ABSTRACT
There is limited data directly comparing the effectiveness of COVID-19 vaccines. We compared rates of SARS-CoV-2 Omicron BA.1/2 infection in Australian adults during March to May 2022 who had received one of four COVID-19 vaccines in the last 14-63 days as either a primary course or a booster dose. As a primary course, compared to recipients of BNT162b2 mRNA vaccine, adjusted hazard ratios for SARS-CoV-2 infection were 1.03 (95%CI 0.82-1.30), 1.19 (0.95-1.49), 1.70 (1.46-1.97) for respectively mRNA-1273, ChAdOx-1 nCov-19 and NVX-CoV2373. For booster dose, respective adjusted hazard ratios compared to BNT162b2 mRNA vaccine were 1.02 (95%CI 1.00-1.04), 1.20 (1.10-1.32), 1.39 (1.20-1.60). Our findings suggest relatively higher effectiveness of ancestral strain mRNA vaccines against SARS-CoV-2 Omicron infection than viral vector and protein subunit vaccines, but further studies are required due to small numbers of recipients of ChAdOx-1 nCov-19 and NVX-CoV2373.