Establishment and duration of protective immunity against SARS-CoV-2, in relation to severity of SARS-CoV-2 infection.

In most people, a specific immune response can be demonstrated after a COVID-19 infection. But it is not known how long and how well this immune response protects against reinfection. This can be investigated at Sanquin because blood is regularly taken from 300,000 blood donors, some of which is also stored for two years. Research The course of COVID-19 antibodies in the serum and (in a subgroup) the memory cells of donors who have had COVID-19 disease - from asymptomatic to seriously ill - will be analyzed for two years. The extent to which an immune response protects against re-infection is being prospectively investigated in 2000 antibody-positive donors. In addition, all people who test COVID19-PCR positive from September 2020 onwards will be checked whether they are blood donors. The plasma from these people that was frozen around July 2020 will then be tested. Expected outcomes If a previous infection is protective, it is expected that there will be much fewer anti-COVID-19 antibodies in the COVID-19 PCR positive group than in the control group.