HIV-positive patients should be screened for syphilis every three months as part of their routine HIV care according to UK investigators writing in the journal Sexually Transmitted Infections.
Between 1996 and 2001, the number of cases of syphilis in the UK increased fourfold, largely due to outbreaks amongst gay men in several large cities. These outbreaks included a significant number of gay men who were HIV-positive.
It is recommended that HIV-positive patients are screened every six months for syphilis. However, clinicians at the Kobler Centre at London’s Chelsea and Westminster Hospital, the largest HIV treatment centre in the UK, reasoned that increasing syphilis screening to every three months could have additional benefits, by making a syphilis test part of routine HIV monitoring and by detecting and treating cases earlier, thereby reducing the possibility of onward transmission.
Routine testing for syphilis was increased from yearly to every three months at the Kobler Centre in May 2001. The investigators wished to see if this increased the number of patients tested for syphilis and if the screening programme was effective at detecting early cases of syphilis.
A total of 2,670 patients had a CD4 cell count performed at the Kobler between May 2001 and April 2002. Of these, 2,226 (85%) also had syphilis seriology performed. This represented a 27-fold increase in syphilis screening from the year before.
Twenty cases of asymptomatic syphilis were detected in gay men using VDRL seriology. The average time since last screening was six months. In addition, six cases of asymptomatic syphilis were detected using TPPA seriology, five being gay men and one a heterosexual man. These patients had last been screened for syphilis an average of four months previously.
Patients with syphilis who were treated with HAART were also much more likely than other HIV-positive patients to have a detectable HIV viral load (37% versus 17%).
In the twelve month period of the study, a total of 88 cases of early syphilis were diagnosed at the St Stephen’s Centre (which includes the John Hunter sexual health clinic as well as the Kobler Centre), with 52 of these cases in HIV-positive men. The 26 cases of asymptomatic syphilis detected by the enhanced screening programme at the Kobler Centre represented almost a third of all cases of syphilis seen at the two clinics and 50% of all cases seen amongst HIV-positive patients.
The investigators comment “in this screening programme we are diagnosing and treating a significant proportion of our early syphilis cohort earlier than presentation would be if symptomatic disease was allowed to develop, thereby reducing the infectious period of disease.”
Syphilis can, like some other sexually transmitted infections, increase the chance the chances of sexual transmission of HIV occurring. The investigators note that seven of the patients detected with early syphilis were failing HAART and had high viral loads.
“This syphilis screening programme may prevent syphilis transmission and transmission of drug resistant HIV variants” suggest the investigators, adding, “it is interesting to note that the virological success rate on antiretroviral therapy…is significantly lower [amongst patients with syphilis] than the current success rate in our unit.”
The investigators conclude by suggesting that three-monthly screening of HIV-positive patients for syphilis is appropriate.
Further information on this website
Syphilis - overview
Syphilis - factsheet
UK syphilis rise: majority of cases in gay men over half of whom are HIV-positive - news story
Winston A et al. Is increased surveillance for asymptomatic syphilis in an HIV outpatient department worthwhile?. Sexually Transmitted Infections 79: 257 – 259, 2003.