Frequent international travel by men who have sex with men recently diagnosed with HIV-1: potential for transmission of primary HIV-1 drug resistance.

We assessed the potential for international transmission of primary drug resistance among men who have sex with men newly diagnosed with human immunodeficiency virus (HIV) (n = 64) during the period in which they were unaware of their infection. During their exposure period, 55% of participants lived or traveled outside of the United States, and 59% had foreign-born sexual partners. Eighteen participants (28%) were classified as recently infected with HIV. Primary HIV-1 drug resistance was detected in eight participants (13%), four of whom were recently infected. Given the high frequency of international travel and prevalence of primary HIV-1 drug resistance among study participants, prevention strategies should incorporate specific counseling on risk of cross-border transmission.