Neutralizing antibody responses over time in a demographically and clinically diverse cohort of individuals recovered from SARS-CoV-2 acquisition in Africa: A cohort study.

COVID-19 has affected millions worldwide. Research characterized immune responses of individuals who acquired SARS-CoV-2 and identified co-factors, such as HIV, associated with greater likelihood of poor clinical outcomes. SARS-CoV-2-specific neutralizing antibodies (nAbs) are a strong correlate of protection but their elicitation in people living with HIV (PLWH), and particularly in southern Africa, is less well characterized. HVTN 405/HPTN 1901 was an observational cohort study of individuals recently recovered from SARS-CoV-2. We describe 323 participants enrolled early in the pandemic (June 2020 to January 2021) in Zambia (n = 12), Malawi (n = 13), Zimbabwe (n = 59), and South Africa (n = 239), profiling their SARS-CoV-2-specific nAb responses and associations with demographics, comorbidities, disease severity, and time since diagnosis based on linear and logistic regression. Participants' median age was 39 years, 63.5% were assigned female sex at birth, 71.2% were black African, and 39 (12.1%) were PLWH. Approximately one in four participants (25.7%) had asymptomatic SARS-CoV-2, 47.4% were symptomatic but not hospitalized, and 26.9% were hospitalized with COVID-19. Participants in these groups were enrolled at a median of 51.5 days, 53 days, and 60 days post-SARS-CoV-2 diagnosis, respectively. SARS-CoV-2 nAbs were measured in serum using one of two calibrated assays. Most (291/322, 90.4%) participants had positive nAb responses at enrollment. Across all participants, nAb responses generally declined in magnitude between enrollment and 2-3 months thereafter, then increased through month 12 coincident with epidemiologically observed new waves of acquisition. In a multivariate model adjusted for potentially confounding factors, PLWH had a 65% lower geometric mean (GM) nAb ID50 titer compared to people without HIV (PWOH) (GMR: 0.35, p = 0.003, q = 0.006). Greater disease severity, older age (>55 years), high BMI (≥30) and diabetes were associated with higher nAb ID50 titers (all p < 0.05, all q < 0.20).These findings are important, as nAb titers are predictive of vulnerability to COVID-19.