The basic immunizations (first and second vaccination) were performed from January to June 2021 using the m-RNA vaccine BNT162b2 (BioNTech/Pfizer, B)9 and the vector-based vaccine ChAdOx1-S (AstraZeneca, A). BNT162b2 was used to boost vaccine all study population. The time interval between the basic immunisation and the boost vaccination varied.~Four vaccine-groups could be distinguished:~Group 1 received BNT162b2 with the second vaccination 3 weeks after the first vaccination.~Vaccinees of groups 2 and 3 received AZD1222/ChAdOx1-S as first vaccination and could choose after 12 weeks whether second vaccination with BNT162b2 or AZD1222/ChAdOx1-S should be carried out. This results in homologous (first: AZD1222/ChAdOx1-S, second: AZD1222/ChAdOx1-S) and heterologous (first: AZD1222/ChAdOx1-S, second: BNT162b2) vaccine combinations.~Group 4 received BNT162b2 with the second vaccination 6 weeks after first vaccination.~Blood samples were collected at six time points: four weeks, three and six months after completion of the basic immunization, immediately before boost vaccination, four weeks and three months after boost vaccination.~Reactogenicity after first, second, and boost vaccination was assessed using questionnaires to determine vaccine-induced adverse drug reactions (ADR) within seven days after the respective vaccinations.~In addition, demographic data (age, gender, occupational group, allergies) were collected, local and systemic vaccination reactions are differentiated and the need for medication and inability to work as a result of vaccination reactions are prospectively recorded.
Investigation of the reactogenicity and immunogenicity of homologous and heterologous vaccine combinations with regard to the formation of SARS-CoV-2 antispike antibodies in health care workers after basic immunization and boost vaccination