Comparison of Adverse Effects of Two SARS-CoV-2 Vaccines Administered in Workers of the University of Padova.

Introduction : In Italy, on December 2020, workers in the education sector were identified as a priority population to be vaccinated against COVID-19. The first authorised vaccines were the Pfizer-BioNTech mRNA (BNT162b2) and the Oxford-AstraZeneca adenovirus vectored (ChAdOx1 nCoV-19) vaccines. Aim : To investigate the adverse effects of two SARS-CoV-2 vaccines in a real-life preventive setting at the University of Padova. Methods : Vaccination was offered to 10116 people. Vaccinated workers were asked to voluntarily report symptoms via online questionnaires sent to them 3 weeks after the first and the second shot. Results : 7482 subjects adhered to the vaccination campaign and 6681 subjects were vaccinated with ChAdOx1 nCoV-19 vaccine and 137 (fragile subjects) with the BNT162b2 vaccine. The response rate for both questionnaires was high (i.e., >75%). After the first shot, the ChAdOx1 nCoV-19 vaccine caused more fatigue ( p < 0.001), headache ( p < 0.001), myalgia ( p < 0.001), tingles ( p = 0.046), fever ( p < 0.001), chills ( p < 0.001), and insomnia ( p = 0.016) than the BNT162b2 vaccine. After the second dose of the BNT162b2 vaccine, more myalgia ( p = 0.033), tingles ( p = 0.022), and shivers ( p < 0.001) than the ChAdOx1 nCoV-19 vaccine were elicited. The side effects were nearly always transient. Severe adverse effects were rare and mostly reported after the first dose of the ChAdOx1 nCoV-19 vaccine. They were dyspnoea (2.3%), blurred vision (2.1%), urticaria (1.3%), and angioedema (0.4%). Conclusions : The adverse effects of both vaccines were transient and, overall, mild in severity.