免疫学：SARS-CoV-2感染後の免疫は長期間持続する

Antibodies produced in response to SARS-CoV-2 infection continue to evolve over a 6-to-12-month period, and are boosted by vaccination, a Nature paper reveals. The findings suggest that immunity could be long-lasting in previously infected individuals, and that convalescent individuals who receive vaccines are likely to be protected against circulating SARS-CoV-2 variants.

Michel Nussenzweig and colleagues analysed blood samples from 63 people who had recovered from COVID-19 in the previous year. Of these, 26 had received at least one dose of either the Moderna or the Pfizer–BioNTech vaccines. From 6 to 12 months, the range of antibodies produced by memory B cells increased in range and potency, and when individuals were subsequently vaccinated, they went on to produce antibodies that were highly effective against SARS-CoV-2 variants, including variants of concern.

A year after infection, neutralizing activity against all forms of the virus included in this study was lower in people who had not been vaccinated than in those who had been vaccinated. This hints that vaccination increases immunity in those who have already had the disease. The authors also suggest that if B cells evolve in a similar manner in vaccinated people who have not had the disease, then an appropriately timed booster vaccine may be able to generate protective immunity against circulating variants.