Sexually transmitted infections in Scotland
2016 to 2025

About this release

This annual release by Public Health Scotland (PHS) provides data relating to several sexually transmitted infections in Scotland from January 2016 to December 2025. The report includes data on testing and laboratory confirmed diagnoses of chlamydia, gonorrhoea, and Mycoplasma genitalium infection extracted from the Electronic Communication of Surveillance in Scotland System (ECOSS) and the National Sexual Health (NaSH) system. Additionally, data on antimicrobial susceptibility testing and whole genome sequencing of Neisseria gonorrhoeae isolates in Scotland are presented.

Infectious syphilis (primary, secondary and early latent diagnoses) data are provided for the period from 2020 to 2025. The COVID-19 pandemic disrupted syphilis surveillance, leading to incomplete data from 2020 in the National Enhanced Surveillance of Infectious Syphilis in Scotland (NESISS) database. To address this, the number of diagnoses in each NHS Board for the years 2020 to 2025 were provided by sexual health services with data from NESISS providing demographic and behavioural information from enhanced surveillance forms submitted by sexual health clinicians for a subset of diagnoses.

Data for laboratory confirmed diagnoses of mpox are also presented and are based on enhanced surveillance forms submitted by health protection teams, linked to positive tests extracted from ECOSS.

More information on the sexually transmitted infections included in the report and the systems in which data are extracted for surveillance can be found in the glossary and appendix 1 on the main report.

Main points

Chlamydia

• In 2025, there were 10,785 diagnoses of chlamydia in Scotland, down from 11,730 in 2024.
• In 2025, women accounted for 55% of chlamydia diagnoses (5,916).
• In 2025, among women, 86% of diagnoses occurred in individuals aged under 30 years, compared with 64% among men
• There were 63 diagnoses of lymphogranuloma venereum (LGV) in 2025, a 10% decrease from 70 diagnoses in 2024.
• Testing for chlamydia through sexual health services decreased slightly between 2024 and 2025. The use of postal self-sampling kits for chlamydia testing also decreased. Testing levels were lowest among individuals aged under 20 years.
• The highest rate of chlamydia diagnoses from 2021 to 2025 was observed among heterosexual men in sexual health services.

Gonorrhoea

• In 2025, there were 4,509 gonorrhoea diagnoses in Scotland, down from 4,547 in 2024.
• Most diagnoses occurred in men (3,603) and were consistently higher than women across the ten-year period. From 2024 to 2025, diagnoses decreased among women but increased among men.
• Those aged under 25 years accounted for 59% of gonorrhoea diagnoses in women and 24% in men.
• Diagnoses of rectal gonorrhoea among men, a marker for condomless anal intercourse (CAI), increased to 1,559 in 2025 from 1,376 in 2024.
• The increase in gonorrhoea in 2022 and 2023 was mainly driven by diagnoses in those aged under 25 years, with 2024 and 2025 showing a more even rate of diagnoses across age groups.
• In 2024 and 2025, those aged under 20 years had the lowest testing numbers and highest rate of individuals testing positive compared to other age groups.
• The highest rates of individuals testing positive for gonorrhoea in the last five years were consistently observed among gay, bisexual, and other men who have sex with men (GBMSM).
• In 2025, three gonococcal isolates were resistant to ceftriaxone, stable from three in 2024. All three cases were treated successfully.

Infectious syphilis

• Infectious syphilis diagnoses decreased from a peak of 564 in 2023 to 522 in 2025.
• Across 2021-2025, where data was available:
  • 83% occurred among GBMSM
  • 94% were presumed to been acquired in Scotland
• In 2025, where stage of disease at diagnosis was available, 52% of cases were primary syphilis. The proportion of cases diagnosed as early latent had been decreasing since 2022, where the proportion of cases diagnosed as secondary syphilis has been increasing.

Mycoplasma genitalium

• In 2025, there were 211 diagnoses of genitalium, slightly lower than 221 in 2024.
• After an increase in testing from 2021 to 2024 there was a slight decrease in individuals tested from 1599 in 2024 to 1565 in 2025
• The highest number of tests from 2020 to 2025 was observed among heterosexual men, and the highest number of positives occurred among men (including heterosexual men and GBMSM).

Mpox

• In 2025, there were 16 diagnoses of mpox, compared to 14 in 2024, two in 2023, and 97 in 2022.
• Across 2022-2025, 76% of diagnoses were in individuals aged 30 years and over, 37% in those aged 30-39 years, and 93% among GBMSM.
• Across 2022-2025, Spain was the most frequently reported travel destination in the 21 days prior to symptom onset for mpox diagnoses.

Background

This report presents information on chlamydia, gonorrhoea, Mycoplasma genitalium, mpox, and infectious syphilis in Scotland to the end of December 2025. This report provides ten-year data trends and presents data observed during the COVID-19 pandemic which impacted significantly on the routes through which individuals had been able to access sexual health services. The impact of the COVID-19 pandemic is discussed further in the introduction of the main report.

Further information

The next release of this publication will be July 2027.