Assessment of Oral Fluid HIV Test Performance in an HIV Pre-Exposure Prophylaxis Trial in Bangkok, Thailand

Background

Rapid easy-to-use HIV tests offer opportunities to increase HIV testing among populations at risk of infection. We used the OraQuick Rapid HIV-1/2 antibody test (OraQuick) in the Bangkok Tenofovir Study, an HIV pre-exposure prophylaxis trial among people who inject drugs.

Methods

The Bangkok Tenofovir Study was a randomized, double-blind, placebo-controlled trial. We tested participants’ oral fluid for HIV using OraQuick monthly and blood using a nucleic-acid amplification test (NAAT) every 3 months. We used Kaplan-Meier methods to estimate the duration from a positive HIV NAAT until the mid-point between the last non-reactive and first reactive oral fluid test and proportional hazards to examine factors associated with the time until the test was reactive.

Results

We screened 3678 people for HIV using OraQuick. Among 447 with reactive results, 436 (97.5%) were confirmed HIV-infected, 10 (2.2%) HIV-uninfected, and one (0.2%) had indeterminate results. Two participants with non-reactive OraQuick results were, in fact, HIV-infected at screening yielding 99.5% sensitivity, 99.7% specificity, a 97.8% positive predictive value, and a 99.9% negative predictive value. Participants receiving tenofovir took longer to develop a reactive OraQuick (191.8 days) than participants receiving placebo (16.8 days) (p = 0.02) and participants infected with HIV CRF01_AE developed a reactive OraQuick earlier than participants infected with other subtypes (p = 0.04).

Discussion

The oral fluid HIV test performed well at screening, suggesting it can be used when rapid results and non-invasive tools are preferred. However, participants receiving tenofovir took longer to develop a reactive oral fluid test result than those receiving placebo. Thus, among people using pre-exposure prophylaxis, a blood-based HIV test may be an appropriate choice.

Below:  Kaplan-Meier estimates of time (28 day months) from date HIV was detected using nucleic acid amplification until the mid-point date between the last non-reactive and first reactive oral fluid HIV test. (A) By study drug group: tenofovir or placebo. (B) Controlling for study drug group, by HIV subtype: CRF01_AE or other subtypes.

Full article at:   http://goo.gl/Ic1ejt

By:   

Pravan Suntharasamai, Kachit Choopanya, Suphak Vanichseni, Udomsak Sangkum

Bangkok Tenofovir Study Group, Bangkok, Thailand

Michael Martin, Pairote Tararut, Wanna Leelawiwat, Philip A. Mock, Thitima Cherdtrakulkiat, Marcel E. Curlin

Thailand MOPH – U.S. CDC Collaboration, Nonthaburi, Thailand

Michael Martin, Roman J. Gvetadze, Janet M. McNicholl, Lynn A. Paxton, Marcel E. Curlin

Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America

Rapeepan Anekvorapong, Manoj Leethochawalit, Sithisat Chiamwongpaet

Bangkok Metropolitan Administration, Bangkok, Thailand

Somyot Kittimunkong

Thailand Ministry of Public Health, Nonthaburi, Thailand

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