Official Statistics

Sexually transmitted infections and screening for chlamydia in England: 2024 report

Updated 10 June 2025

Correction notice

This report was corrected on 10 June 2025 after editorial errors were found in ‘Table 2a. Chlamydia tests among young women aged 15 to 24 years by test setting, 2023 and 2024, England’, which contained duplicated data from Table 2b. This has now been corrected.

All other data accompanying the report is correct and remains unchanged.

Main points

This report provides a descriptive analysis of data on sexually transmitted infection (STI) diagnoses and screening for chlamydia in England up to the end of December 2024. It focuses primarily on the changes between 2023 and 2024 and also contains some trend data from 2015 to 2024. Data on STI tests and diagnoses between 2015 and 2024 is available in the accompanying data tables and slide set as well as the Sexual and Reproductive Health Profiles, which also include data at regional and upper and lower tier local authority levels.

Among people in England:

• infectious syphilis diagnoses increased 1.7% from 9,375 in 2023 to 9,535 in 2024; considering all syphilis diagnoses, including late stage or complications such as ocular and otosyphilis, diagnoses increased 4.6% from 12,456 in 2023 to 13,030 in 2024
• gonorrhoea diagnoses decreased 15.9% from 85,370 in 2023 to 71,802 in 2024
• chlamydia diagnoses decreased by 13.0% from 194,143 diagnoses in 2023 to 168,889 diagnoses in 2024
• first episode genital warts diagnoses decreased 4.3% from 26,193 in 2023 to 25,056 diagnoses in 2024
• new STI diagnoses decreased 8.8% from 399,947 in 2023 to 364,750 in 2024
• the diagnosis rates of STIs remain greatest in young people aged 15 to 24 years; gay, bisexual and other men who have sex with men (GBMSM); and some minority ethnic groups

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

• there was a 10.7% decrease in the number of chlamydia tests carried out, from 673,102 in 2023 to 601,295 in 2024
• there was a decrease of 18.0% in the number of chlamydia diagnoses, from 64,802 in 2023 to 53,166 in 2024; test positivity also decreased (from 9.6% in 2023 to 8.8% in 2024)

Overall trends

While this report primarily focuses on the changes between 2023 and 2024, 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. Concurrent with this period of disruption, the numbers of consultations, sexual health screens and STI diagnoses in 2020 and 2021 were lower than preceding years, which should be considered when assessing trends that span this period.

Between 2023 and 2024 there was an overall decrease in the number of consultations (face to face, telephone or online) delivered by SHSs in England (2.7% decrease from 4,630,665 in 2023 to 4,505,785 in 2024). The pattern varied by mode of consultation. The number of face-to-face consultations increased (3.1%, from 2,326,437 in 2023 to 2,398,259 in 2024) while the number of online consultations decreased (5.2%, from 1,975,983 in 2023 to 1,873,157 in 2024), as did the number of telephone consultations (28.6%, from 328,245 in 2023 to 234,369 in 2024).

Of all consultations (4,505,785) in 2024, 53.2% (2,398,259) were delivered face to face, 41.6% (1,873,157) via the internet and 5.2% (234,369) via telephone. Of all consultations, 51.8% (2,334,422) were by women who have sex with men, 19.6% (885,612) were by heterosexual men, 15.7% (711,781) were by GBMSM and 0.6% (30,806) 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 (diagnostic tests for one or more of chlamydia, gonorrhoea, syphilis and HIV) has remained relatively constant (2,380,498 in 2023 compared to 2,367,853 in 2024) (Figure 1). The largest proportion of screens (45.9%, 1,083,332) were by women who have sex with men. Further, 22.5% (533,660) were by heterosexual men and 17.5% (415,029) were by GBMSM and 0.7% (15,803) were by women who have sex with women.

Compared to 2023, the number of new STI diagnoses decreased by 8.8% (399,947 in 2023 to 364,750 in 2024). The most commonly diagnosed STIs in 2024 were chlamydia (46.3% of all new STI diagnoses, 168,899), gonorrhoea (19.7%, 71,802), first episode genital herpes (7.6%, 27,867), and first episode genital warts (6.9%, 25,056).

Figure 1. Number of new STI diagnoses and sexual health screens [note 1] among England residents accessing sexual health services, 2015 to 2024

Sources: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems.

Note 1: sexual health screens – 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.

