Over 50% of gay men with recent HIV infection were not tested for HIV when attending a sexual health clinic, UK investigators report in the online edition of Sexually Transmitted Infections. The study also found that 80% of undiagnosed HIV-infected gay men with a sexually transmitted infection left the clinic without testing for the virus.
Furthermore, the investigators found several clusters of linked recent HIV infections.
They suggest that HIV testing policy in the UK needs to change, particularly the current recommendation that a test to confirm a negative result should be delayed for three months. The investigators believe that this recommendation is “detrimental”, noting that newer HIV testing technology can reduce the testing “window period” to one month.
The researchers also make a number of recommendations that they believe could help reduce the onward transmission of HIV from individuals with recent HIV infection.
A number of methods are available to healthcare workers and researchers to monitor the epidemiology of HIV amongst individuals testing for the virus at sexual health clinics.
Since 1989 anonymous HIV testing has been performed on left-over blood from syphilis tests performed at sexual health clinics. The samples cannot be traced to the source individual, but information is supplied about the patient’s HIV risk group, date of test, region of birth, diagnosis of other sexually transmitted infections, whether the patient was already known to be HIV-positive or if the patient was offered an HIV test.
It is also possible to use the STARHS assay (Serological Testing Algorithm for Recent HIV Seroconversion) to determine if HIV-positive individuals were recently infected with the virus.
Phylogenetic analysis can also be used to see if HIV infections are epidemiologically linked.
A UK team of investigators employed these three methods to assess the uptake of HIV testing amongst HIV-positive gay men and to see if individuals with very recent HIV infection were transmitting the infection to others before there had been an opportunity to diagnose their infection.
The investigators looked at anonymous samples collected from gay men between 1999 and 2002. Between these dates, a total of 28,530 samples were collected. Of these samples 3,592 were found to be HIV-positive and 1072 of these came from individuals whose HIV was previously undiagnosed. In addition, 229 (21%) of these samples derived from individuals with recent HIV infection.
Most of the men (86%) recently infected with HIV were resident in London, 56% were UK-born and 15% were born elsewhere in Europe.
A significantly higher proportion of HIV-negative men had an HIV test (56%) than did men with previously undiagnosed HIV (31%, p
Furthermore, only 42% of men with evidence of recent HIV infection were tested for the virus and an even lower proportion (28%) of men with chronic HIV infection were tested for the virus.
Only 22% of previously undiagnosed HIV-infected men with a sexually transmitted infection were tested for HIV compared to 45% of HIV-negative men with a sexually transmitted infection.
Phylogenetic analysis revealed the presence of seven clusters of linked recent HIV infections (16 individuals). Six of these were in London, the remaining cluster being in Wales. One cluster involved four individuals, the others pairs of infections.
Three clusters (six individuals) involved patients who were not tested for HIV and eight patients in the transmission clusters also had another sexually transmitted infection.
“More than half of recently HIV-infected MSM [men who have sex with men], and nearly 80% of all undiagnosed HIV-infected MSM with an STI [sexually transmitted infection], attending clinics…did not receive voluntary counselling and testing”, write the investigators.
They add, “diagnostic opportunity was missed among the recently HIV-infected and those with an STI.”
The investigators note that the study included samples obtained between 1999-2002, a period when HIV testing was low amongst gay men. More recent data suggest that levels of HIV testing have increased amongst this population. However, in 2006, 42% of gay men with undiagnosed HIV and a sexually transmitted infection were not tested for HIV when visiting a sexual health clinic and 63% of men with recent HIV infection left a sexual health clinic without being tested for HIV.
New UK HIV testing guidelines were recently published. The investigators believe that their findings have implications for UK HIV testing policy. In particular, they suggest that the reliability of fourth-generation HIV tests means that there is no need for individuals testing HIV-negative to be advised to wait three months after possible HIV exposure for a confirmatory test. Fourth generation tests, they note, can yield reliable results after a month.
They also suggest that testing alone may not be enough to prevent transmission of HIV from men with recent HIV infection. They recommend a number of additional strategies including “more rigorous partner notification; post-exposure prophylaxis among recently-exposed MSM; encouraging frequent, regular testing; educating MSM and health-care providers about seroconversion illness.”
Brown AE et al. Implications for HIV testing policy derived from combining data from voluntary confidential testing and viral sequences and serological analyses. Sex Transm Infect (online edition), 2009.