Research and analysis

TB prevention in England, 2021

Updated 3 August 2023

Applies to England

About this report

Report series

This report presents people with tuberculosis (TB) disease notified to the enhanced surveillance scheme in England and aims to describe the epidemiology of TB in England up to the end of 2021. It is the sixth in a series of 7 reports that will describe different aspects of TB incidence, treatment and prevention in England as shown below:

1. TB incidence and epidemiology in England, 2021
2. TB diagnosis, microbiology and drug resistance in England, 2021
3. TB in children: incidence, epidemiology and microbiology in England, 2021
4. TB treatment in England, 2021
5. TB treatment outcomes in England, 2021
6. TB prevention in England, 2021
7. TB in children: treatment and prevention in England, 2021

Report format

Information on how this series of reports fits within the TB action plan for England 2021 to 2026, jointly published with NHS England (NHSE), along with a list of key monitoring indicators for the entire report series, can be found in the first report TB incidence and epidemiology in England, 2021.

Topics and corresponding action plan monitoring indicators

Contact tracing of people notified with active TB:

• Indicator 3: Proportion of people with pulmonary TB with a minimum of 5 close contacts identified and screened
• Indicator 4: Proportion of people who are contacts with a positive latent TB infection (LTBI) test completing LTBI treatment

Latent TB testing and treatment programme of new entrants:

• Indicator 5: Proportion of new entrant migrants who take up the offer of an LTBI test
• Indicator 6: Proportion of new entrant migrants diagnosed with LTBI who complete treatment

Pre-entry screening for active TB in long-term migrants:

• Indicator 2: Reduce the proportion of TB individuals in those born outside of the UK in whom TB occurs within 5 years of entry

Main messages

Prevention of tuberculosis (TB) disease involves identifying, testing and treating people at higher risk of latent TB infection (LTBI) as a result of contact with a known infectious individual or because they have migrated from a high incidence country.

Contact tracing requires timely identification of contacts of people with infectious TB and assessment for active or latent infection in those individuals.

The target in the national action plan is for 90% of people with infectious TB to have at least 5 contacts traced; only 20% of people with information recorded in 2021 met this target, lower than in previous years.

LTBI in contacts of people with infectious TB should be treated to prevent progression to active TB disease; 60% of contacts with LTBI were recorded as completing treatment in 2021.

The pre-entry screening programme for active pulmonary TB in migrants from high incidence countries who apply for visas valid for more than 6 months aims to reduce importation of infectious TB.

The NHSE LTBI programme for testing of migrants from high incidence countries aims to test 25% of eligible migrants; in 2021 this figure was 9.4%.

Reasons for the low percentage need to be further investigated but are likely to include slow recovery of LTBI services from the COVID-19 pandemic, lack of reporting of data and reduced uptake of services.

Completion of treatment for LTBI for individuals tested as part of the NHS migrant programme is incompletely recorded, but was 25.6% in 2021, the highest figure for 5 years.

The combination of pre-entry screening for active TB and post entry screening for LTBI aims to reduce the proportion of TB within the non-UK born population, notified within 5 years of UK entry by 5% per year compared to the 2017-19 baseline of 29.1%; in 2021 the proportion rose to 32.3%.

BCG vaccination of infants and young children most at risk of exposure to TB infection aims to prevent TB disease in this group and is reported in TB in children: treatment and prevention in England, 2021.

Contact tracing

Contact tracing remains a cornerstone of TB management and prevention by interrupting chains of transmission and reducing the overall burden of disease.

Contact tracing has 3 main objectives:

• identification of individuals with undiagnosed active TB
• testing to identify people with latent infection followed by chemoprophylaxis to prevent development of active disease
• vaccination of those eligible with BCG

There is evidence that treating latent infection with chemoprophylaxis is safe and prevents progression to active disease, reducing morbidity and mortality for the individual and further spread of TB into the population

Assessment and screening of close contacts should be undertaken in line with National Institute for Health and Care Excellence (NICE) guidance.

Contact tracing data is presented from England between 2018 and 2021. Prior to this, contact tracing information was only recorded for a small minority of individuals.

Contact tracing activity by geographic distribution, demographic, and disease characteristics of TB index person

Figure 1 and Table 1 of the TB prevention in England data set describes the proportion of people notified with pulmonary TB with contact tracing information recorded by UKHSA region.

Figure 1 is a bar chart that shows in 2021, 1,588 (68%) of individuals had contact tracing information recorded with the highest proportion observed in London and the North East (83.6% and 92.0%).

Figure 1. Proportion of people notified with pulmonary TB with contact tracing information recorded by UKHSA centre, England 2021

Table 1 shows contact tracing information by demographic and social risk factors and disease characteristics in 2021. For the assessed characteristics, there were few notable differences in the proportion of people notified with TB who had contact tracing information recorded or in the proportion with at least 5 contacts screened. A slightly greater proportion of people treated for multi-drug resistant TB or rifampicin resistant TB (MDR or RR TB) had contact information recorded than those without (76% versus 68%) and this group also had the highest proportion of notifications with at least 5 contacts screened (18.5%).

Table 1. Contact tracing information for people with pulmonary TB by demographic and disease characteristics, England 2021

Category	Total number	Contact information entered (%)	5 or more contacts identified and screened (%)
All people with pulmonary TB	2,333	1,588 (68.0%)	313 (13.4%)
Male	1,505	1,005 (66.8%)	189 (12.6%)
Female	827	582 (70.4%)	124 (15.0%)
Adults	2,252	1,542 (68.5%)	301 (13.4%)
Children (15 years or less)	81	46 (56.8%)	12 (14.8%)
UK born	700	459 (65.5%)	96 (13.7%)
Non-UK born	1,605	1,117 (69.6%)	215 (13.4%)
At least 1 social risk factor	386	264 (68.4%)	46 (11.9%)
No social risk factors	1,947	1,324 (68.0%)	267 (13.7%)
MDR or RR TB	54	41 (75.9%)	10 (18.5%)
Non-MDR or RR TB	2,279	1,547 (67.9%)	303 (13.3%)

Note: Percentages are derived from the total number of notified individuals with pulmonary TB.

