Anonymised HIV testing in gay men attending GUM clinics in England and Wales suggests that HIV transmission rates have not declined over the past five years, according to a study published today in the British Medical Journal.
Around 5% of men with acute sexually transmitted infections attending London GUM clinics in 1998 were HIV-positive and unaware that they were infected, and this level of undiagnosed HIV-infection has remained stable since 1993, according to Dr Michael Catchpole, Consultant Epidemiologist at the Public Health Laboratory Service Communicable Disease Surveillance Centre.
When men known to be HIV-positive were included, the proportion of acute STIs presenting in HIV-positive individuals was 9% in 1998 (a total of 123 individuals, of whom at least 64 had undiagnosed HIV infection). Although the proportion of individuals with acute STIs who are HIV-positive has declined since 1993, the researchers say that this change can be accounted for by changes in where HIV-positive individuals with an acute STI go for treatment after an HIV diagnosis.
Acute sexually transmitted infections such as gonorrhoea and undiagnosed urethritis increase levels of HIV in semen, even in individuals with viral load suppressed below the limits of detection in plasma, so the monitoring of HIV prevalence in this group of patients is essential.
Recent research has also highlighted the growing risk that newly infected individuals will have acquired drug-resistant virus. A survey of virus isolates from 69 UK seroconverters identified between 1994 and August 2000 found that 7 out of 8 individuals with drug-resistant virus were gay men, and that the risk of acquiring drug resistant virus had grown each year between 1994 and 1999 (Dean).
Another survey conducted by Royal Free Hospital and University College Medical School found that five of 34 recent seroconverters had at least one primary NRTI resistance mutation (14.7%), and evidence of horizontal transmission of drug resistance to each class of antiretrovirals was detected (Dann).
Reference
Catchpole M et al. Serosurveillance of prevalence of undiagnosed HIV-1 infection in homosexual men with acute sexually transmitted infection. British Medical Journal 321:1319-20, 2000.
Dann LC et al. Frequency of mutations associated with antiretroviral drug resistance in patients undergoing acute HIV-1 infection. Fifth International Congress on Drug Therapy in HIV Infection, Glasgow. AIDS 14 (supp4):S122, abstract P363, 2000.
Dean GL et al. Incidence of transmitted antiretroviral drug resistant HIV may be rising in the UK. Fifth International Congress on Drug Therapy in HIV Infection, Glasgow. AIDS 14 (supp4):S122, abstract P364, 2000.