In 2004, about 3 million people died of AIDS. Because sexual intercourse accounts for the vast majority of HIV transmissions worldwide, it is important to understand the events that occur in the genital or rectal mucosa during transmission. Here we dissect a number of factors in the transmitter and recipient that are relevant before, during, and after transmission. We weigh the evidence suggesting that the transmitted virus differs from the virus that predominates in the transmitter. We discuss the prospect for protection by innate and adaptive immune mechanisms at mucosal surfaces as well as by locally applied inhibitors of viral replication, microbicides. A better understanding of sexual transmission will enable more rational designs of vaccines and microbicides and potential combinations of the two.
PLoS Med (2006) 3 (2): e79. [doi:10.1371/journal.pmed.0030079]