For those with information recorded, the distribution of the number of contacts recorded per person with TB in 2021 can be seen in Figure 2.

The median number of contacts identified per person notified with pulmonary TB was 3 (IQR: 1 to 5), with only 29.2% of people notified with pulmonary TB with at least 5 contacts identified. A further 10.8% had zero contacts recorded, which could reflect a reluctance to disclose information or actual number of contacts identified. This suggests that reaching a target of 90% with at least 5 contacts identified and screened might be unachievable.

Figure 2. Histogram of number of contacts per notification of infectious TB, England 2021

In 2021, little difference in contact tracing between people with pulmonary and non-pulmonary TB was observed with 62.8% of people with non-pulmonary TB having contact information recorded (1,314 out of 2,091) but with fewer contacts recorded (median of 1 contact; IQR: 0 to 3 close contacts). Contact tracing practices vary between services, with some services routinely carrying out contact tracing on individuals with non-pulmonary disease.

Figure 3 is a flowchart that describes the attrition between some of the steps during the process of contact tracing and screening in 2021, from the identification of named close contacts to conducting screening in those contacts and then obtaining results. The greatest proportion of missing data occurred at the stage of identifying close contacts in NTBS which may be due to a lack of completion of data rather than actual practice. There was no indication that people with fewer contacts identified had more complete tracing and screening.

Figure 3 description

The diagram shows the number and proportion of individuals with contact information in England in 2021. It starts with 2,333 pulmonary cases, of which 745 (31.9%) are missing contact information.

Of the 1,588 (61.1%) cases that did have contact tracing information entered, 6, 018 contacts were identified. This is a median of 3.8 identified for every individual notified with pulmonary TB.

Of the 1,588 cases that did have contact tracing information entered, 172 (10.8%) had zero contacts entered, and therefore no contacts were identified.

Of those 1,588 cases, 953 (60.0%) had 1 to 4 contacts identified. Of these 953 cases, 224 (23.5%) had no information recorded for contacts, leaving 729 (76.5%) who did have information recorded for contacts and who were assessed with further screening. Of these 729, 44 (6.0%) had zero contacts assessed and 685 (94.0%) had 1 to 4 contacts assessed.

Of those 1,588 cases, 463 (29.2%) had 5 or more contacts identified. Of these 463 cases, 73 (15.8%) had no information recorded for contacts, leaving 390 (84.2%) who did have information recorded for contacts and who were assessed with further screening. Of these 390, 6 (1.5%) had zero contacts assessed, 71 (18.2%) had 1 to 4 contacts assessed, and 313 (80.3%) had 5 or more contacts assessed.

Figure 3. Flow chart of the number and proportion of individuals with contact information entered, England 2021

Action plan indicator 3: Proportion of individuals notified with pulmonary TB with a minimum of 5 close contacts identified and screened

Figure 4 is a bar chart that shows data for Indicator 3 of the TB action plan for 2021 to 2026 with a target of 90% of individuals notified with pulmonary TB to have at least 5 close contacts screened for latent TB. England did not reach this target in 2021. When calculated as a percentage of people with pulmonary TB and contact information recorded (1,588), 19.7% (313 people) had 5 or more contacts identified and screened for active TB and latent TB infection. This is the lowest recorded since comparable levels of non-missing data were available. When calculated as a proportion of all people with pulmonary TB (2,333) this is reduced further to 13.4%.

Figure 4. Proportion of people notified with pulmonary TB with at least 5 contacts identified and screened for active and latent TB by year, England

Note: Contact information was missing for 31.9%, 28.3%, 29.2 and 49.8% of people notified with pulmonary TB in 2021, 2020, 2019 and 2018 respectively.

Screening and treatment results in close contacts

Table 2 shows the numbers and proportion of adult and child contacts identified, screened, tested positive for LTBI, started and completed treatment. 6,018 contacts were identified from 1,588 people notified with pulmonary TB (the index individuals), 70% of whom were screened for active and latent TB, of whom 20% tested positive for latent TB and 3.6% were reported to have active TB disease.

The proportion of identified contacts who were children (aged under 14 years) was 25.6%. The proportion of identified contacts who were screened was similar between adult and child contacts, but the proportion of those screened reported to have active TB was higher in child compared to adult contacts (4.1% versus 3.5%) as was the proportion with LTBI (24.5% versus 18.5%).

Table 2 of the TB prevention in England data set shows the same data by UKHSA region. The proportion of contacts found to have active TB ranged from a low of 1.6% in the South East to a high of 4.5% in the West Midlands and the North East. The proportion of contacts who tested positive for latent TB ranged from a low of 14.8% in the South West to a high of 23.7% in the East of England.

Table 2. Number of contacts identified, screened, screening results and treatment for contacts of people notified with pulmonary TB (index individuals), England 2021

	All Adult contacts	All Child contacts	Total contacts
Number of contacts identified	4,476	1,542	6,018
Number of contacts screened for active TB and latent TB (%)	3,093 (69.1%)	1,130 (73.3%)	4,223 (70.2%)
Number of contacts with active TB (%)	107 (3.5%)	46 (4.1%)	153 (3.6%)
Number of contacts with latent TB (%)	571 (18.5%)	277 (24.5%)	848 (20.1%)
Number of contacts who started treatment for latent TB (%)	412 (72.2%)	254 (91.7%)	666 (78.5%)
Number of contacts who completed treatment for latent tuberculosis (%)	303 (53.1%)	205 (74.0%)	508 (59.9%)

Note 1. The denominator for proportion of contacts screened for active TB and latent TB infection is number of contacts identified.</br> Note 2. The denominator for the proportion of contacts positive for active TB and LTBI is the number of contacts screened.</br> Note 3. The denominator for the proportion of contacts who started and completed treatment is the number of contacts positive for LTBI.

