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SARS‐CoV‐2 re‐infection risk in Austria
Author(s) -
Pilz Stefan,
Chakeri Ali,
Ioannidis John PA,
Richter Lukas,
TheilerSchwetz Verena,
Trummer Christian,
Krause Robert,
Allerberger Franz
Publication year - 2021
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/eci.13520
Subject(s) - odds ratio , medicine , epidemiology , population , confidence interval , retrospective cohort study , coronavirus , disease , immunology , covid-19 , virology , infectious disease (medical specialty) , environmental health
Background A key question concerning coronavirus disease 2019 (COVID‐19) is how effective and long lasting immunity against this disease is in individuals who were previously infected with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). We aimed to evaluate the risk of SARS‐CoV‐2 re‐infections in the general population in Austria. Methods This is a retrospective observational study using national SARS‐CoV‐2 infection data from the Austrian epidemiological reporting system. As the primary outcome, we aim to compare the odds of SARS‐CoV‐2 re‐infections of COVID‐19 survivors of the first wave (February to April 30, 2020) versus the odds of first infections in the remainder general population by tracking polymerase chain reaction (PCR)‐confirmed infections of both groups during the second wave from September 1 to November 30, 2020. Re‐infection counts are tentative, since it cannot be excluded that the positive PCR in the first and/or second wave might have been a false positive. Results We recorded 40 tentative re‐infections in 14 840 COVID‐19 survivors of the first wave (0.27%) and 253 581 infections in 8 885 640 individuals of the remaining general population (2.85%) translating into an odds ratio (95% confidence interval) of 0.09 (0.07 to 0.13). Conclusions We observed a relatively low re‐infection rate of SARS‐CoV‐2 in Austria. Protection against SARS‐CoV‐2 after natural infection is comparable with the highest available estimates on vaccine efficacies. Further well‐designed research on this issue is urgently needed for improving evidence‐based decisions on public health measures and vaccination strategies.