UK and US syphilis cases still on the rise

Alarming statistics released yesterday from both the UK and US reveal that the syphilis epidemic continues to grow unabated on both sides of the Atlantic, particularly amongst gay men with HIV infection.

In the past year, according to the UK's Public Health Laboratory Service (PHLS), new diagnoses of syphilis have more than doubled amongst the population as a whole (715 vs. 333), with new diagnoses amongst gay men almost trebling (126 vs. 350) in the same period.

Of 492 new syphilis diagnoses reported in London between April 2001 - June 2002, 74% were in gay men, half of them coinfected with HIV.

The US Centers For Disease Control and Prevention (CDC) have reported their first rise in new syphilis cases since 1990. The 2.1% rise was only reported in men, and although the CDC does not collect information on sexual orientation, outbreaks of syphilis have been reported amongst gay men in several urban centres. The latest report from San Francisco's Department of Public Health (September 2002), where 302 new syphilis infections were diagnosed amongst gay men in the first nine months of this year, found that 69% were HIV positive.

Both the UK and US reports highlight the connection between HIV, syphilis and high risk sexual behaviour amongst gay men. Those who were coinfected with HIV and syphilis tended to make higher use of 'sexual market places' like bars, saunas, internet and cruising grounds, and had more sexual partners than men infected with syphilis who were not HIV-positive.

Since syphilis can be transmitted through both oral and anal sex, unprotected anal intercourse reported amongst gay men is unlikely to be the sole reason for the current syphilis epidemic.

In the UK, although new cases of syphilis are rising fastest amongst gay men, there are regional, age and gender differences. Although the original syphilis outbreaks amongst gay men were reported in London, Manchester (North West) and Brighton (South East), London and the North West (7.7 and 5.2 per 100,000, respectively) saw the highest rates of new diagnoses in 2002 (7.7 and 5.2 per 100,000, respectively) , whilst the West Midlands and Northern Ireland (reporting in 2001 for the first time) are now experiencing higher rates of new syphilis infection than the South East.

The West Midlands is also experiencing the second highest rate of new diagnoses in women after London (0.5 and 1.4 per 100,000, respectively), followed by the North West, Northern Ireland and Yorkshire. Notably, Eastern and South East regions of the UK both saw significant decreases amongst new diagnoses amongst women.

Syphilis is most common amongst the 25-34 age group followed by 35-44 year-olds. However, 20-24 year-olds experienced the greatest increase in new diagnoses in 2001.