

In 2023, 672,576 chlamydia tests were carried out in England among young women aged 15 to 24 years, which was 2.1% lower than in 2022 (687,197) (Table 1). This is 28.8% lower than the number of tests in 2019 (944,796).

There was a 4.2% decrease in the number of diagnoses made in 2023 (64,670) compared to 2022 (67,484). This is 25.4% lower than the number of diagnoses recorded in 2019 (86,692).  Test positivity in young women remained largely stable with a marginal decrease to 9.6% in 2023 compared to 9.8% in 2022 (Table 1). As a result, the detection rate decreased by 4.2% in 2023 (1,962 per 100,000 population) compared to 2022 (2,047 per 100,000 population) (Figure 7).

Figure 7a and 7b. Chlamydia testing coverage, test positivity and detection rates among women aged 15 to 24 years, 2019 to 2023, England

Figure 7a

Figure 7b

Source: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems (NCSP of the accompanying data tables).

[Note 16] Figures reported in 2020 and 2021 are notably lower than previous years due to the disruption to SHSs during the national response to the COVID-19 pandemic.
[Note 17] Public Health Outcomes Framework.

In 2023, there were 275,739 chlamydia tests carried out in England among young men aged 15 to 24 years, which was similar to the number recorded in 2022 (275,712). Further data on chlamydia tests and diagnoses in young men is provided in Appendix Table A2), and data for young women and men is included in the NCSP data tables.

Table 1. Chlamydia tests, diagnoses, testing coverage, test positivity and detection rate among women aged 15 to 24 years, 2022 and 2023, England

Indicator	2022	2023
Total tests	687,197	672,576
Total diagnoses	67,484	64,670
Coverage	20.80%	20.40%
Test positivity	9.80%	9.60%
Detection rate	2,047	1,962

Note for Table 1:
Coverage is the number of tests divided by population multiplied by 100.

Characteristics of young women screened for chlamydia

Chlamydia test coverage (the number of tests divided by population multiplied by 100) was highest among those of Black Caribbean ethnicity (41.6%; 15,845 out of 38,130), followed by those of Mixed ethnicity (22.2%; 35,296 out of 159,275), compared to those of white ethnicity (15.5%; 378,324 out of 2,442,225).

The detection rate was highest among those of black Caribbean ethnicity (5,258 per 100,000 population), followed by those of black ‘Other’ ethnicity (2,659 per 100,000 population), compared to those of white ethnicity (1,537 per 100,000 population).

Chlamydia testing and diagnoses also differ by level of socioeconomic deprivation. Deprivation is measured using the Index of Multiple Deprivation (IMD). The first quintile (Q1) represents the most deprived 20% of lower super output areas (LSOAs) and the fifth quintile (Q5) the least deprived 20% of LSOAs. Chlamydia test coverage was similar across all deprivation quintiles (ranging from 19.6% to 23.1%) and showed little change between 2022 and 2023 (data not shown).

As was the case in 2022, chlamydia detection rates were highest among young women living in the most deprived quintile in England (2,398 per 100,000 population) in 2023 (Figure 8). The detection rate decreased across all quintiles between 2022 and 2023 (data not shown).

Figure 8. Chlamydia detection rates among women aged 15 to 24 years by IMD quintile [Note 18], 2023, England

Source: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems (NCSP of the accompanying data tables).

[Note 18] NCSP data presented by IMD quintile is based on the location of residence of the person tested.

Testing service type

The number of tests conducted in a physical (face to face) setting among young women aged 15 to 24 was 5.6% higher in 2023 (385,183) compared to 2022 (364,587). There was a 10.9% decrease in the testing conducted using self-sampling kits via the internet between 2022 (322,610) and 2023 (287,393) (Figure 9, Table 2) (see the ‘Data sources’ section of the accompanying QMI report for further information on the different types of testing services).

Figure 9a and 9b. Chlamydia tests and diagnoses from internet and face to face testing among women aged 15 to 24 years, 2019 to 2023, England

Figure 9a

Figure 9b

Source: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems (NCSP of the accompanying data tables).

[Note 19] Figures reported in 2020 and 2021 are notably lower than previous years due to the disruption to SHSs during the national response to the COVID-19 pandemic.

