Research and analysis

Spotlight on sexually transmitted infections in the South West: 2021 data

Updated 8 August 2024

Summary

Residents of the south-west have the lowest rates of sexually transmitted infections (STIs) among UK Health Security Agency (UKHSA)’s regions across England. However, there is notable variation across upper tier local authorities (UTLAs) and there is a considerable burden of disease across the region.

Just over 21,000 new STIs were diagnosed in South West residents in 2021, representing a rate of 371 diagnoses per 100,000 population. Rates by UTLA ranged from 230 new STI diagnoses per 100,000 population in North Somerset to 616 new STI diagnoses per 100,000 population in the City of Bristol. Overall rates of new STIs were broadly similar between men and women (342 and 364 per 100,000 residents, respectively). The number of new STIs diagnosed in South West residents decreased by 8% between 2020 and 2021.

Reductions in the numbers of 3 of the 5 major STIs were seen in:

• syphilis decreased by 32%
• gonorrhoea by 17%
• chlamydia by 12%.

Genital herpes increased by 10%, with new genital warts diagnoses remaining stable.

In June 2021, the National Chlamydia Screening Programme (NCSP) changed to focus on reducing the reproductive harm of untreated infection in young women. This led to a change in the recommended chlamydia detection rate indicator (DRI) included in the Public Health Outcomes Framework (PHOF).

UKHSA recommends that local authorities work towards the revised female-only PHOF benchmark DRI of 3,250 per 100,000 females aged 15 to 24 years. This report relates to 2021 data, for most of which the NCSP recommended an offer of screening to all sexually active young people aged under 25 years.

In 2021, the chlamydia diagnosis rate among South West residents aged 15 to 24 years was 1,079 per 100,000 residents.

Where gender and sexual orientation are known, gay, bisexual and other men who have sex with men (GBMSM) account for 14% of new STI diagnoses among South West residents diagnosed with a new STI (excluding chlamydia diagnoses reported via Chlamydia Testing Activity Dataset (CTAD) surveillance system (78% of those diagnosed with syphilis and 49% of those diagnosed with gonorrhoea). Among GBMSM, new diagnoses of all STIs fell between 2017 and 2021; between 2020 and 2021 syphilis (-24%) and gonorrhoea (-19%) declined, chlamydia (+1%) and genital warts (+5%) remained stable, with a notable increase in genital herpes (+40%).

STIs disproportionately affect young people. South West residents aged between 15 and 24 years accounted for 50% of all new STI diagnoses in 2021. A steep decline (94% decrease) has been seen between 2017 and 2021 in genital warts diagnosis rates in females aged 15 to 19 years. This follows the introduction in 2008 of vaccination against Human papillomavirus (HPV), the virus which causes genital warts, for females aged 12 to 13 years.

People of white ethnicity had the highest number of new STI diagnoses in 2021 at 16,282 (90% of all diagnoses). Despite less than 1% of new STIs being diagnosed in people of black Caribbean ethnicity, they have the highest rate (1,170 per 100,000) which is 4 times the rate seen in the white ethnic group, although not adjusted for age. Where country of birth was known, 88% of South West residents diagnosed with a new STI in 2021 (excluding chlamydia diagnoses reported via CTAD) were UK-born.

Following a sharp decrease in STI testing rates across the South West between 2019 and 2020 this has increased in 2021. Testing rates are now marginally higher in 2021 compared to 2017.

Conclusions

Following the disruptions in service delivery during the first year of the COVID-19 pandemic, the number of consultations at sexual health services (SHSs) increased between 2020 and 2021 and now exceeds the number reported in 2019. This provides evidence of a recovery in service provision, after the lifting of COVID-19 restrictions in the summer of 2021, partially driven by the continued widespread provision of online consultations.

The number of sexual health screens (for chlamydia, gonorrhoea, syphilis and HIV) in England also increased between 2020 and 2021, although the number of STI diagnoses remained stable. The increase in sexual health screens may be a result of built-up demand for SHSs as well as a return to pre-COVID-19 pandemic levels of social and sexual mixing and the substantial number of tests being accessed through online services (1 to 4).

