Preliminary results from the population-based cohort study of the effectiveness of vaccine- and infection-induced immunization against SARS-CoV-2 variant omicron infection (includes all infections, regardless of clinical manifestation, regardless of severity of clinical manifestation) suggest high protective efficacy in the population group with combination of vaccine- and infection-induced immunization (referred to as hybrid immunity) and in the population group with triple vaccination. Among 12-17-, 18-59-, and 60-74-year-olds who had undergone more than 2 immunologic events (infection-induced +/- vaccine-induced immunization with >2 immunologic events, ie. infected multiple times, vaccinated + infected, or infected + vaccinated), there was a relative infection risk reduction compared with the immunnaive population group of 78.37% (95% CI: 76.86%-79.80%), 77.63% (95%CI: 76.89%-78.34%), and 88.94% (95% CI: 88.17%-89.67%), respectively. Similarly, among 5-11 year olds, protective efficacy against SARS-CoV-2 variant Omicron infection for this category of immunization was 76.30% (95%CI: 72.63% - 79.59%).

ALENA CHALUPKA, NORBERT HANDRA, LUKAS RICHTER, DANIELA SCHMID