By Mariana Bego
Long-term data have emerged regarding the durability of antibody responses in people who had COVID-19. In a recent Nature article, a team lead by Rockefeller University researcher Dr. Michel Nussenzweig reported immunity results from 63 people recovering from severe COVID-19 (convalescent individuals) up to 12 months post-infection. The authors suggest that immunity in convalescent individuals appears to be long-lasting and those who receive COVID-19 mRNA vaccines will mount an immune response that is protective against most circulating SARS-CoV-2 variants of concern.
– Individuals who have recovered from COVID-19 possess neutralizing antibodies and specific memory B cells A type of cell that is part of the adaptive immune system where their function is to memorize the antigen (protein) of a pathogen during an initial infection, so they can mount a stronger response if they encounter the pathogen again. that last for at least 12 months (and counting!).
– Vaccination in this group boosts this humoral immune response Is also referred to as antibody-mediated immunity and involves macromolecules found in fluids including antibodies produced by B cells and other blood proteins that are involved in fighting off pathogens. further.
– This boosted immune response appears to be broad and capable of neutralizing most circulating SARS-CoV-2 variants of concern.
The research team recorded stable levels of neutralizing antibodies recognizing the receptor binding domain (RBD) of the SARS-CoV-2 spike protein and RBD-specific memory B cells, from 6- to 12- months post-COVID-19 onset (with 12 months being the last time point collected prior to vaccination). This response was further boosted after vaccination; participants reached similar levels of neutralization activity against the original SARS-CoV-2 strain as against the circulating variants of concern tested, namely Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1) and Iota (B.1.526). Researchers observed that the cells producing these broadly neutralizing antibodies were predominant after vaccination.
The presence of these cross-reactive antibodies after vaccination, capable of neutralizing a broad variety of variants in individuals who recovered from COVID-19, hints that variant-tailored vaccines may not be necessary. If similar responses are observed in individuals without prior exposure to SARS-COV-2, the second dose of the current vaccines should lead to protective immunity against most circulating variants as well.
Wang Z, Muecksch F, Schaefer-Babajew D, Finkin S, Viant C, Gaebler C, Hoffmann HH, Barnes CO, Cipolla M, Ramos V, Oliveira TY, Cho A, Schmidt F, da Silva J, Bednarski E, Aguado L, Yee J, Daga M, Turroja M, Millard KG, Jankovic M, Gazumyan A, Zhao Z, Rice CM, Bieniasz PD, Caskey M, Hatziioannou T, Nussenzweig MC. Naturally enhanced neutralizing breadth to SARS-CoV-2 after one year. Nature 2021 Jun 14. doi: 10.1038/s41586-021-03696-9.