It will remain important to continue to monitor and understand whether these changes have affected equity of access to SHSs (5, 6).

Chlamydia continues to account for the majority of STI diagnoses made in 2021, a large proportion of which are related to the NCSP. Screening rates for chlamydia have recovered gradually since the pandemic, with an increasing proportion of tests and diagnoses being made via internet services.

Although overall STI diagnoses rates remained similar between 2020 and 2021, there was an increase in bacterial STI diagnoses among GBMSM. STIs continue to show geographic and socioeconomic variation and disproportionately impact GBMSM, people of black Caribbean ethnicity, and young people aged 15 to 24 years.

UKHSA’s main messages

Providers and commissioners have an important role in communicating messages about safer sexual behaviours and how to access services.

Important prevention messages

Using condoms consistently and correctly protects against HIV and other STIs such as chlamydia, gonorrhoea, and syphilis and can prevent unplanned pregnancy.

Regular screening for STIs and HIV is essential to maintain good sexual health. Everyone should have an STI screen, including an HIV test, on at least an annual basis if having condomless sex with new or casual partners.

In addition:

• women and other people with a womb or ovaries under the age of 25 years who are sexually active should have a chlamydia test annually and on change of sexual partner
• GBMSM should have an annual test for HIV and STIs or every 3 months if having condomless sex with new or casual partners

HIV pre-exposure prophylaxis (PrEP) can also be used to provide protection to people at risk of HIV while HIV post-exposure prophylaxis (PEP) can be used after condomless sex if someone has potentially been exposed to HIV, to reduce the risk of contracting HIV. Both can be obtained from specialist SHSs.

People living with diagnosed HIV who are on treatment and have an undetectable viral load are unable to pass on the infection to others during sex. This is known as ‘Undetectable = Untransmittable’ or ‘U=U’.

Vaccination against mpox (monkeypox) virus, HPV, hepatitis A and hepatitis B will protect against disease caused by these viruses and prevent the spread of these infections:

• GBMSM can obtain the mpox, hepatitis A and hepatitis B vaccines from specialist SHSs; these vaccines are also available for other people at high risk of exposure to the viruses
• GBMSM aged 45 years and under can also obtain the HPV vaccine from specialist SHSs

SHSs are free and confidential and offer testing and treatment for HIV and STIs, condoms, vaccination, HIV PrEP, and PEP:

• online self-sampling for HIV and STIs is widely available
• information and advice about sexual health, including how to access services, is available at Sexwise and from the national sexual health helpline on 0300 123 7123

Charts, tables and maps

Figure 1. New STI diagnosis rates by UKHSA region of residence, England, 2021

Data sources: GUMCAD, CTAD

Figure 1 is a bar chart showing the rate of new STI diagnoses per 100,000 population by UKHSA region of residence. In 2021, the South West has the lowest rate (371.5 per 100,000) in England, whilst London has the highest rate (1,127.5 per 100,000).

Figure 2. Number of diagnoses of the 5 main STIs, South West residents, 2017 to 2021

Data sources: GUMCAD, CTAD

[note 1] Any increase in gonorrhoea diagnoses may be due to the increased use of highly sensitive nucleic acid amplification tests (NAATs) and additional screening of extra-genital sites in GBMSM.

Any decrease in genital wart diagnoses may be due to a moderately protective effect of HPV-16/18 vaccination.

Any increase in genital herpes diagnoses may be due to the use of more sensitive NAATs.

Increases or decreases may also reflect changes in testing practices.

Figure 2 shows trendlines for the number of diagnoses for the 5 main STIs among South West residents from 2017 to 2021. Chlamydia remained the most frequently diagnosed STI, even though the number of new chlamydia diagnoses decreased from 2017 (17,444) to 2021 (10,963). Syphilis remained the least frequently diagnosed STI, and number of new diagnoses continued to decrease between 2017 (281) and 2021 (261). Between 2017 and 2021, the number of diagnoses for the other 3 main STIs in the South West, also all decreased, genital warts (5,809 to 2,772), gonorrhoea (1,767 to 1,588) and genital herpes (2,667 to 1,964).

