Those who had Corona are similarly well protected as after vaccination

Spread the love

Read Time:2 Minute, 34 Second

Med-Uni Graz, in collaboration with Stanford University in California and AGES, has produced the first-ever study on the risk of re-infection with coronavirus. The result: one illness probably provides 91 percent protection against reinfection. The study is based on national infection data. The results were published in the “European Journal of Clinical Investigation,” Med-Uni Graz announced. However, the results should still be interpreted with caution.

More than 100 million people worldwide and more than 400,000 people in Austria have tested positive for SARS-CoV-2 so far. In prevention efforts, the question is how much a disease already suffered protects against reinfection. The answer may have considerable influence on vaccination strategies or model calculations of virus spread.

Low risk
A collaboration between the Medical University of Graz, Austria, AGES (Austrian Agency for Health and Food Safety) and Stanford University was the first to examine this question in a study using national infection data.

In the second wave of infection from September to November 2020, people who had contracted SARS-CoV-2 during the first wave of infection (February to April 2020) were compared with the rest of the Austrian general population. After an interval of approximately seven months from the initial infection, the following emerged: Individuals with a history of SARS-CoV-2 infection – compared with a first-time infection in the rest of the general population – had a 91 percent lower risk of reinfection

“Although we obviously have to be very careful with comparisons to vaccine studies, these results suggest that one has a similarly strong protection against reinfection after SARS-CoV-2 infection as after vaccination,” concluded Stefan Pilz of Med-Uni Graz. Pilz, along with Ali Chakeri of AGES, is the lead author of the technical publication.

Cautious interpretation
Reinfections with SARS-CoV-2 were detected in 40 people in the study, with the only death showing no causal link to reinfection. Although PCR testing was used to confirm the diagnosis, the study authors caution that the results should be interpreted with appropriate caution due to the tests not being 100 percent specific and various limitations in data reporting.

Nevertheless, the publication is likely to be of “crucial importance” because it is not only based on antibody determinations in special study populations, but for the first time presents the actual risk of reinfection in the entire population of a country, including all age groups.

Immunity in mutations questionable
“These data show an emerging immunity against SARS-CoV-2 in the Austrian population, although we currently do not know to what extent this immunity can also be applied to diverse SARS-CoV-2 viral mutations. Or how long and to what extent this reinfection protection lasts over longer periods of time,” emphasized Franz Allerberger of AGES.

Further evaluations of the reinfection risk over longer periods of time as well as data from other countries are therefore urgently needed. These will also be worked on in the future by the research group around Pilz, Franz and John P. A. Ioannidis from Stanford University.