THE seemingly interminable AIDS winter is tightening its grip on southern
Africa, East Asia is feeling the chill and still there is no vaccine to halt the
devastating spread of HIV.
But compared with a year ago, scientists are much more confident. Progress is
being made. Key advances from studies on monkeys and humans鈥攕ome still
under wraps鈥攕uggest that some potential vaccines are much better than many
people were predicting this time last year.
One leading primate research centre in the US has found that a vaccine that
encourages the production of the immune system鈥檚 T cells makes HIV infection in
monkeys dramatically less severe. Given that the animals were exposed to
unnaturally large amounts of a highly virulent strain of the virus, there is
genuine hope that it could protect against infection during real-life sexual
encounters.
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Last year there was gloom when the prospects for one of the most talked-about
vaccine candidates, which was about to be tested in Kenya by Oxford University
immunologists, were dealt a severe blow. Some of the Kenyan prostitutes on whose
cells the vaccine was based because they were considered 鈥渋mmune鈥� to HIV, had in
fact become HIV-positive.
But the study went ahead and one researcher involved in it says initial
results suggest that the sceptics鈥攐f which she was one鈥攎ay be proved
wrong. 鈥淚 and a lot of other people feel much more optimistic than a year ago,鈥�
she said.
This vaccine, too, fights HIV by generating T cells rather than antibodies.
Most experts think a vaccine will have to generate both responses to be
completely effective. But pragmatists at the World Health Organization have
always said that partially effective vaccines are necessary steps on the way to
beating HIV.
And there is a growing feeling among vaccine researchers, strengthened by the
interest in AIDS vaccines now being shown by drugs giants such as Merck, that
good鈥攊f not 100 per cent effective鈥攙accines will be available by the
end of the decade. It won鈥檛 be a moment too soon.