Figure 3. Diagnosis rates of the 5 main STIs, South West residents, 2017 to 2021

Data sources: GUMCAD, CTAD

See [note 1] above.

Figure 3 shows trendlines for diagnosis rates per 100,000 population for the 5 main STIs among South West residents from 2017 to 2021. Diagnosis rates decreased for all STIs in the South West between 2017 and 2021: syphilis (5.1 to 4.6 per 100,000), gonorrhoea (31.8 to 28.1 per 100,000), chlamydia (313.8 to 193.7 per 100,000), genital herpes (48.0 to 34.7 per 100,000), and genital warts (104.5 to 49.0 per 100,000). Chlamydia diagnosis rates remained higher than the other STIs, whilst syphilis remained the lowest over the 5 years.

Table 1. Percentage change in new STI diagnoses, South West residents

Diagnoses	2021	Percentage change 2017 to 2021	Percentage change 2020 to 2021
New STIs	21,023	-38%	-8%
Syphilis	261	-7%	-32%
Gonorrhoea	1,588	-10%	-17%
Chlamydia	10,963	-37%	-12%
Genital herpes	1,964	-26%	10%
Genital warts	2,772	-52%	1%

Data sources: GUMCAD, CTAD

See [note 1] above.

Table 1 shows the percentage change in new STI diagnoses in South West residents. In 2021, 21,023 new STI diagnoses were made, which is 8% lower than in 2020 and 38% lower than in 2017. The number of syphilis, gonorrhoea and chlamydia diagnoses made in 2021, decreased from the number seen in 2020 and 2017. The number of genital herpes and genital warts diagnoses in 2021 decreased compared to 2017 but increased compared to 2020. The biggest decrease in the number of diagnoses made between 2017 and 2021 was in genital warts (52% decrease) and between 2020 and 2021 was chlamydia (32% decrease).

Figure 4. Rates of new STIs per 100,000 residents by age group (for those aged 15 to 64 years only) and gender in the South West, 2021

Data sources: GUMCAD, CTAD

Figure 4 is a bar chart showing the rates of new STIs per 100,000 population in South West residents in 2021, by age group and gender. The highest rates for new STIs were in females aged 20 to 24 years (2,495.2 per 100,000) followed by males in the same age group (1,727.7 per 100,000). The lowest rates for new STIs were in those aged 45 to 64 years for both genders (131.6 per 100,000 and 63.3 per 100,000, for males and females, respectively).

Figure 5. Rates of gonorrhoea per 100,000 residents by age group [note 2] in the South West, 2017 to 2021

Data sources: GUMCAD

[note 2] Age-specific rates are shown for those aged 15 to 64 years only.

Figure 5 shows trend lines for rates of gonorrhoea per 100,000 population by age group in the South West from 2017 to 2021. Gonorrhoea rates remained consistently higher in those aged 20 to 24 years (155.4 to 126.3 per 100,000), and lowest in those aged 45 to 64 years (13.0 to 12.2 per 100,000). From 2017 to 2021, overall rates of gonorrhoea declined in all age groups, except in those aged 35 to 44 years where a small increase was exhibited (34.0 to 35.9 per 100,000). A peak in gonorrhoea rates was observed in 2019 across all age groups.

Figure 6. Rates of genital warts per 100,000 residents aged 15 to 19 years by gender in the South West, 2017 to 2021

Data sources: GUMCAD

Figure 6 shows trend lines for the rate of genital warts per 100,000 population of South West residents aged 15 to 19 years by gender from 2017 to 2021. Rates of genital warts decreased from 2017 to 2021 in both males (152.8 to 20.0 per 100,000) and females (345.9 to 20.3 per 100,000). Rates have historically been higher in females, however, from 2020 onwards the difference in rates between genders has decreased substantially.

Figure 7. Rates of new STIs by ethnic group per 100,000 residents in the South West, 2021

Data sources: GUMCAD, CTAD

Figure 7 is a bar chart showing the rates of new STIs by ethnic group in the South West in 2021 per 100,000 residents. The highest rate in 2021 was seen in the black Caribbean ethnic group (1,169.9 (95% Confidence interval (CI): 1,003.9 to 1,355.6) per 100,000), followed by the black African ethnic group (1,093.9 (95% CI: 966.1 to 1,233.8) per 100,000), all other ethnic groups combined (627.1 (95% CI: 593.2 to 662.5)) and then those from a white ethnic group (322.6 (95% CI: 317.7 to 327.6) per 100,000). The number of diagnoses in black Caribbean and black African ethnic groups is very small (see Table 2), with large confidence intervals for the rates.

