A group of much studied Nairobi sex workers who had remained HIV-negative despite frequent exposure to HIV have yielded another startling finding, according to British and US researchers. When the women reduced their number of sex partners, or took a break from commercial sex work, they appeared to be at greater risk of becoming HIV-positive.
The findings, presented on Tuesday at the Seventh Conference on Retroviruses in San Francisco, suggest that so-called immunity from HIV infection may be a consequence of a steady level of exposure to HIV, and that a reduction in exposure weakens the immune system’s ‘memory’ for HIV, leading to infection when HIV is subsequently encountered.
The researchers found that six women with evidence of immune reactivity to HIV, but no HIV antibodies, seroconverted between 1996 and 1999 after they reduced their number of sex partners or they took a break of several months from sex work, typically in order to visit their home villages outside Nairobi.
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Reference
Kaul R et al. Late seroconversion in HIV ‘resistant’ Nairobi prostitutes is associated with a preceding decrease in HIV exposure. Abstract 489, Seventh Conference on Retroviruses, San Francisco, 2000.