Action plan indicator 4: Proportion of contacts with a positive LTBI test completing treatment

Action plan indicator 4 is to report annually on the proportion of close contacts of people notified with pulmonary TB who complete LTBI treatment following a positive test compared with a baseline average from 2021 and 2022.

In 2021, for adult and child contacts combined, 78.5% with a positive LTBI test started treatment for latent TB and 59.9% were recorded as having completed treatment. A greater proportion of children than adults completed treatment for LTBI (74.0% versus 53.1%).

Yorkshire and the Humber had the highest rate of treatment completion at 74.5%. This is shown in Table 2 of the TB prevention in England data set which shows the number of identified contacts that were assessed with further screening information by UKHSA centre.

Figure 5 is a bar chart that shows the number and proportion of pulmonary TB contacts completing treatment for LTBI, out of those who tested positive by place of birth and age (adult or child) of the index case. Treatment completion rates were higher for contacts of index individuals who were born outside the UK compared to those who were born in the UK; and higher for contacts of adult index individuals than contacts of child index individuals.

Figure 5. LTBI treatment completion in close contacts of adult or child and UK born or non-UK born index individuals, England 2021

From available data, in 2021, contact screening of people notified with pulmonary TB resulted in a yield of 153 people with active TB disease detected from 1,588 index individuals and 6,018 contacts, equivalent to 1 new individual with active TB for every 10.4 index individuals and every 39.3 attempted screens. The yield of individuals detected with LTBI and successfully treated was 508, equivalent to 1 person with LTBI treated and prevention of progression for every 3.1 index individuals and 11.8 attempted screens.

National latent TB infection testing and treatment programme for new entrants

The NHSE National Latent TB Infection testing, and treatment programme was introduced in 2015 as part of the Tuberculosis (TB): collaborative strategy for England (2015 to 2020).

The programme is commissioned and managed by NHSE with UKHSA providing the support for the running of the database for data collection, the analysis of these data and the submission of these data to NHSE to allow payment to CCGs for the service. The programme is monitored and evaluated by NHSE based on data submitted to and reported on by UKHSA to NHSE and LTBI programme partners.

The NHSE commissioned LTBI programme tests new entrants to the UK based on the following eligibility criteria:

• born or spent more than 6 months in a high TB incidence country (more than or equal to 150 per 100,000 or Sub-Saharan Africa)
• entered the UK within the last 5 years (including entry via other countries)
• aged between 16 to 35 years.
• no previous history of TB or LTBI
• not previously screened for LTBI in the UK

The NHSE LTBI commissioned programme aims to test 25% of eligible migrants within the programme on the current resource allocation.

In 2015 the programme started in 59 high priority Clinical Commissioning Groups (CCGs) with TB rates of more than or equal to 20 per 100,000 population and or greater than 0.5% of England’s total TB notification numbers. In 2021, the national programme was commissioned in 31 CCGs. This number reflects organisational changes and CCG mergers and includes the areas of the original 59 CCGs from 2015. Geographical areas covered by the programme remain focused in areas with high TB incidence.

In 2021, of the 31 commissioned CCGs, 29 submitted testing data to the LTBI portal and 21 reported treatment completion data (this data return is not mandatory). Throughout 2021 there were shortages of TB medication which may have impacted treatment completion.

A small number of CCGs have local arrangements for LTBI testing and treatment outside of the nationally commissioned programme, for which no data are received by UKHSA and are not reported here.

The section below presents data from 2016 to 2021. Information on the LTBI data set, testing and treatment outcomes, and CCG to ICB changes are available in the Methods and definitions section.

LTBI test data and positivity rates

Figure 6a and 6b are charts that show the number of valid tests performed for the 29 CCGs reporting data to the portal in 2021 in England by UKHSA centre.

In 2021, 13,995 new entrants were reported as tested for LTBI with a valid test result returned. This represents a 33.2% increase the number of people tested compared with 2020 (10,510) when the new entrant LTBI programme was paused for 10 months due to the COVID-19 pandemic.

Although there was an increase in testing numbers in 2021 these data indicate that the programme had not fully recovered to pre COVID-19 levels as there was 17.2% decrease in the numbers tested when compared with 2019 (16,900) Table 3 of the TB prevention in England data set.

All regions apart from the East Midlands saw an increase in programmatic LTBI testing between 2020 and 2021 reflecting post pandemic recovery. In addition, some areas show an indication of recovery to pre pandemic levels. Yorkshire and the Humber regional centre saw the largest increase in number of tests conducted which also covered pre-pandemic years. This is shown in Table 4 of the TB prevention in England data set.

Numbers of completed tests and associated positivity may vary compared to older published reports. This is due to additional retrospective data uploads and processing of these data.

Figure 6a. Number of valid LTBI tests by UKHSA centres excluding London, England, 2016 to 2021

Note: The North East is not presented here as the LTBI programme does not operate in this area.

Figure 6b. Number of valid LTBI tests by the London UKHSA centre, England, 2016 to 2021

Figures 7a and 7b and Table 3 of the TB prevention in England data set shows the number of valid tests and proportion of tests positive for latent TB infection (positivity rate) from 2016 to 2021. The number of tests and positivity rates by region are summarised in Table 4 of the TB prevention in England data set.

In 2021 of the 13,995 people tested through the programme 2,018 people tested returned a positive test, giving an overall positivity rate of 14.4%. This positivity rate has declined over the 4-year period from 21.7% in 2016.

Figure 7a. Number of valid LTBI tests, England, 2016 to 2021

Figure 7b. Overall positivity rates for LTBI tests, England, 2016 to 2021

Action plan indicator 5: Proportion of new entrant migrants who take up the offer of an LTBI test

This TB action plan indicator is focused on the proportion of new entrant migrants who take up an offer of an LTBI test. To establish a baseline for this indicator this report has used the available data to make an estimate of the number of eligible migrants and those that have been reported as tested for LTBI through the NHSE commissioned programme. The target for this indicator was stated in the action plan as a 15% increase per year from a 2019 to 2020 baseline. However, due to data limitations this is the first year that this indicator can be assessed with reasonable confidence.

