WE KNEW things were bad, but in fact they are worse. For years, the US has been underestimating the rate of new HIV infections by a whopping 40 per cent.
Until now, most countries, including the US, estimated the number of new cases by applying correction factors to the latest data on national HIV prevalence.
The discrepancy came to light courtesy of in Atlanta, Georgia. By measuring the proportion of antibodies in an individual鈥檚 blood that are primed to fight HIV, it reveals when they were infected. A larger fraction indicates a more recent infection. When applied to US blood samples from 2006, the test indicates there were 56,300 infections that year, not 40,000 as assumed (The Journal of the American Medical Association, ).
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Are vast numbers of HIV infections being missed globally? It鈥檚 a tough one, says Kevin DeCock, director of HIV/AIDS at the World Health Organization. Estimates are based on the best figures available in what are often difficult settings, he says, but the US finding means 鈥渢here is a risk that we might sometimes underestimate鈥�.
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