Probability of HIV Transmission During Acute Infection in Rakai, Uganda

Abstract

Accurate estimates of the probability of HIV transmission during various stages of infection are needed to inform epidemiological models. Very limited information is available about the probability of transmission during acute HIV infection. We conducted a secondary analysis of published data from the Rakai, Uganda seroconversion study. Mathematical and computer-based models were used to quantify the per-act and per-partnership transmission probabilities during acute and chronic HIV infection, and to estimate how many of the transmission events reported in the Rakai study were due to acute-phase HIV transmission. The average per-act transmission probability during acute infection equaled 0.03604 vs. 0.00084 for chronic HIV infection. Overall, HIV was transmitted during acute infection in 46.5% of 23 "incident index partner couples." Acute-phase transmission accounted for 89.1% of all transmission events in the first 20 months of follow-up. These results highlight the substantial risk of transmission during acute HIV infection.

Concurrent Sexual Partnerships and the HIV Epidemics in Africa: Evidence to Move Forward

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The HIV Seronegative Window Period: Diagnostic Challenges and Solutions

“…The initial stage, acute HIV infection, has a short duration (measured in weeks to months), is difficult to diagnose, and is associated with high levels of viremia (Dieffenbach and Fauci 2009). The large amount of virus in most newly infected individuals renders them highly infectious to others (Pinkerton 2008). Thus these primary and early infections should be the ones that early treatment is focused on.…”

Assessment of the Ability of a Fourth-Generation Immunoassay for Human Immunodeficiency Virus (HIV) Antibody and p24 Antigen To Detect both Acute and Recent HIV Infections in a High-Risk Setting

“…Such efforts have yielded significant returns in detection of recent HIV infection in certain communities (6,16,18,22,24). Evidence suggests that these individuals are at greatest risk for transmission of HIV and contribute disproportionately to the ongoing epidemic (17,19,20,25). However, the use of RNA-based detection methods is expensive, laborious, and can be operationally daunting.…”