Diagnoses of STIs continue to rise in Scotland

28 May 2019

Article: 53/2101

Two reports published by Health Protection Scotland (HPS) on 28 May 2019, reveal an increase in the number of sexually transmitted infections (STIs) diagnosed in Scotland between 2017 and 2018, specifically genital chlamydia, gonorrhoea and infectious syphilis.

Genital chlamydia remains the most frequently diagnosed STI in Scotland with 16,338 diagnoses reported in 2017, which represents a 4% increase compared to 2017. This STI predominates in women (58% of all diagnoses) and in young people (66% of all diagnoses were made in those aged less than 25 years), following on from similar patterns observed over the past decade.

In 2018, gonorrhoea diagnoses also increased with 3,233 diagnoses reported, indicating a 24% increase compared to the previous year and is the largest annual total recorded since the mid 1980s. In contrast to genital chlamydia, three quarters of gonorrhoea diagnoses were among men, 60% of whom were aged 25 and over. Since 2013, gonorrhoea diagnoses have increased by 103% (from 1,595 in 2013 to 3,233 in 2018).  The increase is largely due to a 121% increase in male diagnoses (from 1,056 to 2,339) and principally, among men who have sex with men (MSM). Female diagnoses increased by 66% (from 538 to 893) during the same period.  Rectal gonorrhoea, a marker of condomless anal intercourse (CAI), remained high in 2018.

Of particular concern in 2018, is the observed increase in the number of gonococcal isolates in Scotland demonstrating high-level resistance to azithromycin. This is outlined in a third report by the Scottish Bacterial Sexually Transmitted Infection Reference Laboratory (SBSTIRL) and HPS.

In addition to the increases noted in gonorrhoea and genital chlamydia infection, the number of diagnoses of infectious syphilis increased between 2017 and 2018 by 14% (from 399 to 455). This is the highest annual total recorded since the establishment of the surveillance system in 2002-2003 with the burden of infection among MSM (87% of diagnoses). The rise in infectious syphilis and gonorrhoea diagnoses mirrors the epidemiological picture in England in 2017, where increases of 20% and 12%, respectively, were reported.

Following the introduction of NHS-funded HIV pre-exposure prophylaxis (PrEP) in Scotland in July 2017, the impact of the PrEP programme on HIV and STI incidence is being monitored. During the first year of the programme, 1,872 individuals were prescribed PrEP, 99% of whom were MSM. While the impact of PrEP availability on HIV and STI incidence is not yet fully understood, it is possible that this intervention is associated with the observed increase in the incidence of STI diagnoses in MSM. Both HIV and STI incidence will continue to be monitored in the second year of the programme.

The findings of these reports highlight the continuing rates of unprotected sexual intercourse and the risk of STI infection, particularly among MSM, and underline the importance of a coordinated public health response to meet the challenges for the control and prevention of STIs in Scotland.