Serologic surveillance of SARS-CoV-2 during the 2020 pandemic in exposed and unexposed healthcare workers in a tertiary care hospital in Amsterdam (S3 study)

Within our project, we followed up approximately 800 hospital workers during the COVID-19 pandemic through questionnaires and blood samples. We saw that employees who worked with COVID-19 patients were more likely to become infected with SARS-CoV-2 themselves. Genetic analysis of the virus showed that infection occurs more often from employee-to-employee than from patient-to-employee. In addition, our results show that there appears to be a certain cross-protection against SARS-CoV-2 thanks to previously acquired antibodies against another coronavirus that usually causes the common cold (OC43). Research into the immune response after vaccination shows that employees who have already been infected with SARS-CoV-2 showed a comparable or even better antibody response after 1 vaccination with BNT162b2 (Pfizer) compared to employees who have not previously been infected after 2 vaccinations. The results of this research are important in the areas of infection prevention, vaccine development and vaccination policy. Results: - Article about SARS-CoV-2 infections in different groups of hospital employees - Article about postponing the second mRNA vaccination in people previously infected with SARS-CoV-2 - Article about one-off mRA vaccination after previous infection with SARS-CoV-2 - Article about the effect of natural infection and vaccination against three variants of concern (VOCs)