Table 2a. Chlamydia tests among women aged 15 to 24 years by test setting, 2022 and 2023, England

Test setting	Number of tests in 2022	Percentage of total in 2022	Number of tests in 2023	Percentage of total in 2023	Percentage change 2022 to 2023
SHSs – specialist	140,290	20.4	160,447	23.9	14.4
SHSs – non-specialist	12,658	1.8	15,472	2.3	22.2
Internet	322,610	46.9	287,393	42.7	-10.9
GP	119,078	17.3	117,098	17.4	-1.7
Pharmacy	3,468	0.5	2,264	0.3	-34.7
Termination of pregnancy	5,766	0.8	5,237	0.8	-9.2
Unknown	7,045	1	7,059	1	0.2
Other	76,282	11.1	77,606	11.5	1.7
Total	687,197	100	672,576	100	-2.1

Table 2b. Chlamydia diagnoses among women aged 15 to 24 years by test setting, 2022 and 2023, England

Test setting	Number of diagnoses in 2022	Percentage of total in 2022	Number of diagnoses in 2023	Percentage of total in 2023	Percentage change 2022 to 2023
SHSs- specialist	19,299	28.6	20,941	32.4	8.5
SHSs- non-specialist	1,426	2.1	1,905	2.9	33.6
Internet	32,148	47.6	27,372	42.3	-14.9
GP	6,417	9.5	6,485	10	1.1
Pharmacy	416	0.6	259	0.4	-37.7
Termination of pregnancy	503	0.7	507	0.8	0.8
Unknown	518	0.8	488	0.8	-5.8
Other	6,757	10	6,713	10.4	-0.7
Total	67,484	100	64,670	100	-4.2

Table 2c. Chlamydia test positivity among women aged 15 to 24 years by test setting, 2022 and 2023, England

Test setting	Test positivity 2022 (%)	Test positivity 2023 (%)
SHSs – specialist	13.8	13.1
SHSs – non-specialist	11.3	12.3
Internet	10	9.5
GP	5.4	5.5
Pharmacy	12	11.4
Termination of pregnancy	8.7	9.7
Unknown	7.4	6.9
Other	8.9	8.7
Total	9.8	9.6

Note for Table 2:
‘Other’ test setting includes chlamydia screening offices, antenatal and obstetric services, military, education, occupational health, prison, youth services, outreach, accident and emergency, minor injuries, NHS walk-in centres and hospitals.

Between 2022 and 2023, the number of chlamydia tests in women aged 15 to 24 years in specialist SHSs increased by 14.4% (from 140,290 to 160,447). There were also increases in numbers of tests in non-specialist SHSs (22.2%, from 12,658 to 15,472). Most other testing service types saw declines in numbers of tests.

Local and regional differences in chlamydia detection rates are due to a combination of differences in overall chlamydia testing coverage, the settings used to offer chlamydia testing and the underlying prevalence of infection. Data on chlamydia detection rates at region and upper and lower tier local authority levels is available in the Sexual and Reproductive Health Profiles.

Concluding comments

There was an increase in all consultations (face to face, telephone or online) overall at SHSs in England between 2022 and 2023, with more face to face and online attendances accounting for the rise. However, when compared to 2019 (the year prior to the COVID-19 pandemic), there were still fewer attendances overall, and substantially fewer face to face attendances in 2023; the scale up of online consultations has contributed to an overall increase in all consultations over this period, but there is evidence of inequality of use of online services and some people may find it difficult to be tested for STIs using these services. Among young women aged 15 to 24 years, there was a reduction in chlamydia tests and diagnoses between 2022 and 2023; this was largely due to a drop in online testing.

The number of sexual health screens provided by SHSs (for people of all ages) increased by 8.3% between 2022 and 2023, and this contributed to rises in gonorrhoea (7.5%) and syphilis (9.4%). However, the continued increases in these STIs may also reflect ongoing high levels of transmission in the community. There were more diagnoses of both syphilis and gonorrhoea among GBMSM in 2023, but there were larger proportional rises in diagnoses among heterosexuals between 2022 and 2023. In 2023, STIs continue to disproportionately impact GBMSM; people of black Caribbean ethnicity, and young people aged 15 to 24 years.

Following the large increase in gonorrhoea diagnoses in young people between 2021 and 2022, the number of diagnoses in aged 15 to 24 years plateaued, but remained high, in 2023. Through the NCSP, the offer of opportunistic chlamydia screening to sexually active young women aged 15 to 24 years is important to prevent the harms of untreated chlamydia infection, including pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility.

The inclusion of behavioural data on number of recent sex partners with routine GUMCAD STI surveillance submissions from SHSs, presented in this report and the accompanying data tables for the first time this year, allows for greater contextualising of STI diagnoses by understanding risk behaviours. This data will also allow better understanding of the need for and targeting of interventions to those at higher risk of STIs including of new preventative measures described in the following section.

