As discussed at the 2014 Conference on Retroviruses and Opportunistic
Infections (CROI), substantial advances have been achieved in using
laboratory tools to track the leading edge of HIV transmissions globally.
Phylogenetic and phylodynamic studies have identified clusters of new
infections occurring along geographic routes and in different groups,
including young men who have sex with men. New assays for detecting
acute HIV infection are promising; however, additional strategies are needed
to increase uptake of HIV testing in a number of populations. Globally,
people who inject drugs face numerous barriers to accessing HIV prevention
and treatment services and are in need of integrated approaches to deliver
services, address stigma and discrimination, and reform drug policies.
Young women and individuals in serodiscordant relationships continue to
be at high risk for HIV acquisition. Injectable hormonal contraception with
progestins may increase the risk of HIV infection. Bacterial vaginosis may
also increase HIV acquisition and transmission. Additional evidence suggests
antiretroviral therapy lowers HIV transmission in serodiscordant couples, but
high levels of diagnosis, linkage, retention, and viral suppression are needed
to reduce population-level HIV incidence. Several programs evaluating
the implementation of preexposure prophylaxis (PrEP) have shown high
uptake in the United States and resource-limited settings. As adherence is a
crucial determinant of PrEP efficacy, long-acting PrEP agents are promising
approaches being tested.