Does promotion of PEP to gay men increase risk-taking?

Provision of post-exposure prophylaxis with antiretroviral drugs to gay men after a high risk sexual exposure to HIV (PEPSE) could inadvertently increase risk-taking in the absence of sound evidence that the intervention works to prevent HIV infection and change behaviour, argue doctors from two London hospitals in an editorial published in the June edition of Sexually Transmitted Infections.

They express disquiet over current United Kingdom and United States guidelines that recommend PEPSE in cases of high risk sexual exposure for gay men, and suggest that campaigns now being run to highlight the availability of PEP could have the paradoxical effect of increasing complacency about risk behaviours among the wider gay community, even if it has benefits for the small number of individuals who receive it.

“We believe there is a distinct danger that the promotion of PEPSE could reinforce rising trends in risky sexual behaviour, and might add to, rather than lessen, HIV transmission,” argues Dr John Richens of the Mortimer Market Centre, London.

“The most serious question that has to be asked about PEPSE is whether it could cause net harm, protecting only a few individuals at the expense of adverse effects on behaviour and increased HIV transmission in the wider community. Increases in unsafe sexual behaviour among homosexual men have been reported in many countries in the past few years. The coincidence of this phenomenon with improved therapy has attracted much speculation and debate. With this background it seems legitimate to ask whether promoting PEPSE could exacerbate these trends.”

They point to the growth in PEPSE at one London clinic, Mortimer Market, where prescriptions of PEPSE grew from 48 in 2003 to 119 in 2004. The projected drug cost for PEPSE alone at the clinic will be £180,000, they say, at a time when sexual health clinics are already financially stretched.

“We fear a backlash from unfavourable public opinion if large sums are to be spent without adequate evaluation. Media interest could also lead to large numbers of heterosexuals seeking PEPSE, a situation in which PEPSE will rarely be cost-effective in the United Kingdom.”

“Until the evidence is clearer, we should question the wisdom of a national campaign publicising access to free provision of PEPSE.”

The editorial is likely to prove controversial in the UK, where the Terrence Higgins Trust has been publicising the availability of PEPSE to gay men. PEPSE is currently justified for high-risk sexual exposures on the grounds that exposure through anal intercourse with ejaculation carries a considerably higher risk of infection than a needlestick injury, which would justify automatic post-exposure prophylaxis for a health care worker. It is also justified on the grounds of cost, say supporters, because whilst a month’s worth of antiretrovirals will cost less than £1,000, lifetime antiretroviral treatment for HIV could cost over £1 million.