The coronavirus disease 2019 (COVID-19) pandemic was caused by the severe acuterespiratory syndrome coronavirus 2 (SARS-CoV-2) virus. In this study, we aim to evaluatehow strong and how long are individuals in Austria after vaccination and/or infectionwith SARS-CoV-2 protected against COVID-19 disease.In this project, we will analyze national health data from all inhabitants of Austria(about 9 million persons) during the COVID-19 pandemic. The population of Austria will bestratified into different groups according to previous vaccinations against SARS-CoV-2and previous SARS-CoV-2 infections.We primarily evaluate how strong and how long after vaccination against SARS-CoV-2 and/orinfection with SARS-CoV-2, the risk for COVID-19 deaths is reduced or altered as comparedto less vaccinated and/or infected persons. As secondary study aims, we perform suchanalyses also for SARS-CoV-2 infections, hospitalizations and intensive care unit (ICU)stays, with or due to SARS-CoV-2. These analyses will be performed during different timeperiods of the COVID-19 pandemic, and we will also perform various subgroup analyses asfor example according to age and gender. Given that antibodies against SARS-CoV-2 areusually detected after vaccination and/or infection, we will use such antibody data fromblood donors in Tyrol, to elucidate how well the national health data on SARS-CoV-2infections and vaccinations match with the respective antibody data, and how well theseantibody data indicate risk of COVID-19 deaths and infections.We will calculate the probability of dying due to a SARS-CoV-2 infection (case/infectionfatality rate) for different times of the COVID-19 pandemic, in order to document thehealth threat due to SARS-CoV-2. Based on all these data, we will calculate how manypersons have to be vaccinated against SARS-CoV-2 to prevent one COVID-19 death atdifferent times during this COVID-19 pandemic. We will consider the respective COVID-19policies such as mask mandates, lock-downs, SARS-CoV-2 test mandates in our analyses andwill evaluate the impact of these policies on COVID-19 deaths and diseases. In addition,we will evaluate data on total mortality according to the number of SARS-CoV-2vaccinations and/or infections, and we will aim to collaborate with other research groupsin order to extend our analyses.In conclusion, the results of this study should provide an overview on the COVID-19pandemic with respect to protection conferred by vaccinations and previous SARS-CoV-2infections, as well as the health threat of SARS-CoV-2, in order to provide knowledge forfuture COVID-19 policy and future pandemics.