Demographic characteristics of the residents
Among the 1,243 eligible residents, 1,004 were analysed to assess the antibody response after the first jab. Seven hundred and thirty-five residents had always tested negative for SARS-CoV-2 RNA by RT-PCR, 94 had tested positive 9 to 12 months before the vaccine and 176 had tested positive 3 to 7 months before. Among those 1,004 residents, 808 accepted the second jab and agreed to participate in the study (Figure 1).