Between 2023 and 2024 there was a decrease in the number of gonorrhoea diagnoses (15.9%, from 85,370 to 71,802), but an increase in infectious syphilis (primary, secondary and early latent stages) diagnoses (1.7%, from 9,375 to 9,535) (Figures 2a and 2b). The number of gonorrhoea diagnoses in 2024 is similar to the number reported in 2019 (71,113), while the number of syphilis diagnoses was the largest annual number reported since 1948.

Figure 2a. Number of new diagnoses of selected STIs (chlamydia, gonorrhoea and genital warts) among England residents accessing SHSs, 2015 to 2024

Figure 2b. Number of new diagnoses of selected STIs (genital herpes and syphilis) among England residents accessing SHSs, 2015 to 2024

Different scales are used on the vertical (y) axes in Figures 2a and 2b.

Sources: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems.

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.

There was an increase in infectious syphilis diagnoses among heterosexual men (23.8%, from 1,115 to 1,380) and numbers remained relatively constant for women who have sex with men (a 1.0% increase, from 822 to 830) and women who have sex with women (60 diagnoses in both 2023 and 2024) while among GBMSM the number of syphilis diagnoses decreased slightly (1.6%, from 6,435 to 6,330) (Figure 3). However, taking into account all diagnoses of syphilis, including late stage or complications such as ocular and otosyphilis, there were an additional 850 diagnoses amongst women who have sex with men, 931 diagnoses among heterosexual men and 1,172 diagnoses among GBMSM.

Figure 3. Number of diagnoses of syphilis among England residents accessing SHSs, 2015 to 2024

Source: Data from routine returns to the GUMCAD STI Surveillance Systems.

Note 6: includes infectious syphilis and late stage and complications of syphilis.

Note 7: includes diagnoses of primary, secondary and early latent syphilis.

Note 8: 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.

Diagnoses of chlamydia (in all age groups) have decreased 13.0% (from 194,143 in 2023 to 168,889 in 2024) (Figure 2a). The trends in chlamydia in young people are presented in the section of this report on the National Chlamydia Screening Programme (NCSP). Diagnoses of first episode genital herpes increased 3.5% (from 26,920 to 27,867) between 2023 and 2024, but remained lower than in 2019 (34,464). Diagnoses of first episode genital warts decreased (4.3%, from 26,193 to 25,056) between 2023 and 2024. This decrease was largely among those aged 24 years and under most of whom will have direct or indirect protection against the human papillomavirus (HPV) strains that commonly cause genital warts through the adolescent HPV vaccination programme.

Trends in diagnoses of STIs since 2015 are presented in Appendix Figures A2a to A2d and Table 1 of the accompanying data tables. Data on HIV testing and diagnoses is published separately on GOV.UK.

Populations with greater sexual health needs

Ethnic minority groups

While more STIs are diagnosed among people of White ethnicities, some ethnic minority groups have disproportionately higher diagnosis rates. There were 97,636 (26.8% of 364,750) diagnoses of new STIs among people of Asian, Black, Mixed or Other ethnicity in 2024 (23,177, 42,302, 22,729, and 9,482 respectively). 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 Mixed and Asian ethnicities had similar numbers of new STI diagnoses (22,729 and 23,177 diagnoses respectively) but expressed as rates, people of Asian ethnicity had the lowest rates of STI diagnoses (427 new STI diagnoses per 100,000 people). People of Asian and Black ethnicity experienced increases (6.7% and 5.0%, respectively) in the diagnosis of new STIs, while all other ethnic groups experienced a decrease in new STI diagnoses (see Table 2 of the accompanying data tables).

Previous research has found that deprivation and geography, as well as age differences, gender identity and sexual orientation are associated with much of the disparity between ethnic groups. However, there remain unknown factors that impact the distribution of STIs among different population groups. Ethnic disparities in STI diagnosis rates are influenced by underlying socio-economic factors and the role they play in the structural determinants of health of the population. STI diagnosis rates by residential area-level deprivation are available in the slide set which accompanies this report.

Figure 4. Number of new STI diagnoses among England residents accessing sexual health services by ethnicity [note 9], 2024

Sources: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems.

Note 9: the ethnic categories above are as specified by the Office for National Statistics (ONS).

Gay, bisexual and other men who have sex with men

There were decreases in bacterial STI diagnoses amongst GBMSM between 2023 and 2024: gonorrhoea decreased 4.1% (40,701 to 39,046), chlamydia decreased by 10.5% (19,585 to 17,519) and infectious syphilis decreased 1.6% (6,345 to 6,330). Genital warts also decreased over the same period (6.0%, from 1,873 in 2023 to 1,760 in 2024), while genital herpes increased by 8.7% (from 1,882 in 2023 to 2,046 in 2024) (Figures 5a and 5b).