Public health measures to address the rise in STIs

There are novel biomedical preventative interventions on the horizon for bacterial STIs. In November 2023, the Joint Committee on Vaccination and Immunisation (JCVI) published advice recommending a targeted opportunistic vaccination programme for gonorrhoea at SHSs using 4CMenB vaccine; their recommendation was to primarily target GBMSM who are at increased risk of infection, but to also vaccinate others, including transgender women, gender diverse people assigned male at birth, and heterosexuals, at similar risk of gonorrhoea. Additionally, UKHSA is working with the British Association for Sexual Health and HIV (BASHH) on the UK’s first national guideline for the use of doxycycline post-exposure prophylaxis for the prevention of bacterial STIs.

To address the increase in syphilis diagnoses in England, UKHSA published a Syphilis Action Plan which focuses on key interventions to control and prevent this infection, such as more frequent testing for GBMSM at higher risk of syphilis, partner notification, and raising awareness about this infection. UKHSA actively monitors and rapidly responds to cases of gonorrhoea with resistance to ceftriaxone, the current first-line therapy. An equivalent sentinel surveillance system has been set up for Mycoplasma genitalium. UKHSA also contributed to the NICE reducing STIs guideline, and conducts research with academic partners through the National Institute for Health and Care Research funded Health Protection Research Unit (HPRU) to better understand risk and risk reduction for STIs.

UKHSA supports local areas to interpret and utilise data to inform local action to improve public health and address health inequalities in accessing SHSs and outcomes of care, including through care pathway workshops for chlamydia, syphilis and HIV. These workshops provide local commissioners and providers with a comprehensive case management pathway to improve service delivery which also includes data to inform actions to help reduce inequalities in accessing SHSs.

Appendix

Data sources

Data on STI tests and diagnoses is submitted by SHSs to the GUMCAD STI Surveillance System. Data on chlamydia tests and diagnoses is submitted by laboratories to the CTAD Chlamydia Surveillance System. Both of these surveillance systems are managed by UKHSA and, in combination, provide a comprehensive picture of STI trends in England. These systems are detailed below.

GUMCAD

The GUMCAD STI Surveillance System was established in 2008 as an electronic surveillance system to collect disaggregated, pseudonymised and depersonalised patient-level data from SHSs on all STI tests and diagnoses. In 2019, UKHSA commenced implementation of a new version of this data set, the GUMCAD Behavioural Specification (GUMCADv3), which includes additional information such as:

• proportion of diagnoses that are asymptomatic
• outcomes of partner notification
• provision of HIV pre-exposure prophylaxis (PrEP)

CTAD

The CTAD Chlamydia Surveillance System is a  disaggregate data set that collects pseudonymised and depersonalised chlamydia data from all laboratories commissioned by local authorities or the NHS to carry out chlamydia testing. This report includes the data on chlamydia tests and diagnoses from all publicly commissioned chlamydia testing services.

Data definitions

Trends in ‘New STIs’ are discussed in this report. ‘New STIs’ include the following:

• chancroid
• chlamydia
• donovanosis
• gonorrhoea
• genital herpes (first episode)
• HIV [Caveat 1]
• Lymphogranuloma venereum (LGV)
• molluscum contagiosum [Caveat 1]
• Mycoplasma genitalium
• non-specific genital infection
• pediculosis pubis [Caveat 1]
• pelvic inflammatory disease and epididymitis [Caveat 1]
• scabies [Caveat 1]
• Shigella flexneri, sonnei, spp (unspecified) [Caveat 1]
• infectious syphilis (primary, secondary, early latent stages)
• trichomoniasis
• genital warts (first episode)

[Caveat 1] Infections that are not exclusively transmitted by sexual contact.

The ‘New STI diagnoses’ group was expanded in 2015 to include STI diagnoses that were not previously reported via GUMCAD (Shigella spp and Mycoplasma genitalium infections). Therefore, data from 2015 and earlier is not directly comparable to data from previous years.

Data quality

Every effort is made to ensure that data quality standards are maintained by conducting regular analysis and data quality assessments. In the event that data quality issues are identified, they are followed-up directly with data reporters and their associated software providers to identify and resolve any issues – which may result in the resubmission of corrected data.

Please note that CTAD and GUMCAD data included in official statistics publications is updated on an annual basis, therefore numbers may differ from previous publications – where resubmissions of corrected data have been subsequently received and included. Furthermore, please also note that, where corrected data cannot be resubmitted in time for an official statistics release, data may be imputed.

Further details on data sources and data quality can be found in the accompanying QMI report.

