Prevalence and incidence of antibodies against SARS-CoV-2 among primary healthcare providers in Belgium during 1 year of the COVID-19 epidemic: prospective cohort study protocol, Adriaenssens, Niels, Scholtes Beatrice, Bruyndonckx Robin, Verbakel Jan Y., De Sutter An, Heytens Stefan, Van Den Bruel Ann, Desombere I, Van Damme Pierre, Goossens Herman, et al. , BMJ Open, Jul-01-2024, Volume 12, Issue 1, (2022)