Methods
396 residents from seven NHs suffering a SARS-CoV-2 B.1.1.7 (VOC-α)
outbreak at least 14 days after a vaccine campaign were repeatedly
tested using SARS-CoV-2 real-time reverse-transcriptase polymerase chain
reaction on nasopharyngeal swab test (RT-PCR). SARS-CoV-2
Receptor-Binding Domain (RBD) of the S1 subunit (RBD-IgG) was measured
in all residents. Nucleocapsid antigenemia (N-Ag) was measured in
RT-PCR-positive residents, and serum neutralizing antibodies in
vaccinated residents from one NH.