Longitudinal humoral immunity against SARS-CoV-2 Spike following infection in individuals from Cameroon

This study followed how antibodies against the SARS‑CoV‑2 spike protein changed over time in people from Yaoundé, Cameroon who had confirmed COVID‑19 infection between March 2020 and January 2022. A total of 333 participants provided 626 blood samples up to roughly 6 months after diagnosis. The researchers measured levels of antibodies that bind to the virus’s spike protein and its receptor‑binding part, as well as how well the blood could neutralize live virus and trigger immune‑cell‑mediated killing of infected cells. They assessed responses to multiple virus versions, including Delta and Omicron subvariants.

Most people developed strong antibody responses after infection. Antibodies that could block the virus (neutralizing antibodies) declined faster over time than the overall number of antibodies that bind the spike or those that can help immune cells destroy infected cells (Fc‑effector functions). Older age and infection with different circulating virus variants were linked with differences in these responses. Even though neutralizing activity dropped, many individuals continued to have binding antibodies and functional responses for longer.

The results provide one of the first detailed pictures of how natural immunity to SARS‑CoV‑2 evolves over time in an African setting with limited vaccination during much of the pandemic. By showing that different aspects of the antibody response decay at different rates, this work helps explain how immunity might protect against reinfection or influence disease outcomes in populations like Cameroon’s.