AIDS vaccine may offer hope only for some ethnic groups
Lynn Eaton, London
An AIDS vaccine, which has been in phase III trials for the past three years,
has failed to show a significant reduction inthe development of HIV
among the those who were vaccinated, themanufacturer, VaxGen, hasannounced.
But the vaccine has shown a significant reduction in certain ethnic groups,
indicating that black and Asian volunteers mayhave produced higher
levels of antibodies against HIV than whiteand Hispanic
volunteers.
The full trial results are to be presented later this month at a symposium on
HIV and will then be analysed by the US Foodand Drug
Administration.
In all, more than 5000 people took part in the randomised, double blind,
placebo controlled trial, which took place in theUnited States,
Canada, Puerto Rico, and the Netherlands. Volunteersincluded
5108 gay men and 309 at risk women. All were HIV negativewhen they
joined the trial. In all, they received seven injectionsover the
three yearperiod.
The initial results are based on volunteers who received the primary course
of three injections (of the vaccine or placebo)over the first six
months; 3330 volunteers received the AIDSVAXB/B injection and
1679 receivedplacebo.
At the end of the three year period, the percentage of volunteers developing
HIV was 5.7% in the vaccine group and 5.8% inthe placebo
group.
Among ethnic minorities excluding Hispanic volunteers, however, there were
67% fewer HIV infections in those receiving thevaccine than in those
receiving placebo (P value <0.01; n=498).And among black volunteers
this reduction rose to 78% (P<0.02,n=314).
The size of these two groups, however, is small. The vast majority of
volunteers were white (4185); 326 were Hispanic and498 non-white
(black, Asian, and other); only 314 were black.In the non-white
group, 17 of the 171 (9.9%) volunteers givenplacebo became infected,
compared with 12 of the 327 (3.7%) giventhe vaccine. Among the black
volunteers, 9 of the 111 (8.1%) givenplacebo became infected,
compared with only 4 of the 203 (2%)givenvaccine.
The vaccine is made up of a recombinant form of the protein (gp120) found on
the surface of HIV. These genetically engineeredproteins mimic the
two strains of HIV subtype B antigens thatare prevalent in the
strain of the virus found in North America,Europe, Australia, Japan,
and Puerto Rico.
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-- Albert Einstein, letter to a friend, 1901
"I know of no safe depository of the ultimate powers of the society but the people themselves, and if we think them not enlightened enough to exercise control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education."
-- Thomas Jefferson, letter to William C. Jarvis, September 28, 1820
"What's the point of vaccination if it doesn't protect you from the unvaccinated?"
-- Sandy Gottstein
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