Table 2. Proportion of South West residents diagnosed with a new STI by ethnicity, 2021

Ethnic group	Number	Percentage excluding unknown
White	16,282	90%
Black Caribbean	177	1%
Black African	265	1%
All other ethnic groups combined	1,274	7%
Unknown	3,025

Data sources: GUMCAD, CTAD

Table 2 shows the number and proportion of South West residents diagnosed with a new STI by ethnic group in 2021. The white ethnic group made up the greatest proportion of new STI diagnoses (90%), even though those of white ethnicity accounted for the lowest rate (Figure 7), whereas black Caribbean and black African ethnic groups only accounted for 1% of cases, respectively. All other ethnic groups combined accounted for 7% of new STI diagnoses in 2021.

Figure 8. Proportions of South West residents diagnosed with a new STI by world region of birth [note 3], 2021

Data sources: GUMCAD data only

[note 3] Data on country of birth is not collected by CTAD. All information about world region of birth is based on diagnoses made in specialist and non-specialist services, which report to GUMCAD.

Figure 8 is a bar chart showing the proportion of South West residents diagnosed with a new STI by world region of birth in 2021. UK-born cases constitute the highest proportion of South West residents diagnosed with a new STI (88%), followed by EU-born cases excluding the UK (6%). The smallest proportions of new STI diagnoses were those born in Sub-Saharan Africa, Caribbean, and Central and South America, which only accounted for 2% of cases, respectively. Cases born in all other countries accounted for 3% of total cases.

Figure 9. Diagnoses of the 5 main STIs among GBMSM [note 4], South West residents, 2017 to 2021

Data sources: GUMCAD data only

[note 4] Data on sexual orientation is not collected by CTAD. All information about GBMSM is based on diagnoses made in specialist and non-specialist services which report to GUMCAD.

GUMCAD started in 2009. Reporting of sexual orientation is less likely to be complete for earlier years, so rises seen may be partly artefactual.

Any increase in gonorrhoea diagnoses may be due to the increased use of highly sensitive NAATs and additional screening of extra-genital sites in GBMSM.

Any decrease in genital wart diagnoses may be due to a moderately protective effect of HPV-16/18 vaccination.

Any increase in genital herpes diagnoses may be due to the use of more sensitive NAATs.

Any increase or decrease may reflect changes in testing.

Figure 9 shows trend lines for number of diagnoses of the 5 main STIs among GBMSM in South West residents from 2017 to 2021. Gonorrhoea and chlamydia remained the most frequently diagnosed STIs among GBMSM from 2017 to 2021. Between 2017 and 2021, there was an overall decrease in STIs among GBMSM across the board. There was a peak exhibited in 2019 for number of gonorrhea, chlamydia and genital warts diagnoses. In 2021, gonorrhoea had the highest number of diagnoses (689) whilst genital herpes was the lowest (73).

Table 3. Percentage change in new STI diagnoses in GBMSM resident in the South West

Diagnoses	2021	Percentage change from 2017 to 2021	Percentage change from 2020 to 2021
New STIs	1,860	-29%	-10%
Syphilis	167	-21%	-24%
Gonorrhoea	689	-11%	-19%
Chlamydia	528	-28%	-1%
Genital herpes	73	-26%	40%
Genital warts	123	-51%	5%

Data sources: GUMCAD data only

See [note 4] above.

