“We could do more to diagnose HIV in individuals identified as high risk who already access care”, write the authors of an editorial in the February edition of Sexually Transmitted Infections. They suggest modifications "to the recommendations to defer testing until 3 months after a possible exposure", noting that newer HIV testing technology can provide accurate results within a month of infection with HIV and that the current recommendations could deter testing during primary infection "when individuals are highly infectious."
The editorial accompanies a study showing that substantial numbers of gay men attending sexual health clinics in the UK were not tested for HIV. The study was reported on aidsmap.com here.
Large numbers of HIV-positive individuals in both the UK and US are unaware of their HIV infection. There is also good evidence that a substantial proportion of onward HIV transmissions originate from individuals who are unaware of their HIV infection. To reduce the number of undiagnosed infections, the US Centers for Disease Control and Prevention (CDC) issued guidance in 2006 recommending routine, opt-out HIV testing for adults using both primary and hospital based care. This is a shift away from the previous testing policy that targeted groups and individuals with a high risk of HIV. In late 2007, experts from across Europe met to discuss how to reduce undiagnosed infections.
However, the authors of the editorial believe that the results of the study conducted in UK sexual health clinics “suggest the failure of targeted testing may be partly due to missed opportunities for HIV testing in readily identified high risk populations”.
Targeted testing programmes should have two future objectives, recommend the authors:
- To increase the proportion of patients tested for HIV when they present for care.
- To increase the frequency of HIV testing for individuals such as gay men who are in a group with a high HIV risk.
They suggest that rapid HIV testing and opt-out testing could both help to achieve these aims, and the investigators note recent research showing that gay men in the UK were more likely to be tested for HIV if it was offered on an opt-out basis.
Concern is also expressed by the authors that “some individuals with a recent negative HIV test or risky exposure may be offered but defer testing because of concerns about the anti-body-negative ‘window-period’”. They note that newer HIV antibody tests can provide accurate results within one month and that this period can be shortened even further by nucleic acid amplification testing.
Individuals with recent HIV infection have very high viral loads and are especially infectious, with some research suggesting that up to 50% of all new infections originate in individuals who themselves have been recently infected.
The authors of the editorial therefore write: “the avoidance of testing during primary HIV infection…is likely to be counterproductive to the goals of reducing HIV transmission”.
At-risk populations, the authors recommend, should be encouraged to test more often and be educated about the symptoms of primary HIV infection. Some such campaigns have already been targeted at gay men in the US and are being considered in the UK. The US campaign presented gay men with information about the symptoms of primary infection, which can be mistaken for those of flu, and therefore recommended that gay men should avoid sex if they have flu-like symptoms.
Current HIV testing policy is passive, suggest the authors, with clinics waiting for at-risk individuals to present for care. They believe that modern information technology, such as email and text messaging “provide the potential for public health to play a more active role in increasing the frequency with which high-risk individuals seek testing”.
“HIV testing remains one of the sharpest tools in the HIV prevention toolbox”, write the authors. They conclude that this tool could be wielded most effectively by:
- Removal of barriers to testing, such as the need for written consent and counselling.
- More opt-out testing.
- Routine use of the most sensitive tests, including use of pooled nucleic acid amplification, for gay men and other high-risk groups.
- Increase frequency of testing for gay men and other high-risk groups.
Steklet JD et al. Learning from missed opportunities for HIV testing. Sex Transm Infect 85: 2-3, 2009.