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Recent HIV Infections Detected at a Mobile HIV Voluntary Counseling and Testing Program in Zimbabwe
Hong-Ha M. Truong*1,2, Hong-Ha M. Truong*1,2, K Fritz3, W McFarland1, W Hartogensis1, A Fiamma4, T Coates4, and S Morin1
1Univ of California, San Francisco, US; 2Gladstone Inst of Virology and Immunology, Univ of California, San Francisco, US; 3Johns Hopkins Univ, Baltimore, MD, US; and 4Univ of California, Los Angeles, US
Background: Mobile HIV
testing services in community settings have been shown to be acceptable in Sub-Saharan
Africa. We estimated HIV seroincidence at a mobile
HIV voluntary counseling and testing program in 2 Zimbabwean communities and
characterized risk factors associated with recent HIV infection.
Methods: Participants from the Zimbabwean communities
of Epworth and Seke (n = 1097) were screened for HIV-1 infection using a parallel rapid
testing algorithm comprised of 2 rapid tests (Unigold
and Determine). HIV antibody-positive specimens (n = 282) were characterized as recent HIV infections using the BED
immunoglobulin G capture enzyme immunoassay (BED-CEIA), applying an optical
density threshold of 0.8 and a 155-day seroconversion
window period. Annualized HIV seroincidence estimates
were calculated using a revised formula by McDougal et al, which adjusts for
misclassification of long-term and recent cases and for missing data. Associations
were assessed using the χ2 and Fisher’s exact statistical tests.
Results: The annualized HIV seroincidence
estimate was 1.91% (95%CI, 1.09 to 2.72), adjusted from an uncorrected estimate
of 6.89%. HIV seroincidence was slightly higher among
female testers than male testers (1.99% vs 1.88%, p = 0.626). Recent HIV infection did not
vary significantly by age (p = 0.243).
The highest proportion of recent infections detected were among persons ages 25
to 34 years old (10.5%) and were slightly higher among males than females in
this age group (11.9% vs 9.2%, p = 0.652). Persons recently infected compared with those with long-term
infections were more likely to report having had symptoms of an STD (33% vs 13%; OR 3.2; p
= 0.075) and having been treated for an STD (13% vs 6%;
OR 3.4; p = 0.187) in the last 6
months. No associations were found between HIV infection status and the perception
of being at risk for contracting HIV/AIDS (p
= 0.635) or the expectation of a negative or positive test result (p = 0.974).
Conclusions: Recent HIV infection detection among mobile voluntary
counseling and testing participants is a valuable measure for tracking the
spread of the epidemic among persons who might otherwise not have access to HIV
testing due to practical and logistical barriers. A higher proportion of recent
HIV infections were detected among men 25 to 34 years old. The adjusted HIV seroincidence estimate was more than 3-fold lower than the
uncorrected estimate, underscoring the importance of applying the adjustments
for seroincidence calculations.
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