Flag 4 GP Registration data was available to estimate the number of migrants eligible through the NHSE commissioned programme. It is used to identify individuals who have registered with a GP service within a specified period under the CCGs participating in the LTBI programme. These data are used to identify and invite the eligible migrants (which has been used as the denominator) for LTBI screening by the TB services under these CCGs.

Within the programme, 28 out of the 29 CCGs submitting data in 2021 received Flag 4 data to carry out programmatic screening and can be included in this analysis. In 2021, 146,078 migrants were identified as eligible through Flag 4 data and 13,712 (9.4%) were screened.

These data are summarised in Table 5 of the TB prevention in England data set. Figure 8 shows the number of migrants identified for LTBI testing via Flag 4 data in 28 CCGs.

Figure 8. Number of migrants identified and screened by quarter, England 2021

Action plan indicator 6: Proportion of new entrant migrants diagnosed with LTBI who complete treatment

The LTBI portal collects data on both the referral for treatment and the completion of treatment. There is no additional payment for recording these data within the LTBI portal. In 2021, treatment data was submitted by 21 out of 29 CCGs in 2021. Incomplete data fields and data recording limit the conclusions that can be reported here for changes over time. In addition, drug supply shortages may have affected treatment completion.

Treatment completion was calculated by dividing the number of individuals recorded having completed treatment by the number of positive tests. This data by year (2016 to 2021) and by CCG is reported in Table 6 of the TB prevention in England data set.

Figure 9a is a bar chart that shows the number of migrants reported as testing positive for LTBI and as having completed treatment within the programme between 2017 and 2021.

Figure 9b is a bar chart that shows the recorded treatment completion rate since 2016. Treatment completion in 2021 was 25.6% (516 out of 2,018), significantly higher compared with all previous years apart from a previous high in 2017 at 23.8% (472 out of 1984). The target for this indicator is a 20% increase per year compared with a 2019 to 2020 baseline, equivalent to 20.5%. In 2021 compared with this baseline there was a 24.9% increase in TB treatment completion, the largest increase observed so far.

Figure 9a. Number of eligible migrants reported as testing positive for LTBI and number of those who completed chemo-prophylactic treatment by year, England 2016 to 2021

Figure 9b. Proportion of migrants with a positive test that completed treatment by year, England 2016 to 2021

The number of migrants who started and completed treatment by UKHSA centre in 2021 is shown in Figure 10. Recorded treatment completion proportion varied considerably by region.

In 2021, the North West UKHSA regional centre had the highest proportion of overall completion with 49.2%, followed by the South West (48.7%) and Yorkshire and the Humber (44.3%). Interpretation of this should be with caution due to issues with data completeness and the pause of activity in some CCGs and slower recovery from the programme pause due to the COVID-19 pandemic. Table 7 of the TB prevention in England data set shows this data by UKHSA centre from 2016 to 2021.

Figure 10. Number of migrants that tested positive for LTBI and completed treatment by UKHSA centre, England 2021

UK pre-entry TB screening programme

Introduction to the programme

In 2021, 76.4% of all the people with TB in England were born outside the UK (TB incidence and epidemiology in England, 2021). The UK pre-entry TB screening programme is intended to reduce the importation of prevalent pulmonary TB among applicants for long term visas.

The programme screens new migrants from countries with a TB incidence of over 40 per 100,000 for active pulmonary TB before they can apply for a long term (more than 6 months) UK visa (UK tuberculosis technical instructions).

In 2021, it operated in 102 countries since replacing on-entry screening at UK airports in March 2014. It uses chest x-ray (CXR) based screening for active pulmonary TB carried out by appointed panel clinics, usually in the country of origin, with sputum cultures conducted for those with those with abnormal CXR considered to be consistent with TB.

The programme is commissioned by the UK Home Office. UKHSA TB Unit provides advice, training, clinic audits, and data and information to support the quality assurance and evaluation of the programme by UKHSA Border Health.

The full annual report of the pre-entry programme for 2021 will be published later in the year.

Outline of countries, clinics, and data receipts

This report presents data from 152 overseas clinics for the period between January 2014 and December 2021.

Table 3 describes the number of reported screens by country and the number of results received by UKHSA for 2021. By the closing date for analysis (31st December 2022) 478,392 screening records were received by UKHSA compared with 360,548 in 2019 and 340,623 in 2020. This increase suggests a genuine increase in numbers screened and not just a a post-pandemic rebound in 2021.

Sixty-four countries conduct TB screening through International Organisation of Migration (IOM) clinics and 39 countries by non-IOM clinics. Only Russia employs both IOM and non-IOM clinic screening (Table 8 of the TB prevention in England, 2021 data set).

50.1% of results were from IOM clinics and 49.9% from non-IOM clinics. In 2021, screening results were not reported for 10% of screens in India and 52.6% of screens in China.

In 2021, the highest proportion of people screened were in India (25.5%), followed by Nigeria (17.7%) and then China (11.8%) (Table 3). The number and proportion of applicants from China was decreased compared with 2020, when 87,573 (25.7%) of reported screens were conducted in China. The top 10 countries accounted for 86.6% of applicants screened with reported results.

To estimate the likely proportion of total missing screen reports, we calculated the number of screens reported compared with numbers of eligible visa applications recorded. We estimate that approximately 29% of screens in 2021 may not have been reported (Entry clearance visas outside of the UK data set) However, people applying for visas might not proceed with TB screening and in some instances, people are screened by clinics but do not go on to apply for visas. Hence it is not possible to accurately match the number of reports received to the number of visa applications.