Figure 5a. Number of diagnoses of selected STIs (chlamydia and gonorrhoea) among GBMSM accessing sexual health services, 2015 to 2024

Figure 5b. Number of diagnoses of selected STIs (syphilis, genital warts and genital herpes) among GBMSM accessing sexual health services, 2015 to 2024

Different scales are used on the vertical (y) axes in Figures 5a and 5b.

Source: Data from routine returns to the GUMCAD STI Surveillance Systems.

Note 10: 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 11: due to incomplete reporting of some sexual orientation data in 2021, STI diagnosis numbers for GBMSM from 2021 presented in Figures 5a and 5b have been adjusted. Full details are provided in the ‘Technical note’ in the Appendix.

Note 12: includes diagnoses of primary, secondary and early latent syphilis.

Note 13: first episode.

In 2024, there was a 13% increase in cases of sexually transmitted shigellosis in England, from 2,052 in 2023 to 2,311 in 2024. In addition, there has been an increase in the number of Shigella spp. isolates that were extensively-drug resistant (XDR), and recent outbreaks of XDR shigellosis among GBMSM have highlight the concerns of limited effective treatment options.

Following the emergence of the international outbreak of mpox clade IIb in May 2022, which involved mainly, but not exclusively, GBMSM there were 3,553 diagnoses of mpox in 2022. This declined to 137 cases of mpox clade IIb in 2023 and 268 in 2024. Despite continuing and regular imports of mpox clade IIb, it is likely that case numbers during 2023 and 2024 remained substantially lower than those seen in 2022 due to high levels of vaccine protection suppressing transmission.

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 two-year pilot. From the pilot start in 2016 to the end of 2024, the reported data shows 32.3% of eligible attendees have received at least one dose of the HPV vaccine, and among those aged 25 and over (currently recommended to receive 2 doses) with a first dose recorded, 51.9% have received at least 2 doses. In 2024, 16,141 eligible GBMSM were vaccinated (one dose) (compared to 17,557 in 2023). A very small proportion of GBMSM (1.1% in 2024) have not accepted this vaccine when offered it. HPV vaccination may be under-reported (more details are available in the Quality and Methodology Information (QMI) report). Further information on the HPV vaccination schedule can be found in the Green Book.

Young people aged 15 to 24 years

Young people, particularly those aged 20 to 24 years, experience high diagnosis rates of the most common STIs, and this reflects the higher rates of partner change among this age group. Compared to 2023, the number of new STI diagnoses in 2024 among young people aged 15 to 24 years decreased by 18.5% (166,827 to 135,965). This is largely due to a 17.5% decrease in the number of chlamydia diagnoses (from 104,008 in 2023 to 85,757 in 2024) and a 36.3% decrease in the number of gonorrhoea diagnoses (from 30,045 in 2023 to 19,114 in 2024) (Figure 6). The change in chlamydia diagnoses is discussed further in the NCSP section of this report.

Figure 6. Number of gonorrhoea diagnoses by age group, 2015 to 2024

Source: Data from routine returns to the GUMCAD STI Surveillance Systems.

Note 14: 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 from September 2019. Therefore, in 2024 all young women aged 15 to 24 years would have been offered the quadrivalent vaccine when aged 12 to 13 years. In 2024, heterosexual men aged 15 to 18 years would have been offered the quadrivalent vaccine when aged 12 to 13 years; older heterosexual men would have only benefited from indirect protection from the quadrivalent vaccine (the Green Book, chapter 18a).

The rate of first episode genital warts diagnoses among young women aged 15 to 24 years decreased by 85.8% between 2019 and 2024 (from 280.2 to 39.9 per 100,000 population respectively). A decrease of 82.7% (262.7 to 45.5 per 100,000 population) was seen in heterosexual young men of the same age over the same period. A decrease of 64.5% (947.0 to 336.3 per 100,000 population between 2019 and 2024) was seen in GBMSM aged 15 to 24 years, which is likely due to protection from the adolescent vaccination programme, as well as vaccination of young GBMSM in SHSs.

Data on recent sex partners

This section presents data on diagnoses of gonorrhoea and syphilis and the number of recent sex partners reported by people attending face-to-face SHSs in 2024. In 2024, data on the number of recent (prior 3 months) sex partners was reported for 31.4% (753,152 of 2,398,259) of face-to-face attendances in 2024. This information is available from 2023 although not all services reported this data in 2023 and 2024. More details can be found in the QMI report.

