HIV Transmission Highest for Intermediate Viral Loads

Intermediate viral loads most common

THURSDAY, Oct. 25 (HealthDay News) -- HIV transmission is highest for infected individuals with intermediate asymptomatic viral loads, which are the most common, according to a report published online Oct. 22 in the Proceedings of the National Academy of Sciences.

Christophe Fraser, Ph.D., and colleagues from Imperial College London in the United Kingdom determined the set-point (asymptomatic) HIV-1 viral load in 123 Dutch homosexual men to assess its impact on the duration of asymptomatic infection. The investigators also used similar data from previously published studies in Zambian and Ugandan heterosexuals to determine the impact of set-point viral load on infectiousness.

The researchers found that higher set-point loads reduced the duration of asymptomatic infection. Individuals with common, intermediate viral loads had the highest transmission potential, while the transmission rate reached a plateau at high viral loads.

"To summarize, we have quantified the transmission potential of HIV-1 as a function of set-point viral load and have found that the most common set-point viral loads result in nearly optimal transmissibility over the lifetime of the host," Fraser and colleagues conclude.

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