Severe Acute Respiratory Syndrome Coronavirus 2 Re-Infection Risk and Vaccine Efficacy in Austria

Study Overview
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Brief Summary
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The coronavirus disease 2019 (COVID-19) pandemic was caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. In this study, we aim to evaluate how strong and how long are individuals in Austria after vaccination and/or infection with 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 be stratified into different groups according to previous vaccinations against SARS-CoV-2 and previous SARS-CoV-2 infections. We primarily evaluate how strong and how long after vaccination against SARS-CoV-2 and/or infection with SARS-CoV-2, the risk for COVID-19 deaths is reduced or altered as compared to less vaccinated and/or infected persons. As secondary study aims, we perform such analyses 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 time periods of the COVID-19 pandemic, and we will also perform various subgroup analyses as for example according to age and gender. Given that antibodies against SARS-CoV-2 are usually detected after vaccination and/or infection, we will use such antibody data from blood donors in Tyrol, to elucidate how well the national health data on SARS-CoV-2 infections and vaccinations match with the respective antibody data, and how well these antibody data indicate risk of COVID-19 deaths and infections. We will calculate the probability of dying due to a SARS-CoV-2 infection (case/infection fatality rate) for different times of the COVID-19 pandemic, in order to document the health threat due to SARS-CoV-2. Based on all these data, we will calculate how many persons have to be vaccinated against SARS-CoV-2 to prevent one COVID-19 death at different times during this COVID-19 pandemic. We will consider the respective COVID-19 policies such as mask mandates, lock-downs, SARS-CoV-2 test mandates in our analyses and will 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-2 vaccinations and/or infections, and we will aim to collaborate with other research groups in order to extend our analyses. In conclusion, the results of this study should provide an overview on the COVID-19 pandemic with respect to protection conferred by vaccinations and previous SARS-CoV-2 infections, as well as the health threat of SARS-CoV-2, in order to provide knowledge for future COVID-19 policy and future pandemics.

Official Title
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SARS-CoV-2 Re-Infection Risk and Vaccine Efficacy in Austria: SARIVA Study

Conditions
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COVID-19

Intervention / Treatment
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* Biological: Vaccination against SARS-CoV-2


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Residency in Austria. Exclusion Criteria: - None.
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Vaccinated against SARS-CoV-2<br>Individuals who received a SARS-CoV-2 vaccine but have no record of a previous SARS-CoV-2 infection. Subgroups will be formed according to the number and type of vaccines against SARS-CoV-2. | Biological: Vaccination against SARS-CoV-2<br>* Interventions are either a vaccination against SARS-CoV-2 or an infection with SARS-CoV-2<br>* Other names: Infection with SARS-CoV-2;|
| Previously SARS-CoV-2 infected<br>Individuals who were previously infected with SARS-CoV-2 but have not received a SARS-CoV-2 vaccine. Subgroups will be formed according to the number and time period of previous SARS-CoV-2 infections. | |
| Hybrid Immunity against SARS-CoV-2<br>Individuals who received a SARS-CoV-2 vaccine and who were previously infected with SARS-CoV-2. Subgroups will be formed according to the number and time period of previous SARS-CoV-2 infections, the number and type of vaccines against SARS-CoV-2, and according to whether the vaccination or the infection was the first immune conferring event. | Biological: Vaccination against SARS-CoV-2<br>* Interventions are either a vaccination against SARS-CoV-2 or an infection with SARS-CoV-2<br>* Other names: Infection with SARS-CoV-2;|
| No immunity against SARS-CoV-2<br>Individuals who have not received a SARS-CoV-2 vaccine and were not previously infected with SARS-CoV-2. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| COVID-19 death | Death due to COVID-19 | January 1, 2000 to June 30, 2023 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| SARS-CoV-2 infection | Documented SARS-CoV-2 infection | January 1, 2000 to June 30, 2023 | 
| ICU stay | ICU stay of COVID-19 patients | January 1, 2000 to June 30, 2023 | 
| Hospitalization | Hospitalization of COVID-19 patients | January 1, 2000 to June 30, 2023 | 
| All-cause mortality | Death due to all-causes | January 1, 2000 to June 30, 2023 |