Table 3 shows the number of new STI diagnoses in 2021, as well as the percentage change from 2017 and 2020 to 2021, in GBMSM residents in the South West. In 2021, there were 1,860 new STI diagnoses made among GBMSM, a 29% decrease from 2017 and a 10% decrease from 2020. The number of diagnoses of all 5 STIs in GBMSM decreased in 2021 compared to 2017. The largest decrease was seen in genital warts (51% decrease) and the smallest change was in gonorrhoea (11% decrease). The number of diagnoses of syphilis, gonorrhoea and chlamydia also decreased between 2020 and 2021, whilst the number of genital herpes and genital warts increased between 2020 and 2021, despite decreasing compared to 2017. Between 2020 and 2021, the largest increase was seen in genital herpes (40% increase) and the largest decrease was in syphilis (24% decrease).

Figure 10a. Rate of new STI diagnoses per 100,000 population among South West residents by upper tier local authority of residence, 2021

Data sources: GUMCAD, CTAD

Figure 10a is a bar chart showing the rate of new STI diagnoses per 100,000 population among South West residents by UTLA of residence in 2021. The UTLA of the City of Bristol had the highest rate (616 (95% CI: 594 to 640) per 100,000), which was higher than the rate for England (538 per 100,000). All other UTLAs were below the rate for England. The other UTLAs with the highest rates were Bournemouth, Christchurch and Poole (521 (95% CI: 499 to 544) per 100,000), Swindon (495 (95% CI: 466 to 525) per 100,000) and Plymouth (473 (95% CI: 447 to 500) per 100,000). North Somerset had the lowest rate of new STI diagnoses in the South West (230 (95% CI: 210 to 251) per 100,000).

Figure 10b. Rate of new STI diagnoses (excluding chlamydia diagnoses in people aged 15 to 24 years) per 100,000 population aged 15 to 64 years among South West residents by upper tier local authority of residence, 2021

Data sources: GUMCAD, CTAD

Figure 10b is a bar chart showing the rate of new STI diagnoses (excluding chlamydia diagnoses in people aged 15 to 24 years) per 100,000 population of South West residents aged 15 to 64 years, in 2021, by UTLA. The City of Bristol remained as the highest rate (625 (95% CI: 599 to 653) per 100,000) and was the only UTLA where the rate was higher than the rate for England (604 per 100,000). Bournemouth, Christchurch and Poole, Swindon and Plymouth also remained in the same position, with rates of 578 (95% CI: 549 to 609) per 100,000, 573 (95% CI: 534 to 613) per 100,000 and 485 (95% CI: 453 to 520) per 100,000 population, respectively. North Somerset also remained as the UTLA with the lowest rate (263 (95% CI: 235 to 293) per 100,000).

Figure 11. Chlamydia detection rate per 100,000 population aged 15 to 24 years in South West residents by upper tier local authority of residence, 2021

Data sources: GUMCAD, CTAD

Figure 11 is a bar chart showing the chlamydia detection rate per 100,000 population aged 15 to 24 years in the South West by UTLA in 2021. The highest chlamydia detection rate in the South West was found in Torbay (1,475 (95% CI: 1,269 to 1,706) per 100,000). Other UTLAs with the highest chlamydia detection rates were Devon (1,394 (95% CI: 1,317 to 1,745) per 100,000), followed by Bournemouth, Christchurch and Poole (1,312 (95% CI: 1,212 to 1,418) per 100,000). Bath and North East Somerset had the lowest chlamydia detection rate (643 (95% CI: 562 to 734) per 100,000), followed by North Somerset (752 (95% CI: 638 to 881) per 100,000).

Figure 12. Rate of gonorrhoea diagnoses per 100,000 population in South West residents by upper tier local authority of residence, 2021

Data sources: GUMCAD

Figure 12 is a bar chart showing the rate of gonorrhoea diagnoses per 100,000 population in South West residents by UTLA in 2021. The highest rate of gonorrhoea was found in Bournemouth, Christchurch, and Poole (62 (95% CI: 55 to 71) per 100,000), followed by the City of Bristol (46 (95% CI: 40 to 53) per 100,000) and Swindon (40 (95% CI: 32 to 49) per 100,000). The lowest rate of gonorrhoea diagnoses was found in Dorset (14 (95% CI: 11 to 18) per 100,000) and North Somerset (14 (95% CI: 10 to 20) per 100,000).