Table 3. Number of reported screening episodes and records received by UKHSA by country of screening, 2021

Country of screening	IOM/non-IOM	Applicants screened (as reported by the clinic)	records received by UKHSA	% of records received by country out of total received
India	Non-IOM	135,525	121,857	25.5
Nigeria	IOM	84,754	84,754	17.7
China	Non-IOM	119,347	56,562	11.8
Hong Kong	Non-IOM	Unknown	47,682	10.0
Pakistan	IOM	42,001	42,001	8.8
Bangladesh	IOM	20,269	20,269	4.2
South Africa	IOM	11,244	11,244	2.4
Philippines	IOM	10,524	10,524	2.2
Ghana	IOM	10,487	10,487	2.2
Sri Lanka	IOM	8,704	8,704	1.8
Nepal	IOM	8,670	8,670	1.8
Thailand	IOM	5,931	5,931	1.2
Zimbabwe	IOM	5,790	5,790	1.2
South Korea	Non-IOM	4,815	4,815	1.0
Other	Non-IOM	Unknown	7,798	1.6
Other	IOM	31,304	31,304	6.5
Total	Both	499,365	478,392	100.0

Table is ordered by frequency of screening records received.

TB case detection by the programme

During 2021, 371 people with confirmed or probable active tuberculosis were detected through pre-entry screening, giving an overall detection rate of 77.6 per 100,000 applicants.

The proportion of abnormal CXR results reported and the proportion of these with a reported sputum culture result and the total number of individuals detected as having confirmed or probable TB by country for 2021 along with TB detection rate is reported in Table 9 of the TB prevention in England, 2021 data set and for 2018 to 2020 combined in Table 10 of TB prevention in England, 2021.

In 2021 the percentage of records with abnormal CXR results consistent with TB ranged from 0.6% in Nigeria to 6.2% in Philippines. The proportion of abnormal CXR records with a reported sputum result was 65.8%. The number of people with chest x-ray abnormalities consistent with TB that had sputum results reported was lower in 2021 compared with the average between 2018 to 2020 (77.9%). Nearly all missing data was from non-IOM clinics, with proportion missing ranging from 92.6% for India to 78.8% for Hong Kong.

The proportion of individuals confirmed as having TB out of all individuals detected with possible or probable TB increased in 2021 at 67.4% compared with an average of 51.1% between 2018 and 2020 (Tables 9 and 10 of the TB prevention in England, 2021 data set).

In 2021, 34.5% of all individuals with TB detected through the programme were from India compared with the previous 3-year average of 42.4%. In 2021 the majority of these individuals from India (86%) were not confirmed with a reported sputum culture and were determined as probable TB cases (see the methodology and definitions section for details), compared with the previous 3-year average of 91% probable TB cases for India.

Figures 11a and 11b shows the number of people with active TB disease detected and the TB detection rate for all countries in the program from 2014 to 2021. In 2021 the TB detection rate decreased by 31.3% from 113.0 per 100,000 in 2020, although the number of people detected was similar. Over the whole period the detection rate decreased in 2015 and 2016 from the 2014 high of 168.4 per 100,000 then stabilised until the current decrease in 2021.

Figure 11a. Number of people with active TB disease detected between 2014 and 2021 in all screening countries

Figure 11b. TB detection rate between 2014 and 2021 in all screening countries

Culture confirmation and drug susceptibility results

TB culture and drug susceptibility testing (DST) is a mandatory requirement under the UK tuberculosis technical instructions. Of 250 people with confirmed TB, 213 (85.2%) were culture confirmed. DST results were available for 190 out of 213 positive cultures (89.2%) (Table 4). Most isolates were sensitive to all first-line drugs with 4 isolates with rifampicin resistance (RR) or multi-drug resistant TB (MDR-TB).

Table 4. Drug susceptibility testing of people with TB, 2021

Drug susceptibility category	N	% Total
Sensitive to all first line drugs	172	90.5
Resistant to one first-line drug, other than isoniazid and rifampicin	4	2.4
INH-R but not RR-TB or MDR-TB	7	3.7
Resistant to 2 or more first-line drugs (but not RR or MDR)	3	1.6
Rifampicin resistant (RR) or multidrug resistant (MDR) TB	4	2.0
Total	190	100.0

Action plan indicator 2: Reduce the proportion of people notified with TB in those born outside of the UK in whom TB occurs within 5 years of entry

The target for this indicator is a 5% reduction per year compared with a baseline of the average proportion from 2017 to 2019.

Figure 12 is a bar chart that shows the proportion of people born outside of the UK who are notified with active TB within 5 years of entry to the UK (action plan indicator 2). The average proportion for 2017 to 2019 was 29.1% and increased in both 2020 and 2021 to 32.3% in 2021.

Figure 12. Proportion of TB notifications in England occurring within 5 years of entry to the UK for all countries of birth outside of the UK

Reductions in this indicator require both prevention of people entering the UK with active TB by the pre-entry screening programme and the prevention of the later development of active TB by reactivation of latent TB infection in people entering the UK from high incidence countries. Pre-entry screening only detects prevalent active pulmonary disease. Detection and treatment of latent infection can also prevent the development of non-pulmonary TB, which is more common in the non-UK born population than in the UK -born.

For people notified with TB in England through NTBS, routes of entry (i.e. through long-term visa, short term visas or through undocumented or asylum seeker routes are not available or poorly recorded in NTBS. Therefore it is not possible to determine if individuals would have been eligible for pre-entry screening or not.

Recommendations

These recommendations are linked to the corresponding priorities in the TB action plan for England, 2021 to 2026.

Recommendation 1

UKHSA should continue to monitor and report annually on contact tracing. This should include a review of the indicator ‘90% target of a minimum of 5 close contacts’ who are identified and screened given the findings in this report and changes in work patterns and locations following the COVID-19 pandemic.

Recommendation 2

UKHSA should develop and publish national contact tracing evidence-based guidance and toolkits for TB services to improve data collection on the number of contacts screened and their outcomes.

Recommendation 3

UKHSA and NHSE should work closely with programme providers and commissioners to continue to support the recovery of the LTBI screening programme for eligible migrants from the effects of the COVID-19 pandemic to increase the number of eligible migrants tested and treated.

