Network Viral Load: A Critical Metric for HIV Elimination

BACKGROUND:Associations have been observed between an aggregate viral load measure, the community viral load, and new HIV diagnoses. The community viral load aggregates viral loads within chosen geographic areas, restricting inferences about HIV acquisition risk to these areas. We develop a more precise metric, the network viral load (NVL), to measure the composite viral load within a risk network of a HIV-negative individual. METHODS:We examined the relationship between NVL and HIV infection among young men who have sex with men in Chicago, United States. Networks were generated using respondent-driven sampling. NVL was defined as the prevalence of viremic individuals in oneʼs risk network, characterized as those with a viral load ≥20 k copies per milliliter. Permutation tests were conducted to account for dependency. RESULTS:After controlling for total connections, age, substance use during sex, syphilis diagnosis (previous 12 months), and frequency of condomless anal sex (previous 6 months), we found a positive association between NVL and HIV infection. Compared with a network with all HIV-seronegative members, the odds of HIV infection with an NVL of