Figure 13. Map of new STI rates per 100,000 residents by upper tier local authority in the South West, 2021

Data sources: GUMCAD, CTAD. Map contains Ordnance Survey data (© Crown copyright and database right 2021) and National Statistics data (© Crown copyright and database right 2021)

Figure 13 is a map of rates of all new STIs per 100,000 residents of the South West by UTLA in 2021. Only 2 UTLAs in the South West exhibited a rate of new STI diagnoses higher than 500 new diagnoses per 100,000 population: the City of Bristol (616.5 per 100,000) and Bournemouth, Christchurch, and Poole (521.4 per 100,000).

Figure 14. STI testing rate (excluding chlamydia in under 25 year olds) per 100,000 population in South West residents aged 15 to 64 years, 2017 to 2021

Data sources: GUMCAD, CTAD

Figure 14 shows trend lines for STI testing rates per 100,000 residents in the South West aged 15 to 64 years, from 2017 to 2021 (excluding chlamydia in people aged under 25 years). Between 2017 and 2021, the testing rate in the South West, has been consistently lower than the testing rate for England. A marginal increase in testing rates between 2017 and 2021 has been seen across both the South West and England, 2,331.9 to 2,388.3 and 3,246.0 to 3,422.4, respectively. Testing rates spiked in 2019 for both England and the South West and then decreased in 2020.

Figure 15. STI testing positivity rate [note 5] (excluding chlamydia in under 25 year olds) in South West residents, 2017 to 2021

Data sources: GUMCAD, CTAD

[note 5] The numerator for the STI testing positivity rate now only includes infections which are also included in the denominator. These are chlamydia (excluding diagnoses in those aged under 25 years), gonorrhoea, syphilis and HIV. Up to 2018 (data for 2017) it included all new STIs.

Figure 15 shows trend lines for STI testing positivity rates in South West residents from 2017 to 2021 (excluding chlamydia in those aged under 25 years). The STI testing positivity rate has been consistently lower in the South West compared to England, 3.7% in the South West for 2021 compared to 6.1% in England for the same year. Between 2017 and 2021, the STI testing positivity rate has decreased overall for both England and the South West.

Table 4. Number of diagnoses of new STIs by UKHSA region of residence, data source and data subset 2021

UKHSA region of residence	GUMCAD specialist SHSs	GUMCAD non-specialist SHSs [note 6]	CTAD [note 7]	Total
East Midlands	10,622	6,275	3,974	20,871
East of England	15,809	4,238	5,608	25,655
London	69,545	8,162	23,792	101,499
North East	7,495	1,580	2,718	11,793
North West	23,693	3,789	7,954	35,436
South East	26,578	1,960	8,287	36,825
South West	13,797	2,444	4,782	21,023
West Midlands	16,890	3,867	4,804	25,561
Yorkshire and Humber	16,031	2,050	7,724	25,805

Data sources: GUMCAD, CTAD

[note 6] Diagnoses from enhanced GPs reporting to GUMCAD are included in the ‘non-specialist SHSs’ total.

[note 7] Including site type 12 chlamydia from GUMCAD.

Table 4 shows the number of new STI diagnoses by UKHSA region of residence, data source and data subset (specialist or non-specialist SHS) in 2021. The highest total number of new STI diagnoses was in London (101,499) and the lowest was in the North East (11,793). In the South West, there were 16,241 diagnoses recorded in GUMCAD in 2021, 13,797 from specialist SHSs and 2,444 through non-specialist SHSs, and 4,782 diagnoses recorded in CTAD. Across all regions, higher numbers of diagnoses came from specialist SHSs.

Table 5. Number of diagnoses of the 5 main STIs in the South West by STI, data source and data subset 2021

5 main STIs	GUMCAD specialist SHSs	GUMCAD non-specialist SHSs [note 8]	CTAD [note 9]	Total
Syphilis	261			261
Gonorrhoea	1,130	458		1,588
Chlamydia	4,335	1,846	4,782	10,963
Genital herpes	1,957	7		1,964
Genital warts	2,710	62		2,772

Data sources: GUMCAD, CTAD

[note 8] Diagnoses from enhanced GPs reporting to GUMCAD are included in the ‘non-specialist SHSs’ total.

[note 9] Including site type 12 chlamydia from GUMCAD.

