[154]BEHAVIORAL IMPACT OF THE AVAILABILITY OF POST-SEXUAL-EXPOSURE CHEMOPROPHYLAXIS (PEP) FOR HIV: A PROSPECTIVE COHORT STUDY

1st International AIDS Society Conference on HIV Pathogenesis and Treatment

Buenos Aires, Argentina - July 8-11, 2001

[TITLE:] BEHAVIORAL IMPACT OF THE AVAILABILITY OF POST-SEXUAL-EXPOSURE CHEMOPROPHYLAXIS (PEP) FOR HIV: A PROSPECTIVE COHORT STUDY

[AUTHOR(S):] Schechter M, Lago R, Moreira R, Mendelsohn A, Harrison L
Hospital Universitario Clementino Fraga Filho Rio De Janeiro, Rio De Janeiro, Brasil

IAS Conf HIV Pathog Treat 2001 Jul 8-11;1st: Abstract No. 154

[ABSTRACT:] 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 homosexual males were included. Participants were given a 4-day supply of ZDV+3TC and instructed to begin PEP immediately after sexual exposure of a mucous membrane to blood or semen, and to report for evaluation within 4 days. For exposures deemed to fulfill study criteria, a further 24 day supply was given.

Results: As of 01.31.2001, 202 subjects had been followed for a median (maximum) of 18 (22) months (total 3,503 person-months of follow-up); the 18 month follow-up rate was 96%). The median 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 18 months were 56.6 and 45.0 (McNemars test, p=0.005), 40.4 and 29.0 (p=0.007), 24.8 and 15.0 (p=0.002), and 4.6 and 7.5 (p=0.06), 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 2.7% (95% CI: 1.2%, 5.4%), 5.7% (2.3%,11.7%), and 1.0% (0.03%,5.6%) 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.

010711
154