Coordinated and sustained immune memory responses after mild COVID-19

Deciphering the persistence of memory responses to COVID-19 will aid in understanding long-term protection. A preprint by Rodda et al. provides a longitudinal analysis of humoral and cellular memory responses in 15 individuals who recovered from mild COVID-19. Sustained neutralizing IgG antibodies and memory B cells, expressing B cell receptors capable of neutralizing the virus when produced as antibodies, were detectable 3 months after symptom onset. Additionally, SARS-CoV-2-specific memory T cells persisted for more than 3 months. These proliferated and produced T helper 1 (T_H1) and T_H17 cell-associated cytokines upon antigen re-stimulation. Collectively, these data suggest that mild COVID-19 infection induces sustained memory responses that exhibit functional hallmarks associated with potent antiviral immunity. Further studies will be needed to fully dissect immunological memory responses, their durability and their contribution to long-term protection from SARS-CoV-2 re-infection.