Recommendation 4

UKHSA and NHSE should work closely with programme providers and commissioners to improve data capture and completeness on treatment completion data from the LTBI programme in line with TB action plan objectives

Recommendation 5

UKHSA should develop modelling to understand the effects of changing migration patterns on the numbers and rates of TB notifications in individuals within 1 and 5 years of UK entry

Methodology and definitions

Contact tracing

Close contacts include individuals who have prolonged and frequent contact with persons infected with infectious TB and can include household contacts or frequent visitors to the home. This data is derived from the National Tuberculosis Surveillance System (NTBS).

This report will be the first to report on contact tracing information of persons notified with TB and will serve as a baseline for future publications.

TB notifications

People who are diagnosed with TB in England, Wales and Northern Ireland must be notified through NTBS. This report only includes data for individuals with TB who are resident in England or are treated in England (including individuals who are homeless or visiting from abroad).

Only individuals with disease caused by Mycobacterium tuberculosis complex (MTBC) are reported. Individuals were denotified and removed from the data set if the infective agent was identified as non-MTBC or M. bovis Bacillus Calmette-Guerin (BCG) subspecies.

Data production

In 2021, NTBS was launched and replaced 2 historical surveillance systems:

1. the Enhanced Tuberculosis Surveillance system (ETS)
2. the London TB Register (LTBR)

Data sets from 2018 onwards were extracted from ETS and LTBR and were merged with NTBS following a series of data migrations between July and December 2021. Data reported here were obtained from the merged data sets (NTBS, ETS, LTBR) and the final extract was on July 12 2022.

Data cleaning to improve data quality

Denotifications

People with BCGosis, on chemoprophylaxis for latent TB infection or with a non-tuberculous mycobacterial infection who were notified in error were identified using comments fields, and denotified. People with culture confirmed TB who had been denotified were queried with clinics, and lab contaminations were removed, or people were renotified if they were found to have been denotified in error.

In addition, a probabilistic matching process was carried out for notifications between January 2020 and December 2021 to identify people with more than one notification within a 12-month period. Identified duplicates were denotified with any missing information transferred from the duplicate to the original notification.  

Geography

The postcode field (used to map postcodes to geographic areas) was cleaned by identifying invalid postcodes based on matching to the May 2022 Postcode Directory from ONS. Where cleaning was necessary, the correct postcode was identified using the address fields.

For people who were homeless or who had a residence outside the UK, but were notified in England, the postcode of the clinic or hospital at which they were treated was assigned to the notification. For people with no postcode or treatment clinic or hospital, the local authority and UKHSA centre were updated using the local authority field recorded based on the area that the notifying case manager was located in.

UKHSA centre was derived from UKHSA region of residence based on the individual’s residential postcode. If missing, UKHSA centre in which treatment occurred (most recently, as care may have been transferred) was used, for example if a person had no fixed abode. 

Site of disease

The site of disease was reclassified to pulmonary if a positive sputum smear (microscopy) sample was recorded or if a positive culture was grown from a pulmonary laboratory specimen. People with laryngeal TB were included in pulmonary breakdowns, and people with miliary TB were included in both pulmonary and extra-pulmonary breakdowns. Site of disease for people with culture confirmation was reclassified based on the site in the body from which the specimen was taken. Site of disease classifications were also updated using the free text field for site of disease.

Social risk factors including prison and asylum status

The presence or absence of the social risk factors (current or a history of drug misuse, alcohol misuse, homelessness, prison, mental health and asylum status; including if remanded in an immigration detention centre) were updated from missing or unknown if relevant information was found in the free text comments fields within NTBS.

Homelessness was updated to ‘yes’ if mentioned in the comments fields or if the address given was ‘no fixed abode’ or a shelter or hostel for homeless people was named.

Prison (current or in the past) was updated to ‘yes’ if mentioned in the comment’s fields, if HMP or a prison name was recorded as the address or if the residential postcode corresponded with a prison. Up until 2020, data on incident TB individuals reported to the Public Health in Prisons (PHiP) log were used to further identify people who had been imprisoned, but this was not conducted in 2021.

The immigration detainee variable was updated if the address given at notification, comments fields or occupation field showed the person to be an immigration detainee. The asylum seeker variable (newly introduced in NTBS) was updated as asylum seeker if recorded in the occupation field sub-category under ‘no occupation’.

For analysis, asylum seeker was then recoded as ‘yes’ if either asylum seeker variable or immigration detainee variable were ‘yes’. The asylum seeker variable was further updated so that all UK-born individuals with a missing value for this variable was updated to ‘no’.

Demographic characteristics

Sex is reported as male or female. Where missing from the raw data, it was derived from the name of the individual where names were unambiguous.

Age is derived from the date of notification and date of birth and calculated within NTBS on entering of data. Those with negative values were cross-referenced with other dates to resolve. Age groups were derived from the age at notification.

UK and non-UK born status occurs in the raw data. It was amended if missing and the country of birth indicated non-UK birth.

Entry to the UK is entered as year only by NTBS users. Time since entry is derived as year of notification minus entry year.

Reporting methodology

Individuals with TB are reported by area of residence and by calendar year of notification.

Outliers

One notified individual with pulmonary TB was excluded from the analysis as this was part of a national incident with a substantial number of contacts recorded, 126 in total.

Time periods

Contact tracing data is presented from 2018 with most other data presenting data from 2021. For TB action plan (2021 to 2026) indicators, data are presented from 2021 onwards, representing the first year after implementation of the previous TB Strategy 2015 to 2020.

Social risk factors and are presented from 2018 onwards, when more complete data collection started, and additional risk factors were collected. Similarly, contact tracing data are presented from 2018 onwards when more complete data collection started.

Geography

UKHSA centre was derived from UKHSA region of residence based on individual’s residential postcode. If missing, UKHSA centre in which treatment occurred was used, for example if a person had no fixed abode.

Data presented by UKHSA centres is presented in order of most individuals with TB in 2021.

Cleaned postcodes were assigned boundary layers and merged with boundaries for CCGs, ICB, upper tier local authorities (UTLA) and local authorities sourced from the Central Lookups Database within the UKHSA Data Lake which is managed by the Public Health Data Science (PHDS) team. These are available in the UKHSA layers of the map software (GIS).