Among all women, where sex partnerships were reported, gonorrhoea and syphilis were most frequently diagnosed among those with one recent sex partner (59.3%, 2,616 of 4,414 and 66.1%, 250 of 378, respectively).

Among heterosexual men, where sex partnerships were reported, gonorrhoea and syphilis were also most frequently diagnosed among those reporting one recent sex partner (48.6%, 2,733 of 6,105 and 53.0%, 331 of 625, respectively).

Lastly, among GBMSM, where sex partnerships were reported, gonorrhoea and syphilis were most frequently diagnosed in those reporting 2 or more sex partners (8,149 of 10,772 and 68.8%, 1,664 of 3,901, respectively).

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

Full data is reported in Table 9 of the accompanying data tables.

Data on symptomatic testing

This section presents the distribution of STI tests (any one or a combination of tests for chlamydia, gonorrhoea, syphilis, HIV, hepatitis A, hepatitis B, hepatitis C, Mycoplasma genitalium, mpox, or trichomoniasis) that were performed in people attending SHSs. The number of STI tests uses a different unit of analysis than the number of sexual health screens because STI tests considers tests for each STI separately, while sexual health screens is a composite measure of 4 tests routinely offered at SHSs. This information is available from 2023 although not all services reported this data in 2023 or 2024. More details can be found in the QMI report.

There were 8,572,853 STI tests in 2024. Among people of all gender identities and sexual orientations, 20.4% of all tests (1,745,696) were among symptomatic individuals and 68.3% (5,857,173) were among asymptomatic individuals; 11.3% (969,984) of tests had no associated information about symptoms.

Of the 4,288,482 STI tests that were part of an online consultation, 15.0% (641,638) were by symptomatic people and 82.5% (3,588,955) were by asymptomatic people. There were 4,284,371 tests conducted in a face-to-face setting, of which 25.7% (1,104,058) were by symptomatic people and 54.1% (2,318,218) were by asymptomatic people.

Of all tests by heterosexual men (1,954,356), the percentage of tests by symptomatic men at face-to-face consultations (32.2%, 332,146 of 1,029,272) was higher than online (14.0%, 129,166 of 925,084).

Of all tests by GBMSM (1,742,620), there was a higher percentage of tests by symptomatic men in face-to-face settings (15.7%, 151,616 of 960,981) than online (8.0%, 62,299 of 781,639).

Of all tests by women (4,197,862), there was a higher percentage of symptomatic tests in face-to-face settings (28.8%, 542,113 of 1,881,820) than online (18.4%, 426,976 of 2,316,042). The proportions were similar for both women who have sex with men and women who have sex with women. Full data is presented in Table 11 of the accompanying data tables.

National Chlamydia Screening Programme

In June 2021, the primary aim of the National Chlamydia Screening Programme (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 identity and at any age, remain unchanged.

This report relates to 2024, the third full calendar year during which proactive, opportunistic screening was recommended only for young women and other people with a womb or ovaries aged 15 to 24 years. 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 activity. The chlamydia detection rate is a Public Health Outcomes Framework (PHOF) indicator and UKHSA recommends that local authorities should be working towards a detection rate of at least 3,250 diagnoses per 100,000 young women aged 15 to 24 years.

In 2024, 601,295 chlamydia tests were carried out in England among young women aged 15 to 24 years, a decrease of 10.7% compared to 2023 (673,102 tests) (Table 1), and of 36.4% compared to 2019 (944,736 tests). There was a small decrease in test coverage (the number of tests divided by population multiplied by 100) among these young women, from 20.1% in 2023 to 18.0% in 2024.

There was a decrease of 18.0% in the number of diagnoses made from 64,802 in 2023 to 53,166 in 2024. This is 38.7% lower than the number of diagnoses recorded in 2019 (86,668). Test positivity in young women decreased slightly from 9.6% in 2023 to 8.8% in 2024 (Table 1). As a result, the detection rate decreased by 18.0% between 2023 and 2024 (from 1,937 per 100,000 population to 1,589 per 100,000 population) (Figures 7a and 7b).

Table 1. Chlamydia tests, diagnoses, testing coverage, test positivity and detection rate among young women aged 15 to 24 years, 2023 and 2024, England

Indicator	2023	2024	Percentage change
Total tests	673,102	601,295	-10.7
Total diagnoses	64,802	53,166	-18
Test positivity	9.6%	8.8%	-8.2
Coverage	20.1%	18.0%	-10.4
Detection rate (per 100,000 population)	1,937	1,589	-18

Figure 7a. Chlamydia testing coverage and test positivity among young women aged 15 to 24 years, 2015 to 2024, England

Figure 7b. Chlamydia detection rates among young women aged 15 to 24 years, 2015 to 2024, England

Different scales are used on the vertical (y) axes in Figures 7a and 7b.

