Seroprevalence of SARS-CoV-2 after the Second Wave in South Africa in HIV-Infected and Uninfected Persons: A Cross-Sectional Household Survey, November 2020 – April 2021

Background: Seroprevalence studies are important for quantifying the burden of SARS-CoV-2 infections in resource-constrained countries. Methods: We conducted a cross-sectional household survey spanning the second pandemic wave (November 2020 – April 2021) in three communities. Blood was collected for SARS-CoV-2 antibody (two ELISA assays targeting spike and nucleocapsid) and HIV testing. An individual was considered seropositive if testing positive on ≥1 assay.  Factors associated with infection, and the age-standardised infection to case detection rate (ICR), infection hospitalisation rate (IHR) and infection fatality rate (IFR) were calculated. Findings: Overall 7959 participants were enrolled, with a median age of 34 years and HIV prevalence of 22.7%. SARS-CoV-2 seroprevalence was 45.2% (95% confidence interval 43.7% - 46.7%), and increased from 26.9% among individuals enrolled in December 2020 to 47.1% among individuals in April 2021. On multivariable analysis, seropositivity was associated with age, sex, race, being overweight/obese, having respiratory symptoms, and low socioeconomic status. Persons living with HIV (PLWH) with high viral load were less likely to be seropositive compared to HIV-uninfected individuals. The site-specific ICR, IHR and IFR ranged across sites from 4.4% to 8.2%, 1.2% to 2.5% and 0.3% to 0.6%, respectively. Interpretation: South Africa has experienced a large burden of SARS-CoV-2 infections, with <10% of infections diagnosed. Lower seroprevalence among non-virally suppressed PLWH, likely as a result of inadequate antibody production, highlights the need to prioritise this group for intervention. Funding Information: This study was supported by the South African MRC, Wellcome Trust and UK Foreign, Commonwealth and Development Office, and US CDC. Declaration of Interests: C. Cohen has received grant support from Sanofi Pasteur, Advanced Vaccine Initiative, and payment of travel costs from Parexel. NW and AvG have received grant support from Sanofi Pasteur. All other authors declare no conflict of interest. Ethics Approval Statement: This study was approved by the University of the Witwatersrand (M200861) and by the respective community and provincial research committees.