Technical note on imputing the STI diagnosis totals in GBMSM for 2021

The number of diagnoses of chlamydia, gonorrhoea, infectious syphilis, genital herpes and genital warts in GBMSM was imputed in 2021 to account for under reporting of diagnoses in this key population due incomplete reporting of sexual orientation from a large SHS in 2021.To impute the number of STI diagnoses in GBMSM in 2021 from this SHS, we did the following:

• using GUMCAD data from January to December 2019, we determined the proportion of each STI diagnosis in men attending that SHS that was reported in men who were gay or bisexual – 2019 data was used because this is the most recent year for which sexual orientation was reported with over 90% completion by this SHS
• assuming that the same proportions of men diagnosed with each STI at this SHS in 2021 were gay or bisexual, we then used that proportion to derive an adjusted number of STI diagnoses in GBMSM from that SHS in 2021
• this adjusted total was then used to derive the total number of STI diagnoses in GBMSM for that clinic (data not shown) and for all of England

No further adjustments were made to data from that SHS for any other year up to and including 2020. No adjustments were applied to data from any other SHSs as they had high data completion for sexual orientation.

Had we not applied this adjustment, the figures would suggest a decrease in several bacterial STI diagnoses in GBMSM in 2021 (see Figure A1). However, this would have solely been due to an artefact of the incompleteness of the data.

Figure A1a and A1b. Adjusted and unadjusted number of new diagnoses of selected STIs among GBMSM accessing SHSs, England, 2014 to 2023

Figure A1a

Figure A1b

Source: Data from routine returns to the GUMCAD STI Surveillance System (Table 2 of the accompanying data tables).

[Note 22] Includes diagnoses of primary, secondary and early latent syphilis.
[Note 23] First episode.
[Note 20] Figures reported in 2020 and 2021 are notably lower than previous years due to the disruption to SHSs during the national response to the COVID-19 pandemic.
[Note 21] The number of STI diagnoses in GBMSM in 2021 was adjusted to account for incomplete reporting of some sexual orientation data.

Additional analyses

Figure A2 shows the trends in the number of diagnoses of syphilis, gonorrhoea, genital herpes and genital warts, by women and men residing in England, 2014 to 2023.

Figure A2a. New diagnoses of syphilis by gender among England residents accessing SHSs, 2014 to 2023

Figure A2b. New diagnoses of gonorrhoea by gender among England residents accessing SHSs, 2014 to 2023

Figure A2c. New diagnoses of genital herpes [Note 26] by gender among England residents accessing SHSs, 2014 to 2023

Figure A2d. New diagnoses of genital warts [Note 26] by gender among England residents accessing SHSs, 2014 to 2023

Source: Data from routine SHSs returns to the GUMCAD STI Surveillance System (Table 1 of the accompanying data tables).

[Note 24] Includes diagnoses of primary, secondary and early latent syphilis.
[Note 25] Figures reported in 2020 and 2021 are notably lower than previous years due to the disruption to SHSs during the national response to the COVID-19 pandemic.
[Note 26] First Episode.

Table A2a. Chlamydia tests among men aged 15 to 24 years by test setting, 2022 and 2023, England

Test setting	Number of tests in 2022	Percentage of total in 2022	Number of tests in 2023	Percentage of total in 2023	Percentage change 2022 to 2023
SHSs – specialist STI related care	79,316	28.8	90,365	32.8	13.9
SHSs – non-specialist STI related care	4,378	1.6	6,393	2.3	46
Internet	147,418	53.5	132,804	48.2	-9.9
GP	15,530	5.6	17,748	6.4	14.3
Pharmacy	1,040	0.4	753	0.3	-27.6
Termination of pregnancy	53	0	14	0	-73.6
Unknown	1,724	0.6	1,473	0.5	-14.6
Other	26,253	9.5	26,189	9.5	-0.2
Total	275,712	100	275,739	100	0.01

Table A2b. Chlamydia diagnoses among men aged 15 to 24 years by test setting, 2022 and 2023, England

Test setting	Number of diagnoses in 2022	Percentage of total in 2022	Number of diagnoses in 2023	Percentage of total in 2023	Percentage change 2022 to 2023
SHSs – specialist STI related care	13,813	37.5	15,029	42	8.8
SHSs – non-specialist STI related care	738	2	1,076	3	45.8
Internet	17,272	46.9	14,672	41	-15.1
GP	1,624	4.4	1,813	5.1	11.6
Pharmacy	164	0.4	129	0.4	-21.3
Termination of pregnancy	13	0	2	0	-84.6
Unknown	181	0.5	128	0.4	-29.3
Other	2,998	8.1	2,961	8.3	-1.2
Total	36,803	100	35,810	100	-2.7

Table A2c. Chlamydia test positivity among men aged 15 to 24 years by test setting, 2022 and 2023, England

Test setting	Test positivity 2022 (percentage)	Test positivity 2023 (percentage)
SHSs – specialist STI related care	17.4	16.6
SHSs – non-specialist STI related care	16.9	16.8
Internet	11.7	11
GP	10.5	10.2
Pharmacy	15.8	17.1
Termination of pregnancy	24.5	14.3
Unknown	10.5	8.7
Other	11.4	11.3
Total	13.3	13

Source: Data from routine SHSs returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems (NCSP of the accompanying data tables).