Sources: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems.

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.

Note 16: UKHSA recommended Public Health Outcomes Framework (PHOF) detection rate indicator.

Between 2023 and 2024, there was a decrease of 11.3% in the number of chlamydia tests carried out among young men aged 15 to 24 years (from 275,717 in 2023 to 244,136 in 2024). Further data on chlamydia tests and diagnoses in young men is provided in Appendix Tables A2a to A2c, and data for young women and men is included in the NCSP data tables.

Characteristics of young women screened for chlamydia

In 2024, the number of chlamydia tests in young women aged 15 to 24 years was highest in those of White British ethnicity (305,892), followed by those of Other White ethnicity (27,895). Chlamydia diagnoses were highest in those of White British ethnicity (28,211), followed by those of Black African ethnicity, at 2,400 diagnoses.

Chlamydia test coverage was highest among young women of Black Caribbean ethnicity (38.4%, 14,628 out of 38,130), followed by those of Mixed White and Black Caribbean ethnicity (24.5%, 12,766 out of 52,195), compared to those of White British ethnicity (13.9%, 305,892 out of 2,203,830). Testing, diagnoses, coverage and detection rate data by disaggregated ethnicity is presented in Appendix Table A3.

The detection rate was highest among young women of Black Caribbean ethnicity (4,713 per 100,000 population), followed by those of Mixed White and Black Caribbean ethnicity (2,648 per 100,000 population), compared to those of White British ethnicity (1,280 per 100,000 population).

Chlamydia testing and diagnoses also differed by level of socioeconomic deprivation, as measured using the Index of Multiple Deprivation (IMD, a residential area-level measure of socioeconomic status). The first quintile (Q1) represents the most deprived 20% of lower super output areas (LSOAs, small geographical areas with 1,000 to 3,000 residents) and the fifth quintile (Q5) the least deprived 20% of LSOAs. Chlamydia test coverage in females was highest among those living in the most deprived quintiles.

In 2024, the chlamydia detection rate was highest in the most deprived quintile, at 2,005 per 100,000 population (Figure 8). The detection rate decreased across all quintiles between 2023 and 2024. Further data on chlamydia testing activity by deprivation quintile is included in the NCSP data tables.

Figure 8. Chlamydia detection rates among young women aged 15 to 24 years by IMD quintile [note 17], 2024, England

Sources: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems.

Note 17: NCSP data presented by IMD quintile is based on the location of residence of the person tested.

Testing service type

In 2024, most chlamydia tests in young women were provided by internet services (40.5%, 243,330 of 601,295 tests) and specialist SHS (26.4%, 158,691 of 601,295 tests).

Between 2023 and 2024, the number of chlamydia tests by young women in specialist SHSs decreased by 2.0% (from 161,851 to 158,691). There were also decreases in numbers of tests in non-specialist SHSs (11.8%, from 15,534 to 13,703) (Table 2a).

The number of tests conducted in a face-to-face setting among young women aged 15 to 24 years decreased by 6.6% between 2023 and 2024 (from 357,965 to 383,365). There was a 16.0% decrease in the number of tests conducted using self-sampling kits obtained via the internet between 2023 and 2024 (289,737 in 2023 and 2024 in 243,330) (Figure 9a). Find further information on the different types of testing service in the ‘Data sources’ section of the accompanying QMI report.

Diagnoses also decreased across all testing service types. In particular, there were more than 6,000 fewer diagnoses via internet services, a decrease of 22.3% from 2023 to 2024 (27,504 diagnoses in 2023 to 21,370 diagnoses in 2024) (Table 2b and Figure 9b.

Testing positivity has decreased across all testing service types, from 9.6% in 2023 to 8.8% in 2024 (Table 2c).

Table 2a. Chlamydia tests among young women aged 15 to 24 years by test setting, 2023 and 2024, England

Test setting	Number of tests in 2023	Percentage of total in 2023	Number of tests in 2024	Percentage of total in 2024	Percentage change 2023 to 2024
SHSs – specialist	161,851	24.0	158,691	26.4	-2.0
SHSs – non-specialist	15,534	2.3	13,703	2.3	-11.8
Internet	289,737	43.0	243,330	40.5	-16.0
GP	117,856	17.5	107,054	17.8	-9.2
Pharmacy	2,286	0.3	1,936	0.3	-15.3
Termination of pregnancy	5,274	0.8	4,745	0.8	-10.0
Unknown	7,107	1.1	6,446	1.1	-9.3
Other	73,457	10.9	65,390	10.9	-11.0
Total	673,102	100	601,295	100	-10.7

Table 2a was revised on 10 June 2025 to correct duplicated data.