Social risk factors

People with TB are reported as having at least one SRF (‘yes’) if any of the 6 social risk factors (current alcohol misuse, current or a history of homelessness, drug misuse, imprisonment, asylum seeker status and mental health needs) had ‘yes’ recorded. As a result, the denominator is all notifications. This assumes that people for whom no data were recorded for individual SRFs were a ‘no’ and may result in under-estimation.

Data for individual social risk factors reported are limited to those with recorded data, for example a ‘yes’ or a ‘no’. As a result, the denominators for these are smaller than all notifications due to missing data. If there is significant under-reporting of SRFs in those with missing data, this should result in a better estimate of the true proportion of the people with each SRF. However, if data is more likely to be recorded if the response is a ‘yes’ this could result in an over-estimates. This may be the case for the asylum seeker SRF.

Mental health is recorded by TB case managers and is based on their judgement if mental health concerns are likely to affect the person’s ability to adhere to treatment. This was added to surveillance in London UKHSA centre in 2018 and is a simple ‘yes’ or ‘no’ response. It was introduced nationally in 2021 with the introduction of NTBS. Here we report this as the person has need of support for mental health and therefore has ‘mental health needs’.

Asylum seeker status and immigration removal centre were added to national surveillance as discrete variables in 2020. Prior to this, ‘asylum seeker’ status was extracted from free-text comment fields and user entered values within occupation (LTBR). As a result, more complete data on this exposure is assumed from 2020 to 2021 compared with previous years.

Alcohol misuse is as recorded by case managers and is based on their judgement if current alcohol misuse is likely to affect adherence to treatment.

History of drug misuse, homelessness and prison are self-reported by individuals and are first asked as a ‘yes’ or ‘no’ response and then with additional information on duration; as current, within last 5 years or more than 5 years ago. Unless indicated otherwise, analyses here present these SRFs as ‘yes’ if either history of, or a duration value, was recorded.

LTBI

Enhancement of the LTBI data sets

To improve the completeness of patient identifiable information and the accuracy of the data set, the LTBI data set was matched to SPINE and Flag4 data received from NHS Digital on new migrants. Where no NHS number was available, the forename, surname and date of birth were used to complete this field.

Number of people tested for LTBI

Where an individual has more than one positive or negative test result, the first result is included. Test results for individuals with more than one inconclusive result are retained in the total number of tests. LTBI test results that were reported as ‘unprocessed’ or ‘rejected’ were excluded from the data set.

Due to incomplete primary care testing data returns, UKHSA uses lab data to estimate the number of tests in CCGs operating a primary care-based model. Lab data does not contain eligibility criteria such as country of birth, or time spent in a high incidence country and may therefore represent an overestimation of eligible testing.

LTBI cohort of people known to have completed treatment

The maximum (last) IGRA date reported for each CCG was extracted. Only positive test results were included in the analysis. People who had their treatment discontinued for reasons such as pregnancy were excluded from this cohort. Of this cohort, the number of people who are known to have completed treatment are those who reported a date of treatment completion.

Data sources

As of 1 of July 2022, CCGs were replaced by the Integrated Care Systems (ICSs) model as implemented by the Health and Care Act 2022. Therefore this report presents data using the CCG healthcare model. The CCG change to corresponding ICB can be accessed in Table 11 of the TB prevention in England data set.

Flag 4 data, also known as Type 4 GP Registration Data, is used to identify individuals who have registered with a GP service within a specified period under the CCGs participating in the LTBI programme. This data is derived from the Spine Demographic Service (SDS) on a quarterly basis by NHS Digital and is released to the UKHSA TB team via a secure encrypted user interface.

The data is used to identify and invite the eligible migrant population for LTBI screening by the TB services under these CCGs. A select few services choose other methods to derive newly registered patients, however, 26 out of the 31 providers in the programme are reliant on Flag4 data to carry out core programmatic screening. Please note out of the 26 CCGs receiving Flag4 data, 2 CCGs (NHS Herts Valley CCG and NHS Cambridgeshire and Peterborough CCG) only receive aggregate numbers and were therefore not included in the analysis for Figure 8.

Pre-entry screening

Data collection

This report presents data collected from IOM and non-IOM clinics. IOM data was collected by IOM panel physicians, entered via a secure web-based IOM system and collated by the central office in Manila. This data was then securely transferred to UKHSA. Data from non-IOM providers was collected by the clinics, collated via the Home Office UKVI unit and securely transferred to UKHSA.

Data from IOM clinics was updated via their web-based portal prior to submission to UKHSA. Overall, 43.7% (45 out of 103) non-IOM clinics sent sputum culture updates and line lists of confirmed TB individuals in 2021 resulting in incomplete case ascertainment.

Data cleaning and analysis

Data was cleaned, validated and missing values completed where possible. Where possible, discrepant examination dates were deduced from other dates such as issue date of medical certificate. Whenever possible, missing values were deduced from other variables. Variables from IOM and non-IOM data were harmonised and merged into a common data set.

Non-IOM clinics were requested to submit an annual Clinic Audit which had the total number of applicants screened by clinics for the year e.g., 2021 and a line list of any applicants diagnosed with TB in that particular year. The total number screened per clinic was used to check if we had received all records from a clinic while the line list of individuals was compared to the number of individuals at a particular clinic.

A person with confirmed TB met the following criteria: had an abnormal chest x-ray consistent with TB and a positive sputum culture result or positive culture result in the absence of a valid CXR result (for example in pregnant women or young children).

In the absence of sputum test confirmation, TB was also confirmed if the following were documented:

• a clinician’s judgement that the patient’s clinical and/or radiological signs and/or symptoms are compatible with tuberculosis, AND
• a clinician’s decision to treat the patient with a full course of anti-tuberculosis therapy

In the absence of reported sputum culture results (culture results were pending or missing), probable TB status was assigned if a person had an abnormal CXR consistent with TB and TB was reported as suspected and or a TB clearance certificate was not issued due to TB-related matters.

