San Francisco
A CONTROVERSIAL 鈥渕orning after鈥� treatment for people who fear that they have
been exposed to HIV through drug abuse or risky sex is to be tested by
researchers in San Francisco.
Some experts are concerned that such treatments will encourage reckless
behaviour. But others point out that worried people are already persuading
doctors to prescribe them drugs. Given this, they argue that a full trial is now
essential.
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Despite the popular name, the treatment involves a month-long course of the
AIDS drugs AZT and 3TC begun within 72 hours of a patient鈥檚 possible exposure to
HIV. The idea is to snuff out the virus before it has a chance to take hold. The
treatment is adapted from a study run by the Centers for Disease Control and
Prevention (CDC) in Atlanta, Georgia, on healthcare workers pricked while
handling syringes containing HIV-infected blood. In the CDC study, treatment
with AZT led to an 80 per cent reduction in the likelihood of becoming HIV
positive (This Week, 6 July 1996, p 7).
No one knows if the treatment will be similarly effective in drug abusers or
people exposed to HIV through sex. 鈥淭here are no data to say that it will work
in this very different setting,鈥� notes Dawn Smith, an epidemiologist with the
CDC.
Researchers at the University of California, San Francisco, and the San
Francisco Health Department want to assess the treatment鈥檚 value. In the first
instance, they aim to recruit about 500 patients for a year-long trial beginning
in January, and have already launched a small pilot study.
This first trial will assess what types of patients are attracted to the
programme, whether they stick to the demanding treatment schedule, and whether
counselling can encourage them to avoid the behaviours that put them at risk.
鈥淪o far, the patients we have seen have had one high-risk experience,鈥� says
Joshua Bamberger of the San Francisco Health Department. 鈥淭hey are desperate and
anxious and want help.鈥� Working out whether the treatment actually reduces the
chance of becoming HIV positive may require a subsequent, larger trial.
Some experts have grave reservations about the research, however. 鈥淵ou could
send the wrong message鈥攖hat it鈥檚 fine to practise risky behaviour because
this treatment is available afterwards,鈥� says Randall Pope, who directs the
Michigan Department of Community Health鈥檚 AIDS programme. There are also fears
that encouraging wider use of AIDS drugs could hasten the emergence of
drug-resistant strains of HIV.
Smith points out that the San Francisco trial is different from the CDC
needle-injury study in that the volunteers may not know whether their behaviour
has really put them at risk of contracting HIV, particularly in cases of casual
sex. This means that many people who have not been exposed to the virus could be
treated with drugs that can have nasty side effects.
But Bamberger and his colleagues argue that it is right to test the treatment
because desperate people are already using it. 鈥淎lready I鈥檝e had 20 or 30 health
departments ask me about it,鈥� agrees Smith. 鈥淚t鈥檚 happening across the country
and we have to at least start understanding if it works.鈥