Table 2b. Chlamydia diagnoses among young women aged 15 to 24 years by test setting, 2023 and 2024, England

Test setting	Number of diagnoses in 2023	Percentage of total in 2023	Number of diagnoses in 2024	Percentage of total in 2024	Percentage change 2023 to 2024
SHSs – specialist	21,224	32.8	18,672	35.1	-12.0
SHSs – non-specialist	1,910	2.9	1,573	3.0	-17.6
Internet	27,504	42.4	21,370	40.2	-22.3
GP	6,552	10.1	5,250	9.9	-19.9
Pharmacy	263	0.4	221	0.4	-16.0
Termination of pregnancy	508	0.8	374	0.7	-26.4
Unknown	492	0.8	421	0.8	-14.4
Other	6,349	9.8	5,285	9.9	-16.8
Total	64,802	100	53,166	100	-18.0

Table 2c. Chlamydia test positivity among young women aged 15 to 24 years by test setting, 2023 and 2024, England

Test setting	Test positivity 2023 (percentage)	Test positivity 2024 (percentage)
SHSs – specialist	13.1	11.8
SHSs – non-specialist	12.3	11.5
Internet	9.5	8.8
GP	5.6	4.9
Pharmacy	11.5	11.4
Termination of pregnancy	9.6	7.9
Unknown	6.9	6.5
Other	8.6	8.1
Total	9.6	8.8

Sources: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems.

Figure 9a. Chlamydia tests from internet and face-to-face testing among young women aged 15 to 24 years, 2015 to 2024, England

Figure 9b. Chlamydia diagnoses from internet and face-to-face services among young women aged 15 to 24 years, 2015 to 2024, England

Different scales are used on the vertical (y) axes in Figures 9a and 9b.

Sources: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems.

Note 18: 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.

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, the distribution of ages, ethnicities and levels of deprivation of the population, as well as 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 overall decrease in consultations at SHSs in England between 2023 and 2024, with more face-to-face consultations but fewer online and telephone consultations in 2024 compared to 2023. However, when compared to 2019 (the year prior to the COVID-19 pandemic), there were fewer face-to-face attendances in 2024. Online consultations made up 41.6% of all consultations in 2024. An appropriate mix of both face-to-face and online services may facilitate access to SHSs given evidence of inequality of use of online services and of some people finding it difficult to be tested for STIs using online services.

The number of sexual health screens provided by SHSs (for people of all ages) remained relatively stable between 2023 and 2024; there was an increase in the number of syphilis tests, but small decreases in the number of chlamydia and gonorrhoea tests. The changing patterns in STI diagnoses suggests a complexity of factors influencing the transmission of STIs amongst different populations.

Among young women aged 15 to 24 years, there was a reduction in chlamydia tests and diagnoses between 2023 and 2024; this was seen across all services, but largely due to a drop in online testing. There was a greater decrease in diagnoses than the decrease in testing and therefore a decrease in positivity. Through the NCSP, the offer of opportunistic chlamydia screening to sexually active young women 15 to 24 years old aims to prevent the harms of untreated chlamydia infection, including pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility.

There were fewer diagnoses of both syphilis and gonorrhoea among GBMSM in 2024; among heterosexuals, the number of syphilis diagnoses continued to increase. Following the large increase in gonorrhoea diagnoses in young people between 2021 and 2022, the number of diagnoses in young people aged 15 to 24 years has decreased.

In 2024, STIs continued to disproportionately impact GBMSM, people of Black Caribbean ethnicity, and young people aged 15 to 24 years.

Genital warts have continued to decrease in populations who have been offered HPV vaccination with a vaccine including protection against HPV types 6 and 11.

The inclusion of behavioural data with routine GUMCAD STI surveillance submissions from most SHSs since 2023, presented in this report and the accompanying data tables, allows for greater understanding of sexual 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) advised a targeted vaccination programme for gonorrhoea in SHSs using 4CMenB vaccine; eligible people will be offered the vaccine at SHSs from August 2025. Additionally, UKSHA 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 (doxyPEP) for the prevention of syphilis.

