Immunity to SARS-CoV-2 up to 15 months after infection

Summary Information concerning the longevity of immunity to SARS-CoV-2 following natural infection may have considerable implications for durability of immunity induced by vaccines. Here, we monitored the SARS-CoV-2 specific immune response in COVID-19 patients followed up to 15 months after symptoms onset. Following a peak at day 15–28 postinfection, the IgG antibody response and plasma neutralizing titers gradually decreased over time but stabilized after 6 months. Compared to G614, plasma neutralizing titers were more than 8-fold lower against variants Beta, Gamma, and Delta. SARS-CoV-2-specific memory B and T cells persisted in the majority of patients up to 15 months although a significant decrease in specific T cells, but not B cells, was observed between 6 and 15 months. Antiviral specific immunity, especially memory B cells in COVID-19 convalescent patients, is long-lasting, but some variants of concern may at least partially escape the neutralizing activity of plasma antibodies.
Graphical abstract
Highlights • Plasma neutralizing antibodies persist in the majority of patients up to 15 months • Neutralizing activity is lower against variants of concern Delta, Beta, and Gamma • Specific memory B and T cells were present in 95% of patients up to 15 months • Specific T cells, but not B cells, were decreased between 6 and 15 months
Immunology; Immune response; Virology