Note for Table A2:
‘Other’ test setting includes chlamydia screening offices, antenatal and obstetric services, military, education, occupational health, prison, youth services, outreach, accident and emergency, minor injuries, NHS walk-in centres and hospitals.

Resources on the UKHSA website

For more information:

• STI data on the UKHSA STI annual data tables web page in the form of tables and a slide set
• data on chlamydia tests and diagnoses in adults aged 15 to 24 years are available on the UKHSA NCSP annual data tables web page
• interactive tables, charts, and maps showing local-area STI data is available on the Sexual and Reproductive Health Profiles
• GUMCAD and CTAD Surveillance Systems
• Gonococcal Resistance to Antimicrobials Surveillance Programme (GRASP)
• trends in mpox
• trends in HIV diagnoses in the UK
• latest LGV surveillance data for the UK
• latest guidance and data on Shigella spp

Acknowledgments

Contributors to Official Statistics (in alphabetical order): Emma Ackermann, Claudia Adighije, Anja Anderson, Cuong Chau, Carol Chatt, Shivani Chokupermal, Helen Corkin, Ubah Daahir, Srilaxmi Degala, Dhruv Desai, Kate Donohoe, Vicky Dowling, Jon Dunn, Grahame Davis, Lynsey Emmett, Miranda Ferguson, Josh Forde, Kate Houseman, Gareth Hughes, Danielle Jayes, Tobi Kolawole, Geraldine Leong, Elizabeth McCrae, Clare Macdonald, Neil Mackay, Debbie Mou, Emmanuel Musah, Tani Obasaju, Shahin Parmar, Dawn Philips, Andy Raynor, James Sedgwick, Victoria Shoemig, Alireza Talebi, Eliza Thomson, Roberto Vivancos, Megan Walsh, Georgina Wilkinson, Brennan Winer, Nick Young

Authors: Stephanie J Migchelsen, Jessica Edney, Norah O’Brien, Celine El Hakim, Prarthana Narayanan, Ana Karina Harb, Lana Drisdale-Gordon, Stephen Duffell, Marta Checchi, Lucinda Slater, Hannah Charles, George Baldry, Hridhya Vijayan, Giulia Habib Meriggi, Tika Ram, Kate Soldan, Kate Folkard, Katy Sinka, Hamish Mohammed

Suggested citation

Stephanie J Migchelsen, Jessica Edney, Norah O’Brien, Celine El Hakim, Prarthana Narayanan, Ana Karina Harb, Lana Drisdale-Gordon, Stephen Duffell, Marta Checchi, Lucinda Slater, Hannah Charles, George Baldry, Hridhya, Vijayan, Giulia Habib Meriggi, Tika Ram, Kate Soldan, Kate Folkard, Katy Sinka, Hamish Mohammed and contributors. Sexually transmitted infections and screening for chlamydia in England, 2023. June 2024, UK Health Security Agency, London

Definition of official statistics

They are statistics produced by Crown bodies and other organisations listed within an Official Statistics Order, on behalf of the UK government or devolved administrations. They provide a factual basis for assessment and decisions on economic, social and environmental issues at all levels of society.

Our statistical practice is regulated by the Office for Statistics Regulation (OSR). OSR sets the standards of trustworthiness, quality and value in the Code of Practice for Statistics that all producers of official statistics should adhere to. You are welcome to contact us directly by emailing GUMCAD@ukhsa.gov.uk with any comments about how we meet these standards. Alternatively, you can contact OSR by emailing regulation@statistics.gov.uk or via the OSR website.

The UKHSA is committed to ensuring that these statistics comply with the Code of Practice for Statistics. This means users can have confidence in the people who produce UKHSA statistics because our statistics are robust, reliable and accurate. Our statistics are regularly reviewed to ensure they support the needs of society for information.  

UKHSA will next be conducting a formal review of these statistics in Summer 2024. Following this review, an implementation plan will be developed to continue to improve the trustworthiness, quality, and value of these statistics. Key continuous improvements made will be highlighted within future releases of these statistics for transparency.