To address the increase in syphilis diagnoses in England, UKHSA published a Syphilis Action Plan in 2019 which focused 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. UKHSA also contributed to the National Institute for Health and Care Excellence (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, 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.

In 2024, UKHSA published the STI Prioritisation Framework, which is an evidence-based framework to inform local prioritisation decisions for STI control. It is rooted in a public health approach and supported by a set of guiding principles which are intended to help steer priority-setting for STI prevention and control within finite resources.

Data sources and methodology

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-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 sources and comprehensive methodological information can be found in the QMI report.

Appendix

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.

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.

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, 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 Figures A1a and A1b). However, this would have solely been due to an artefact of the incompleteness of the data.

Figure A1a. Adjusted and unadjusted number of new diagnoses of selected sexually transmitted infections among GBMSM accessing sexual health services, England, 2015 to 2024

Figure A1b. Adjusted and unadjusted number of new diagnoses of selected sexually transmitted infections among GBMSM accessing sexual health services, England, 2015 to 2024

Different scales are used on the vertical (y) axes in Figures A1a and A1b.

Source: Data from routine returns to the GUMCAD STI Surveillance Systems.

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.

Note 20: the number of STI diagnoses in GBMSM in 2021 was adjusted to account for incomplete reporting of some sexual orientation data.

Note 21: includes diagnoses of primary, secondary and early latent syphilis.

Note 22: first episode.

Additional analyses

Figures A2a to A2d shows the trends in the number of diagnoses of syphilis, gonorrhoea, genital herpes and genital warts, by women and men residing in England, 2015 to 2024.

Figure A2a. New diagnoses of syphilis by women and men among England residents accessing sexual health services, 2015 to 2024.

Figure A2b. New diagnoses of gonorrhoea by women and men among England residents accessing sexual health services, 2015 to 2024

Figure A2c. New diagnoses of genital herpes (first episode) by women and men among England residents accessing sexual health services, 2015 to 2024

Figure A2d. New diagnoses of genital warts (first episode) by women and men among England residents accessing sexual health services, 2015 to 2024

Different scales are used on the vertical (y) axes in Figures A2a to A2d.

Source: Data from routine returns to the GUMCAD STI Surveillance Systems.

Note 23: includes infectious syphilis and late stage and complications of syphilis.

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.

Tables A2a to A2c show chlamydia tests, diagnoses and positivity among young men aged 15 to 24 years by test setting, 2023 and 2024, England.

Table A2a. Chlamydia tests among young men aged 15 to 24 years by test setting, 2023 and 2024, England

Test setting	Number of tests in 2023	Percentage of total in 2023	Number of tests in 2024	Percentage of total in 2024	Percentage change 2023 to 2024
SHSs – specialist	90,696	33	89,208	36.5	-1.6
SHSs – non-specialist	6,421	2.3	5,556	2.3	-13.5
Internet	133,951	48.7	111,392	45.6	-16.8
GP	17,867	6.5	14,845	6.1	-16.9
Pharmacy	756	0.3	614	0.3	-18.8
Termination of pregnancy	14	0	48	0	242.9
Unknown	1,483	0.5	1,419	0.6	-4.3
Other	23,983	8.7	21,054	8.6	-12.2
Total	275,171	100	244,136	100	-11.3

Table A2b. Chlamydia diagnoses among young men aged 15 to 24 years by test setting, 2023 and 2024, England

Test setting	Number of diagnoses in 2023	Percentage of total in 2023	Number of diagnoses in 2024	Percentage of total in 2024	Percentage change 2023 to 2024
SHSs – specialist	15,112	42.3	13,651	46.4	-9.7
SHSs – non-specialist	1,076	3	837	2.8	-22.2
Internet	14,786	41.4	11,132	37.8	-24.7
GP	1,826	5.1	1,299	4.4	-28.9
Pharmacy	130	0.4	100	0.3	-23.1
Termination of pregnancy	2	0	9	0	350
Unknown	129	0.4	129	0.4	0
Other	2,688	7.5	2,281	7.7	-15.1
Total	35,749	100	29,438	100	-17.7

Table A2c. Chlamydia test positivity among young men aged 15 to 24 years by test setting, 2023 and 2024, England

Test setting	Test positivity 2023 (percentage)	Test positivity 2024 (percentage)
SHSs – specialist	16.7	15.3
SHSs – non-specialist	16.8	15.1
Internet	11	10
GP	10.2	8.8
Pharmacy	17.2	16.3
Termination of pregnancy	14.3	18.8
Unknown	8.7	9.1
Other	11.2	10.8
Total	13	12.1

Sources: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems.

