IntroductionNational severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence data provides essential information about population exposure to the virus and helps predict the future course of the epidemic. Early cohort studies have suggested declines in levels of antibodies in individuals, associated with, for example, illness severity, age and co-morbidities. This protocol focuses on the seroprevalence among primary health care providers (PHCPs) in Belgium. They manage the vast majority of COVID-19 patients in addition to other patients and therefore play an essential role in the efficient organisation of health care. Currently, evidence is lacking on 1. how many PHCPs get infected with SARS-CoV-2 in Belgium, 2. the rate at which this happens, 3. their clinical spectrum, 4. their risk factors, 5. the effectiveness of the measures to prevent infection and 6. the accuracy of the serology-based point-of-care test in a primary care setting. Methods and analysisThis study will be set up as a prospective cohort study. General practitioners (GPs) and other PHCPs (working in a GP practice) will be recruited via professional networks and professional media outlets to register online to participate. Registered GPs and other PHCPs will be asked at each testing point (n=9) to perform a capillary blood sample antibody point-of-care test (OrientGene(R)) and complete an online questionnaire. The primary outcomes are the prevalence and incidence of antibodies against SARS-CoV-2 in PHCPs during a 12-month follow-up period. Secondary outcomes include the longevity of antibodies against SARS-CoV-2. Ethics and disseminationEthical approval has been granted by the Ethics Committee of the University Hospital Antwerp/University of Antwerp (Belgian registration number 3002020000237). Alongside journal publications, dissemination activities include the publication of monthly reports to be shared with the participants and the general population through the publicly available website of the Belgian health authorities (Sciensano). RegistrationTrial registration number NCT04779424 Article summaryO_ST_ABSStrengths and limitations of this studyC_ST_ABSO_LIThis large cohort study will provide regular, timely and precise data at national level on prevalence and incidence of antibodies against SARS-CoV-2 among primary health care providers (PHCPs) managing the vast majority of COVID-19 and other patients and therefore essential to organise health care efficiently. C_LIO_LIThis study will familiarise PHCPs with the use of serology-based point-of-care tests (POCTs) and validate the POCT in a primary care setting. C_LIO_LIMissing data points and the use of a convenience sample could limit the validity of the study results. C_LI