Background:  We hypothesized that screening infants by rapid HIV-1 tests at 9 months can reduce the need for HIV-1 DNA polymerase chain reaction (PCR) testing and result in more mothers learning of their infant’s status.
Methods:  In a cohort study, HIV-1-infected women bringing infants for measles vaccination were offered infant HIV-1 testing. Dry blood spot samples were obtained for PCR testing and venous blood for rapid HIV-1 testing using the Abbot Determine and Bioline test kits simultaneously. Mothers were asked to return for PCR results in 1 month and were not informed of the rapid test results. Independent correlates of accepting infant testing and returning for test results were identified by multivariate logistic regression. The specificity, sensitivity, positive predictive value , and negative predictive value of the rapid HIV-1 assays compared to PCR were calculated.
Results: Of 294 women enrolled, 283 (96%) consented to infant testing, 168 (62%) returned to receive infant HIV-1 results and 30 (13%) infants tested positive by PCR. Women who knew their status antenatally, compared to those who did not, were more likely to accept infant testing (OR=3.7, 95%CI 0.94 ­ 14.39, p = 0.026) and to return for results (OR = 2.6, 95%CI: 1.4 – 4.5 p = 0.001). Women who were employed were less likely to return for infant results compared to those who were not (OR = 0.83, 95%CI 0.69 ­ 0.99 p = 0.041). The Abbott Determine^® and Bioline^® test kits had a specificity of 90% and 96%, sensitivity of 72% and 83%, negative predictive value of 0.96 and 0.98 and positive predictive value of 0.51 and 0.75, respectively. Using HIV rapid tests for screening and retesting infants who tested positive with at least one rapid assay by PCR would reduce the number of PCR tests done by 80% (225 of 283), not identify 16% (5 of 30) of infected infants and result in 10% (22 of 210) of uninfected infants being retested. However, waiting to receive PCR results would result in mothers not learning the status of 30% (9 of 30) of infected infants and 41% (85 of 210) of uninfected infants. Conclusions:  Contrary to expectation, rapid tests were more likely to give false negative than false positive results indicating a need to develop more sensitive rapid assays for infant testing. Many women fail to return for infant PCR test results and screening by rapid assays may result in more mothers receiving preliminary results.