Data from the period between January and December 2021, as received by 31 December 2022 was used in this report. Trends were reported for data for the period January 2014 to December 2021.

For people born outside the UK and diagnosed with TB after entry, only entry year was available and a proxy entry date of 2nd July of each year was used. Only people that entered within a calendar year were compared to those diagnosed with TB abroad by the UK pre-entry TB screening programme from these countries in the same year.

Data from the Home Office was used to estimate the number of applicants eligible for pre-entry TB screening.

Clean data was imported into Stata v.17 (Statacorp LP, College Station, TX, USA) which was used for all statistical analyses. Graphs and tables were created with MS Excel 2016 and exported to MS Word (Microsoft Corp, Redmond, WA, USA).

Outline of countries, clinics, and data receipts

Sixty-four countries employ TB screening through IOM (International Organisation of Migration) clinics and 39 countries by non-IOM clinics. Only Russia employs a mix of IOM and non-IOM clinic screening (Table 8 TB prevention in England, 2021 data set. IOM data is collected by IOM panel physicians, entered via a secure web-based IOM system, and collated by the central IOM office in Manila. This data is then securely transferred to UKHSA. Data from non-IOM providers is collected by the clinics, collated via the UK visa and immigration (UKVI) at the Home Office and securely transferred to UKHSA.

Hong Kong BN(O) visa holders were allowed to undergo post-entry TB screening in the UK in late 2020 and the Hong Kong BN(O) visa scheme was introduced in January 2021. This allows visa holders to live and work or study in the UK and a path to full British citizenship. Hong Kong is included in the pre-entry scheme but due to the worsening security situation, screening for these visa holders was allowed post-entry at designated clinics in the UK. Analysis of this data will be presented in the separate detailed Pre-entry TB screening report.

Statistical methods

Confidence intervals

95% confidence intervals are model derived and were calculated using assumptions of the Poisson distribution for rates and the binomial distribution for proportion.

Software packages

All statistical analysis was carried out using Stata SE 17.0

Glossary

95% confidence interval

In this report, model derived 95% confidence intervals (CI) are often presented alongside percentages and rates. For example, the percentage of TB notifications with pulmonary disease is 52.7% (95% CI 51.3 to 54.2%).

In layman terms, this can be loosely interpreted as that we have 95% confidence that the true but unknown value of this percentage in the population lies within the range of 51.3% to 54.2%. 

Pulmonary TB

A person with pulmonary TB is defined as having TB involving the lungs and/or tracheo-bronchial tree, with or without extra-pulmonary TB diagnosis. In this report, in line with the WHO’s recommendation and international reporting definitions, miliary TB is classified as pulmonary TB due to the presence of lesions in the lungs, and laryngeal TB is also classified as pulmonary TB.

Contact tracing

Contact tracing is the identification and screening of close contacts of persons identified with infectious TB. Contacts include any person who has been in close contact with a person infected with active pulmonary or laryngeal TB and usually includes all household members and frequent visitors to the home.

Clinical Commissioning Groups

Clinical commissioning groups (CCGs) are clinically led statutory NHS bodies responsible for the planning and commissioning of primary and secondary health care services.  

International migrant

An international migrant is classified as the movement of a person across international borders to seek temporary or permanent residence in another country.

Flag 4

The Flag 4 is a classification made for a person who has resided outside the UK for at least 3 months prior to their registration with a new GP, or who has previously been resident in the UK but has lived outside the UK for a period of 3 months and is limited to migrants aged 16 to 35 years.

The data contains patient information such as GP registration code, NHS number, date of Type 4 registration, GP practice code of T4 registration, TP practice name of T4 registration, place of birth, current GP practice code, current GP name, gender, date of birth, full name, patient’s current address.

Flag 4 records indicate international in-migrants who register with an NHS GP. This data is derived from the Spine Demographic Service (SDS) on a quarterly basis by NHS Digital and is released to the UKHSA TB team via a secure encrypted user interface.

LTBI

Latent TB infection (LTBI) is the dormant, non-infectious form of Mycobacterium tuberculosis. Persons with LTBI do not feel sick or have any TB-related symptoms but can develop active TB over time.

Home Office

The Home Office is a government department responsible for immigration, security, and law and order.

UKVI

UK Visas and Immigration is a division of the Home Office responsible for making the decision of who has the right to visit or stay in the country, with a focus on national security.

IOM clinics

The International Organization for Migration (IOM) is one of 150 country inter-governmental offices responsible for migration as part of the United Nations System. IOM clinics are commissioned by the UK Visa and Immigration Home Office to provide screening to migrants for active TB and who have lived in a country with a TB incidence of 40 per 100 000 for 6 months or longer.

Non-IOM clinics

Non- IOM clinics, are clinics which fall outside of the realm of IOM, and are commissioned by the UK Visa and Immigration Home Office to screen individuals for active TB and who have lived in a country with a TB incidence of 40 per 100 000 for 6 months or longer.

Social risk factor

Social risk factors for TB include current alcohol misuse, current or history of homelessness, current or history of imprisonment, current or history of drug misuse, current mental health needs, or current status as an asylum seeker or detainee in an immigration removal centre. Please see relevant section under reporting methodology for further details of these variables.

Multi-drug resistant TB (MDR TB)

Multi-drug resistant TB (MDR TB) is defined as resistance to at least isoniazid and rifampicin, with or without resistance to other drugs.

INH resistant

TB that is resistant to isoniazid, a first-line anti-TB drug, and not other drugs.

Monoresistant to a drug other than INH

Resistance to a first-line treatment drug other than INH, for example, ethambutol.

Pansensitive

Fully sensitive to all first line drugs, for example, isoniazid.

Poly-drug resistant

Poly-drug resistance refers to resistance to 2 or more first-line drugs but not to both isoniazid and rifampicin.

RR TB

Resistant to rifampicin, a first-line drug, and not other drugs.