Table A3 shows the number of chlamydia tests, diagnoses testing coverage and detection rate by disaggregated ethnic groups among young women in England.

Table A3. Chlamydia tests, diagnoses, testing coverage and detection rate by ethnicity among young women aged 15 to 24 years, 2024, England

Ethnicity	Total tests	Total diagnoses	Percentage coverage	Detection rate (per 100,000)
Asian	20,276	1,521	5.1	384
Bangladeshi	1,691	111	3	195
Chinese	3,466	365	7.8	818
Indian	6,121	352	6	347
Pakistani	3,350	191	2.6	149
Other Asian	5,648	502	8.8	780
Black	40,485	4,773	21.3	2,516
Black African	21,129	2,400	16.5	1,873
Black Caribbean	14,628	1,797	38.4	4,713
Other Black	4,728	576	20.2	2,463
Mixed	24,153	2,445	15.2	1,535
White and Asian	6,193	498	13.4	1,080
White and Black African	5,194	565	23.2	2,522
White and Black Caribbean	12,766	1,382	24.5	2,648
Other Mixed	8,754	875	22.7	2,269
Other	6,768	582	8.2	702
Any other ethnicity	6,768	582	8.2	702
White	337,029	30,858	13.8	1,264
White British	305,892	28,211	13.9	1,280
White Irish	3,242	307	20.6	1,950
Other White	27,895	2,340	12.5	1,051

Sources: Data from routine returns to the GUMCAD STI and CTAD Chlamydia Surveillance Systems.

Resources on the UKHSA website

Further STI data is available on the UKHSA STI annual data web page in the form of tables and a slide set.

Further data on chlamydia tests and diagnoses in adults aged 15 to 24 years is available on the UKHSA NCSP annual data web page.

Interactive tables, charts, and maps showing local-area STI data is available on the Sexual and Reproductive Health Profiles.

Provisional data on selected STIs is available on the STI quarterly surveillance reports: provisional data.

Further information on the GUMCAD STI and CTAD Chlamydia Surveillance Systems.

Further information on the Gonococcal Resistance to Antimicrobials Surveillance Programme (GRASP).

Further information on Mycoplasma genitalium Antimicrobial Resistance Surveillance (MARS).

Further information on trends in mpox.

Further information on trends in HIV diagnoses in the UK.

For the latest lymphogranuloma venereum (LGV) surveillance data for the UK.

For the latest guidance and data on Shigella spp.

For further information on pelvic inflammatory disease (PID).

Acknowledgments

Contributors to Official Statistics (in alphabetical order):

Anja Anderson, George Baldry, Carol Chatt, Shivani Chokupermal, Michelle Cole, Helen Corkin, Ubah Daahir, Srilaxmi Degala, Dhruv Desai, Kate Donohoe, Vicky Dowling, Stephen Duffell, Jon Dunn, Lynsey Emmett, Miranda Ferguson, Josh Forde, Giulia Habib Meriggi, Ana-Karina Harb, Catriona Harrison, Kate Houseman, Gareth Hughes, Kritika Jain, Danielle Jayes, James Johnson, Geraldine Leong, Clare Macdonald, Steph Migchelsen, Debbie Mou, Prarthana Narayanan, Shahin Parmar, Dawn Philips, Manchari Rajkumar, Kareem Abdul Rahman, Tika Ram, Andy Raynor, Cristina Santamaria-Plaza, Maria SuauSans, Suzy Sun, Alireza Talebi, Eliza Thomson, Hridhya Vijayan, Megan Walsh, Georgina Wilkinson, Brennan Winer.

Authors:

Stephanie J Migchelsen, Ubah Daahir, Clare Macdonald, Ana-Karina Harb, Lana Drisdale-Gordon, Stephen Duffell, Marta Checchi, Lucinda Slater, George Baldry, Hridhya Vijayan, Giulia Habib Meriggi, Tika Ram, Kate Soldan, Kate Folkard, Katy Sinka, Hamish Mohammed.

Citation

Stephanie J Migchelsen, Ubah Daahir, Clare Macdonald, Ana-Karina Harb, Lana Drisdale-Gordon, Stephen Duffell, Marta Checchi, Lucinda Slater, 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, 2024. June 2025, UK Health Security Agency, London

Further information and contact details

Contact information

For questions about this report, please contact GUMCAD@ukhsa.gov.uk

Official statistics

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 cchs@ukhsa.gov.uk 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 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.