Table 5 shows the number of diagnoses of the 5 main STIs in the South West in 2021, by data source and data subset. The highest number of diagnoses of gonorrhoea, genital herpes, and genital warts in 2021 were made by at specialist SHSs. CTAD is a surveillance system only used for chlamydia, and in the South West, had a higher number of diagnoses than recorded by specialist SHSs in GUMCAD. Syphilis was diagnosed exclusively through specialist SHSs.

Information on data sources

Find more information on local sexual health data sources on GOV.UK.

These figures are based on data from the GUMCAD and CTAD surveillance systems published on 4 October 2022 (data to the end of calendar year 2021).

GUMCAD surveillance system

This disaggregate reporting system collects information about attendances and diagnoses at specialist (level 3) and non-specialist (level 2) SHSs. Information about the patient’s area of residence is collected along with demographic data and other variables. GUMCAD superseded the earlier KC60 system and can provide data from 2009 onwards. GUMCAD is the main source of data for this report.

Due to limits on how much personally identifiable information sexual health clinics are able to share, it is not possible to deduplicate between different clinics. There is a possibility that some patients may be counted more than once if they are diagnosed with the same infection (for infection specific analyses) or a new STI of any type (for new STI analyses) at different clinics during the same calendar year.

CTAD surveillance system

CTAD collects data on all NHS and local authority or NHS-commissioned chlamydia testing carried out in England. CTAD is comprised of all chlamydia (NAATs) tests for all ages (with the exception of conjunctival samples), from all venues and for all reasons. CTAD enables unified, comprehensive reporting of all chlamydia data, to effectively monitor the impact of the NCSP through estimation of the coverage of population screening, proportion of all tests that are positive and detection rates.

For services which report to GUMCAD and for which CTAD does not receive data on the patient’s area of residence (for example, SHSs), information about chlamydia diagnoses is sourced from GUMCAD data.

New STIs

New STI diagnoses comprise diagnoses of the following:

• chancroid
• Lymphogranuloma venereum (LGV)
• donovanosis
• chlamydia
• gonorrhoea
• genital herpes (first episode)
• HIV (acute and AIDS defining)
• Molluscum contagiosum
• non-specific genital infection (NSGI)
• non-specific pelvic inflammatory disease (PID) and epididymitis
• chlamydial PID and epididymitis (presented in chlamydia total)
• gonococcal PID and epididymitis (presented in gonorrhoea total)
• scabies
• pediculosis pubis
• syphilis (primary, secondary and early latent)
• trichomoniasis and genital warts (first episode)
• Mycoplasma genitalium
• shigella

Calculations

Confidence Intervals were calculated using Byar’s method.

Office for National Statistic (ONS) mid-year population estimates for 2020 were used as a denominator for rates for 2021. ONS ceased producing estimates of population by ethnicity in 2011. Estimates for that year were used as a denominator for rates for 2021.

Further information

As of 2020, all analyses for this report include data from non-specialist (level 2) SHSs and enhanced GP services as well as specialist (level 3) SHSs.

For further information, access the Sexual and Reproductive Health Profiles.

Find more information on local sexual health data sources on GOV.UK.

Local authorities have access to the Summary Profile of Local Authority Sexual Health (SPLASH) Reports (accessible from the Sexual and Reproductive Health Profiles) and the SPLASH supplement reports via the HIV and STI Data exchange.

For an Annual Epidemiological Spotlight on HIV in the South West, contact [email protected]

About the Field Service

The Field Service was established in 2018 as a national service comprising geographically dispersed multi-disciplinary teams integrating expertise in Field Epidemiology, Real-time Syndromic Surveillance, Public Health Microbiology and Food, Water and Environmental Microbiology to strengthen the surveillance, intelligence and response functions of UKHSA.

You can contact your local Field Service team at [email protected]

If you have any comments or feedback regarding this report or the Field Service, contact [email protected]

Acknowledgements

We would like to thank:

• local SHSs for supplying the SHS data
• local laboratories for supplying the CTAD data
• UKHSA Blood Safety, Hepatitis, STI and HIV Division for collection, analysis and distribution of data

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