Comparison of HIV oral fluid and plasma antibody results during early infection in a longitudinal Nigerian cohort

Background: Oral fluid (OF) testing is a less-invasive alternative to blood-based testing for HIV. The performance of HIV OF tests has not been extensively evaluated in serially collected paired specimens from seroconverters. Objective: To compare paired OF and plasma test performance in a cohort of HIV-1 seroconverters from Nigeria. Study design: Paired plasma and OF specimens from 14 seroconverters collected during 24 months of longitudinal follow up were included in the study. Plasma and OF were tested using Avioq HIV-1 Microelisa System, and first reactivity in plasma and OF specimens was compared. OF specimens reactive by Avioq were subsequently tested by OraSure HIV-1 Western blot. Genetic Systems HIV-1 Western blot was also performed on the corresponding plasma of the first 2 Avioq-OF positive time-points. Results: Of the 14 seroconverters, 5 (35.7%) had concordant results between plasma and OF for all time points tested, whereas 9(64.3%) showed reactivity on plasma before OF specimens early in infection. The median delay between plasma and OF reactivity was 29 days (range: 0 day-20 months) (p<0.0039); the median overall delay for OF compared to RNA testing was 69.5 days. Delayed antibody response with OF was observed in both males and females regardless of viral load or HIV subtypes. Conclusions: Results demonstrate decreased sensitivity of OF testing compared to blood-based testing with specimens obtained early after HIV infection. Programs that utilize OF testing in populations with increased risk of incident HIV infection should understand these limitations of OF testing. Published by Elsevier B.V.