Second vaccination unnecessary for COVID-19 recovered patients

A new Vienna study with MedUni Wien Biobank involvement shows: A second dose of the Biontech and Pfizer vaccine against Covid-19 is not necessary for those who have recovered from COVID-19. The results were published by Viennese laboratory physicians in the “European Journal of Clinical Investigation”.

More than 660,000 people in Austria and more than 200 million worldwide have already been infected with SARS-CoV-2. This raised the question of how to proceed with the vaccination of Covid-19 recovered patients.


Perkmann and co-authors have demonstrated in their study on 69 people without a previous infection (seronegative) and 12 people who had recovered from Covid-19: All received a dose of the Covid-19 vaccine from Pfizer and Biontech. After 21 days they were examined for the concentration of antibodies in the blood. It turned out that the antibody concentration after the primary vaccination of convalescents differed more than a hundred times or more than 20 times that of those vaccinated for the first time without a previous Covid-19 episode, depending on the test method.


All 69 subjects without SARS-CoV-2 infection and with a primary vaccination and all 12 recovered study participants with a vaccination finally received the second dose of the mRNA vaccine. As a result, the antibody concentration in participants without SARS-CoV-2 disease increased by 25 times compared to the value after the initial vaccination. In those participants who had recovered from SARS-CoV-2 illness, the antibody concentration only increased by about half compared to the concentration after the first dose.


According to these study results, you can save yourself the double vaccination of SARS-CoV-2 convalescents. However, it would be important that international vaccination certificates, “green passports”, etc., clearly identify the existing vaccination protection for such persons, even with a partial vaccination.


Perkmann T., …, Mucher P., …, Haslacher H. Serum antibody response to BNT162b2 after natural SARS- CoV-2  infection. Eur J Clin Invest 2021 Aug 1;e13632. doi: 10.1111/eci.13632. Online ahead of print