A New AIDS Mystery:
Prostitutes Who Have Remained Immune
One of the mysteries of the AIDS epidemic is that a
small number of female prostitutes in Africa seem
resistant to the virus that causes the disease even
though they often have sex with infected men.
Despite an intensive search for immunologic
explanations, none have been found.
Now an even more baffling finding has turned up in a
study of 1,900 prostitutes in Nairobi, Kenya. Four of
them became infected with H.I.V., the virus that causes
AIDS, but only after they stopped working as prostitutes
or took breaks of two months or more, leaders of the
study reported at the Seventh Conference on Retroviruses
and Opportunistic Infections.Scientists cannot explain
this seeming paradox.
The prostitutes work in a Nairobi slum. In 1984,
researchers from the University of Nairobi and the
University of Manitoba in Winnipeg, Canada, began to
study and treat the women's sexually transmitted
diseases.
When the women enrolled in the study, two-thirds of
them were infected with H.I.V. The prostitutes said they
had five clients a day on average and used condoms with
about four of them. The researchers estimated that each
prostitute had unprotected sex with 60 to 70 infected
clients a year.
A small percentage of the prostitutes remained free of
infection for at least three years. No link has been
found between the women who became infected after
stopping commercial sex and their condom use or sex
practices.
Two possible explanations for the phenomenon : -
It could be, he said, that to maintain protection,
people need nearly continual exposure to H.I.V. so that
antigens in the virus can constantly boost the immune
system.
Or, perhaps sperm or semen somehow stimulate a
relatively short-lived immunologic reaction in the women
that protects them.
If either explanation is correct, an effective H.I.V.
vaccine may need to be given frequently.
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