Almost two thirds of South African men presenting with genital ulcer disease are already HIV-positive, and a further 12% of the HIV-negative men acquire HIV within the next month, according to a study presented at the International AIDS Conference in Mexico City on August 5th. The researchers concluded that men with genital ulcer disease should be targeted for HIV testing and prevention interventions.
Genital ulcer disease (GUD) refers to any kind of genital ulcers, possibly caused by a number of infections, including herpes, syphilis, chancroid and gonorrhoea. Numerous observational studies have shown that people with GUD and other sexually transmitted infections (STIs) are more likely to acquire HIV than people without GUD. A number of trials have looked into whether providing treatment for STIs leads to reductions in HIV acquisition, but the results have been disappointing.
However it is clear that HIV-positive people who also have genital ulcer disease have very high HIV viral loads, meaning that there is a much greater risk of HIV transmission during unprotected sex. Moreover, people who have recently acquired HIV also have high viral loads, so men who have both GUD and recent HIV infection pose a particular risk for HIV transmission.
The current study was led by Gabriela Paz-Bailey from the US Centers for Disease Prevention and Control, although the results were presented on her behalf by Sarah Hawkes.
A total of 615 men presenting at two South African primary clinics with symptoms of GUD were tested for HIV on presentation. A rapid antibody test was used, with positive results being confirmed with a different rapid test, and any discordant results were further investigated with a standard ELISA test.
Treatment for GUD was provided, and 28 days later all those who were HIV negative at baseline were re-tested for HIV. At this stage, stored blood samples from the baseline test were also re-tested using HIV nucleic acid amplification, which identifies those with very recent infection, before antibodies are produced.
HIV prevalence was already very high at baseline – 63% of men (387) had HIV antibodies. However just 21% of these men were aware of their HIV status.
Moreover, of the remaining 228 HIV negative men, 28 had in fact acquired HIV by the time of follow up at 28 days. Eight of these infections were identified with an antibody test, and 20 through the test for recent infection.
Therefore, among HIV-negative men at baseline, the incidence of new HIV infections within one month was 12.2% (28 of 228, 95% CI: 8.0 - 16.5). Looking at the overall study population, the incidence of HIV acquisition was 4.6% (28 of 615; 95% CI: 2.9 - 6.2).
In multivariate analysis, factors associated with recent HIV infection were having one or more casual partners in the past three months (OR 3.0), having HSV-2 (OR 1.4) and having ulcers of unknown cause (OR 5.0). It was noticeable that these were different risk factors to those for having HIV infection at baseline, where only HSV-2 and older age were significant.
Paz-Bailey noted that the rate of HIV acquisition is higher than in other clinic based settings, and that “GUD patients represent an opportunity to readily identify acute HIV infections and initiate care and prevention interventions that may reduce chances of HIV transmission, and provide clinical benefit to the patient.”