Undiagnosed HIV infection results in delayed access to treatment and increased transmission. Self-tests for HIV may increase awareness of infection among men who have sex with men (MSM).

To evaluate the effect of providing HIV self-tests on frequency of testing, diagnoses of HIV infection, and sexual risk behaviors.

This 12-month longitudinal, 2-group randomized clinical trial recruited MSM through online banner advertisements from March through August 2015. Those recruited were at least 18 years of age, reported engaging in anal sex with men in the past year, never tested positive for HIV, and were US residents with mailing addresses. Participants completed quarterly online surveys. Telephone call notes and laboratory test results were included in the analysis, which was completed from August 2017 through December 2018.

All participants had access to online web-based HIV testing resources and telephone counseling on request. Participants were randomized in a 1:1 ratio to the control group or a self-testing (ST) group, which received 4 HIV self-tests after completing the baseline survey with the option to replenish self-tests after completing quarterly surveys. At study completion, all participants were offered 2 self-tests and 1 dried blood spot collection kit.

Primary outcomes were HIV testing frequency (tested ≥3 times during the trial) and number of newly identified HIV infections among participants in both groups and social network members who used the study HIV self-tests. Secondary outcomes included sex behaviors (eg, anal sex, serosorting).

Of 2665 participants, the mean (SD) age was 30 (9.6) years, 1540 (57.8%) were white, and 443 (16.6%) had never tested for HIV before enrollment. Retention rates at each time point were more than 54%, and 1991 (74.7%) participants initiated 1 or more follow-up surveys. More ST participants reported testing 3 or more times during the trial than control participants (777 of 1014 [76.6%] vs 215 of 977 [22.0%]; P < .01). The cumulative number of newly identified infections during the trial was twice as high in the ST participants as the control participants (25 of 1325 [1.9%] vs 11 of 1340 [0.8%]; P = .02), with the largest difference in HIV infections identified in the first 3 months (12 of 1325 [0.9%] vs 2 of 1340 [0.1%]; P < .01). The ST participants reported 34 newly identified infections among social network members who used the self-tests.