HIV acquired during Dublin syphilis outbreak

As previously reported in our newsletter AIDS Treatment Update, an outbreak of syphilis is currently occurring in Dublin. Between March 2000 and October 2001, 182 cases of infectious syphilis were diagnosed in Dublin.

The overwhelming majority (92%) of cases occurred among gay or bisexual men. Of these, 23 were known to be HIV-positive.

In the last six months, 15 patients were co-diagnosed with early infectious syphilis and HIV. These patients had a documented negative HIV test in the previous 1 month to 3 years.

A case control study was undertaken by the researchers to identify the independent risk factors for HIV acquisition. The 15 men who had recently acquired HIV were compared to 100 controls who had early infectious syphilis but had also had at least one negative HIV test.

Demographics, risk behaviour (unprotected intercourse, sexual partners, drug and alcohol use) and other STIs were recorded.

The mean age, number of partners in the last three months and nationality were not statistically significantly different between cases and controls. No significant differences between venues and drug or alcohol use were observed between cases and control.

Innovative strategies to identify men with syphilis and raise awareness of the outbreak had been used throughout the outbreak. Onsite serological testing and the dissemination of sexual health information has been taking place in gay saunas, bars and clubs in Dublin.

Men who had recently acquired HIV and infectious syphilis were more likely to have unprotected sex with an HIV-positive partner. In total 10 of 15 were shown to have had an HIV-positive partner in the past year, yet only one was aware of his partner's HIV status.

In total, seven of the 15 men co-diagnosed with HIV also had gonorrhoea.

Onsite serological testing (in the bars, saunas and clubs) identified that 6% of the men (46 of 805 tested) had evidence of early infectious syphilis.

Syphilis is known to increase HIV viral load and increase the likelihood of both transmission and acquisition of HIV. In the mid 1990s only five or six gay men were diagnosed with HIV infection in Dublin. There is no sexual health strategy in Ireland.

Presenting the poster, Dr Hopkins told aidsmap "This is the first syphilis outbreak in Ireland since the 1970s, the first since the HAART era. The gay community were quick to take up syphilis awareness raising, our anxiety is that the constant rate of new syphilis infections will prompt an increase in our HIV incidence". She added "There has been three-fold rise in people presenting for regular sexual health screens and two dedicated syphilis clinics are seeing 50-60 gay men for syphilis testing each week.

There has not been any awareness raising activity for three months and recent figures show an increase in diagnoses over this time. Dr Hopkins advised people who test negative, but still have anxieties that they may have been exposed to either HIV or syphilis, to re-test after three months to be sure. The importance of regular sexual health screens to get treatment and avoid further transmission should be emphasized.