Research: Sexually transmitted infections: South West data

While this report primarily focuses on the trend between 2024 and 2025, some trends relative to 2019 or earlier are included to provide a comparison to sexual health service provision and sexually transmitted infection (STI) diagnoses prior to the 2020-2021 COVID-19 pandemic. Across England, the numbers of consultations, sexual health screens and STI diagnoses in 2020 and 2021 are lower than preceding years and any trends during periods which include those years must be interpreted in that context.

STIs represent an important public health problem in the South West. However, of all UK Health Security Agency (UKHSA) regions in England, the South West has the second lowest rate of new STIs.

A total of 22,470 new STIs were diagnosed among South West residents in 2025, representing an annual rate of 382 diagnoses per 100,000. Rates by upper tier local authority ranged from 281 new STI diagnoses per 100,000 in Somerset to 579 new STI diagnoses per 100,000 in Bournemouth, Christchurch and Poole.

The number of new STIs diagnosed in South West residents decreased by 11% between 2024 and 2025. Changes were seen in the numbers of the 5 main STIs: syphilis increased by 5%, gonorrhoea decreased by 26%, chlamydia decreased by 9%, genital herpes decreased by 3% and genital warts decreased by 6%.

UKHSA recommends that localities should be working towards achieving a chlamydia detection rate no lower than 3,250 per 100,000 among women aged 15 to 24 years and this is an indicator in the Public Health Outcomes Framework. In 2025, the chlamydia detection rate among South West women aged 15 to 24 years was 1,284 per 100,000 compared to 1,410 per 100,000 in 2024 and remaining well below the recommended level.