Thirty-seven percent of gay men diagnosed with syphilis in Manchester between 1999 and 2002 were HIV-positive, according to a study looking a factors involved in the recent return of syphilis to the city and published in the August 2003 edition of Sexually Transmitted Infections.
There has been a sixfold increase in the incidence of syphilis in the United Kingdom between 1996 and 2002. Local outbreaks of syphilis have largely accounted for this increase, with one of the earliest and largest being amongst gay men in Manchester. In response to this outbreak, public health officials initiated a system of “enhanced surveillance” in early 2000, collecting detailed epidemiological data to see if any themes in the transmission of the sexually transmitted infection could be established.
A total of 414 cases of syphilis were diagnosed in Manchester between 1999 and 2002, with 93% of cases being in men and 83% in gay men. The overwhelming majority of men, 90%, were white, and 82% were resident in the greater Manchester area.
A seasonal pattern to infections was established by the investigators, with the majority of syphilis cases reported in the summer or around the New Year festivities. Primary or secondary syphilis was diagnosed in 79% of instances, with the overwhelming majority of patients self-referring to sexual health services. Delayed diagnosis of syphilis was attributed to problems in obtaining appointments at sexual health clinics.
A sexually transmitted infection other than syphilis was detected in 30% of individuals and 37% of gay men with syphilis were also HIV-positive.
Unprotected oral sex was identified as the key transmission route, and although 61% of men said they knew oral sex without a condom was a high-risk activity for syphilis transmission, only 7% using condoms for oral sex. Investigators also established that 70% of men with syphilis were aware of outbreak of the disease prior to going to a sexual health clinic for syphilis testing and treatment. “These findings”, say the investigators, “suggest not only an increase in high risk sexual behaviour but also an increase despite widespread awareness of the risks."
Health education campaigns targeted at gay men successfully increased awareness about the risk of syphilis from unprotected oral sex. In 2000 only 37% of men considered unprotected oral sex to be a high-risk activity for syphilis, this increased to 65% by 2002. However, despite this increased awareness “transmission of syphilis has continued in Manchester and remained focused within the gay community.”
Long waiting times for appointments at sexual health services was identified as a possible factor contributing to missed syphilis diagnoses, and the investigators stress that urgent improvements to sexual health services in Manchester are needed if the syphilis is to be controlled.
The implications of the Manchester syphilis outbreak to the spread of HIV are also examined by the investigators. They note that 35% of gay men with syphilis were also HIV-positive and that the presence of an untreated sexually transmitted infection can increase the risk of contracting HIV by between two and fivefold. The investigators conclude “there is a very real risk of a significant increase in HIV among those infected with syphilis and this potential association should be made clear in intervention strategies. The rapid detection and treatment of syphilis may be a key factor in the successful attainment of the government’s target to reduce new cases of HIV by 25% by 2007.”
Further information on this website
Syphilis - overview
London syphilis outbreak 2001: over half of gay men HIV-positive - news story
HIV-positive patients should be tested for syphilis every three months says UK study - news story
UK syphilis rise: majority of cases in gay men, over half of whom are HIV-positive - news story
Ashton M et al. An outbreak no longer: factors contributing to the return of syphilis in Greater Manchester. Sexually Transmitted Infections 79: 291 – 293, 2003.