8th Conference on Retroviruses and Opportunistic Infections Chicago, IL - February 4 - 8, 2001

Conf Retroviruses Opportunistic Infect 2001 Feb 4-8; 8:108 (abstract no. 225)

Harrison LH, do Lago RF, Moreira RI, Mendelsohn AB, Schechter M; Univ of Pittsburgh, PA.

BACKGROUND: There are limited data on effectiveness and behavioral impact of PEP to prevent HIV infection. PEP could increase the risk of HIV infection if its availability resulted in increased high- risk behavior.

METHODS: HIV-seronegative subjects from an HIV cohort among homosexual men with an annual HIV incidence of 3.1% were included. Participants were given a 4-day supply of ZDV + 3TC at enrollment and instructed to begin PEP immediately after sexual exposure of a mucous membrane to blood or semen and to report for evaluation within 96 hours. If the exposure was deemed to fulfill study criteria, a further 24-day supply was given. All participants were interviewed bi-annually concerning sexual exposures in the preceding 6 months.

RESULTS: As of September 30, 2000, 202 subjects had been followed for a mean (maximum) of 16 (21) months, respectively (total 3,218 person-months of follow-up, and a 12-month follow-up rate of 96%). The mean age was 28 years. At enrollment, the mean number of male partners in the previous 6 months was 9.7. The % of participants reporting any anal, oral or vaginal high-risk exposure at baseline and at 12 months were 56.2 and 45.4 (McNemar's test, p=0.01), 40.5 and 34.6 (p=0.17), 24.3 and 13.5 (p=0.003), and 4.8 and 5.9 (p=0.32), respectively. PEP was initiated 92 times by 65 participants; 83 (90.2%) of exposures were eligible. Although 74% reported at least one side effect, the full PEP course was completed 86% of the time. There were 8 HIV seroconversions, 7 of which were among non-PEP users. The annual seroincidence rates were 3.0% (95% CI: 1.3%, 5.9%), 3.9% (1.6%, 8.1%), and 1.1% (0.03%,6.4%) for the whole cohort, for those who never used PEP and for PEP users, respectively.

CONCLUSIONS: The reported behaviors on average improved in this cohort with access to PEP. Although there was a lower HIV seroincidence among PEP users, the limited statistical power of this preliminary analysis and the lack of a randomized controlled trial do not allow us to directly measure PEP efficacy. Future analyses will focus on whether break-through HIV infections are associated with antiretroviral-resistant HIV and on the effectiveness of PEP.

Keywords: AEGIS, Cohort Studies, Prospective Studies, HIV Infections, Zidovudine, Risk-Taking, Anti-HIV Agents, Lamivudine, Chemoprevention, Homosexuality, HIV Seropositivity, Reverse Transcriptase Inhibitors, Human, Male, Female, AIDS

2001-02-04
225

Copyright © 2001 - Foundation for Retrovirology and Human Health. Reproduction of this abstract (other than one copy for personal reference) must be cleared through the Foundation for Retrovirology and Human Health. Licensed (AIDSLINE) from National Library of Medicine.