SARS-CoV-2 Neutralizing Antibodies in Three African Countries Following Multiple Distinct Immune Challenges.

Background: The COVID-19 pandemic has affected Madagascar, Cameroon, and the Central African Republic (CAR), with each experiencing multiple waves by mid-2022. This study aimed to evaluate immunity against SARS-CoV-2 strains Wuhan (W) and BA.2 (BA.

Multiple SARS-CoV-2 immunizations of an unvaccinated population lead to complex immunity. A T cell reactivity study of blood donors in Antananarivo.

Background: Madagascar has undergone multiple and robust COVID-19 waves. The resulting immune background developed by its poorly vaccinated population has however not been described.

Methods: In this study, serological analysis and specific T cell response descriptions were used to describe the history of exposures of the capital's blood donors to SARS-CoV-2 and its VOCs.

Development and comparative evaluation of SARS-CoV-2 S-RBD and N based ELISA tests in various African endemic settings.

Management of the COVID-19 pandemic relies on molecular diagnostic methods supported by serological tools. Herein, we developed S-RBD- and N- based ELISA assays useful for infection rate surveillance as well as the follow-up of acquired protective immunity against SARS-CoV-2. ELISA assays were optimized using COVID-19 Tunisian patients' sera and prepandemic controls.

Linear epitope mapping of the humoral response against SARS-CoV-2 in two independent African cohorts.

Profiling of the antibody responses to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) proteins in African populations is scarce. Here, we performed a detailed IgM and IgG epitope mapping study against 487 peptides covering SARS-CoV-2 wild-type structural proteins. A panel of 41 pre-pandemic and 82 COVID-19 RT-PCR confirmed sera from Madagascar and Senegal were used.