Rapid point-of-care CD4 testing at mobile units and linkage to HIV care: an evaluation of community-based mobile HIV testing services in South Africa.

BACKGROUND: Mobile HIV testing services (HTS) are effective at reaching undiagnosed people living with HIV. However, linkage to HIV care from mobile HTS is often poor, ranging from 10 to 60%. Point-of-care (POC) CD4 testing has shown to increase retention in health facilities, but little evidence exists about their use in mobile HTS. This study assessed the feasibility of POC CD4 test implementation and investigated linkage to HIV care among clients accepting a POC test at community-based mobile HTS. METHODS: This retrospective study used routinely collected data from clients who utilized community-based mobile HTS in the City of Cape Town Metropolitan district, South Africa between December 2014 and September 2016. A POC CD4 test was offered to all clients with an HIV positive diagnosis during this period, and a CD4 cell count was provided to clients accepting a POC CD4 test. Random effects logistic regression was used to assess factors associated with POC CD4 test uptake and self-reported linkage to care among clients accepting a POC test. Models were adjusted for sex, age, previous HIV test done, tuberculosis status and year of HIV diagnosis. RESULTS: One thousand three hundred twenty-five of Thirty-nine thousand seven hundred ninety clients utilizing mobile HTS tested HIV positive (3%). 51% (679/1325) accepted a POC test. The age group with the highest proportion accepting a POC test was 50+ years (60%). Females were less likely to accept a POC test than males (odds ratio = 0.7, 95%CI = 0.6-0.8). Median CD4 count was 429 cells/µl (interquartile range = 290-584). Among 679 clients who accepted a POC CD4 test, 491 (72%) linked to HIV care. CD4 cell count was not associated with linkage to care. CONCLUSION: Our findings suggest that mobile HTS can identify early HIV infection, and show that a high proportion of clients with a POC test result linked to care. Future research should assess factors associated with POC test acceptance and assess the impact of POC CD4 testing in comparison to alternative strategies to engage HIV positive people in care.

Impact of Home-Based HIV Testing Services on Progress Toward the UNAIDS 90-90-90 Targets in a Hyperendemic Area of South Africa.

BACKGROUND: In several subgroups of South Africa, the percentage of HIV-positive individuals aware of their status falls well below the UNAIDS 90% target. This study examined the impact that home-based HIV testing services (HBHTS) had on knowledge of status in a hyperendemic area of South Africa. METHODS: We analysed data from the second cross-sectional HIV Incidence Provincial Surveillance System survey (2015/2016), a representative sample (n = 10,236) of individuals aged 15-49 years. Participants completed a questionnaire, provided blood samples for laboratory testing (used to estimate HIV prevalence), and were offered HBHTS. The proportion of people living with HIV (n = 3870) made aware of their status through HBHTS was measured, and factors associated with HBHTS uptake were identified. RESULTS: Knowledge of HIV-positive status at the time of the survey was 62.9% among men and 73.4% among women. Through HBHTS, the percentage of HIV-positive men and women who knew their status rose to 74.2% and 80.5%, respectively. The largest impact was observed among youth (15-24 years). Knowledge of status increased from 36.6% to 59.3% and from 50.8% to 64.8% among young men and women, respectively. In addition, 51.4% of those who had previously never tested received their first test. Key reasons for declining HBHTS among undiagnosed HIV-positive individuals included fear and self-report of an HIV-negative status. CONCLUSIONS: HBHTS was effective in increasing awareness of HIV-positive status, particularly among youth, men, and those who had never tested. HBHTS could have a marked impact on progress toward the UNAIDS 90-90-90 targets within these subgroups.

Misdiagnosis of HIV infection during a South African community-based survey: implications for rapid HIV testing.

INTRODUCTION: We describe the overall accuracy and performance of a serial rapid HIV testing algorithm used in community-based HIV testing in the context of a population-based household survey conducted in two sub-districts of uMgungundlovu district, KwaZulu-Natal, South Africa, against reference fourth-generation HIV-1/2 antibody and p24 antigen combination immunoassays. We discuss implications of the findings on rapid HIV testing programmes. METHODS: Cross-sectional design: Following enrolment into the survey, questionnaires were administered to eligible and consenting participants in order to obtain demographic and HIV-related data. Peripheral blood samples were collected for HIV-related testing. Participants were offered community-based HIV testing in the home by trained field workers using a serial algorithm with two rapid diagnostic tests (RDTs) in series. In the laboratory, reference HIV testing was conducted using two fourth-generation immunoassays with all positives in the confirmatory test considered true positives. Accuracy, sensitivity, specificity, positive predictive value, negative predictive value and false-positive and false-negative rates were determined. RESULTS: Of 10,236 individuals enrolled in the survey, 3740 were tested in the home (median age 24 years (interquartile range 19-31 years), 42.1% males and HIV positivity on RDT algorithm 8.0%). From those tested, 3729 (99.7%) had a definitive RDT result as well as a laboratory immunoassay result. The overall accuracy of the RDT when compared to the fourth-generation immunoassays was 98.8% (95% confidence interval (CI) 98.5-99.2). The sensitivity, specificity, positive predictive value and negative predictive value were 91.1% (95% CI 87.5-93.7), 99.9% (95% CI 99.8-100), 99.3% (95% CI 97.4-99.8) and 99.1% (95% CI 98.8-99.4) respectively. The false-positive and false-negative rates were 0.06% (95% CI 0.01-0.24) and 8.9% (95% CI 6.3-12.53). Compared to true positives, false negatives were more likely to be recently infected on limited antigen avidity assay and to report antiretroviral therapy (ART) use. CONCLUSIONS: The overall accuracy of the RDT algorithm was high. However, there were few false positives, and the sensitivity was lower than expected with high false negatives, despite implementation of quality assurance measures. False negatives were associated with recent (early) infection and ART exposure. The RDT algorithm was able to correctly identify the majority of HIV infections in community-based HIV testing. Messaging on the potential for false positives and false negatives should be included in these programmes.

AUDIT, AUDIT-C, and AUDIT-3: drinking patterns and screening for harmful, hazardous and dependent drinking in Katutura, Namibia.

OBJECTIVES: To describe alcohol drinking patterns among participants in Katutura, Namibia, and to evaluate brief versions of the AUDIT against the full AUDIT to determine their effectiveness in detecting harmful drinking. METHODS: A cross-sectional survey was conducted in four constituencies and 639 participants, 18 years or older, completed a sociodemographic survey and the AUDIT. The effectiveness of the AUDIT-C (first three questions) and the AUDIT-3 (third question) was compared to the full AUDIT. RESULTS: Approximately 40% were identified as harmful, hazardous or likely dependent drinkers, with men having a higher likelihood than women (57.2% vs. 31.0%, p<.0001). Approximately 32% reported making and/or selling alcohol from home. The AUDIT-C performed best at a cutoff ≥ 3, better in men (sensitivity: 99.3%, specificity: 77.8%) than women (sensitivity: 91.7%, specificity: 77.4%). The AUDIT-3 performed poorly (maximum sensitivity: < 90%, maximum specificity: <51%). According to AUROC, the AUDIT-C performed better than the AUDIT-3. CONCLUSIONS: A large proportion of participants met criteria for alcohol misuse, indicating a need for screening and referral for further evaluation and intervention. The AUDIT-C was almost as effective as the full AUDIT and may be easier to implement in clinical settings as a routine screening tool in resource-limited settings because of its brevity.