People with moderate HIV viral loads are more likely to transmit the virus to a larger number of people over time than those with high viral loads, according to a study published Monday in the Proceedings of the National Academy of Sciences, Reuters reports. Lead researcher Christophe Fraser of Imperial College London and colleagues examined several groups of HIV-positive people in Africa, Europe and the U.S. They also analyzed previously published European and African studies that examined viral load, infectiousness and mortality.
The researchers focused on people with moderate viral loads because such individuals might not show symptoms or progress to AIDS for about seven to eight years, Reuters reports. Fraser said people with high viral loads typically progress to AIDS in a short period of time -- about two to three years. In addition, although individuals with high viral loads are the most infectious group, they have a limited amount of time to transmit the virus to others, according to the researchers. "The surprise was that those people with high viral loads actually infected fewer people because they progressed to AIDS more quickly," Fraser said.
People with moderate viral loads also form the largest, most common group not to receive treatment access, so these individuals likely play a larger role in contributing to the spread of HIV, the researchers said.
Fraser said the findings suggest that targeting people with the highest HIV viral loads might not be the most effective approach to fighting the spread of the virus. The findings also suggest that HIV has adjusted to reach the optimal balance between infectiousness and virulence to increase its chances of spreading, Fraser said. "We now want to see whether the virus has adapted in order to allow it to infect the most people, which seems plausible given the results of our study," Fraser said, adding, "While it is too early to sound the alarm, more research to prove or disprove this theory is urgently needed" (Kahn, Reuters, 10/22).
An abstract of the study is available online
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