Follow-Up of SARS-CoV-2 Antibody Levels in Belgian Nursing Home Residents and Staff Two, Four and Six Months after Primary Course BNT162b2 Vaccination oleh Eline Meyers, Liselore De Rop, Fien Engels, Claudia Gioveni, Anja Coen, Tine De Burghgraeve, Marina Digregorio, Pauline Van Ngoc, Nele De Clercq, Laëtitia Buret, Samuel Coenen, Ellen Deschepper, Elizaveta Padalko, Steven Callens, Els Duysburgh, An De Sutter, Beatrice Scholtes, Jan Y. Verbakel, Stefan Heytens, Piet Cools