SARS-CoV-2 infection shortly after BioNTech vaccination leads to high antibody levels

The Leibniz Research Centre for Working Environment and Human Factors in Dortmund (IfADo) studied residents and staff of a nursing home where a COVID-19 outbreak occurred shortly after the first BNT162b2 vaccination (BioNTech). The data show that people infected about ten days after their first vaccination have comparable antibody levels to fully vaccinated people.

For people without prior COVID-19 infection, vaccines provide some protection after the first dose. However, this protection does not occur until about 14 days after vaccination at the earliest. Therefore, infections are possible shortly after the first dose of a COVID-19 vaccine. This raises the question of what effect a SARS-CoV-2 infection shortly after the first dose of a vaccination has on antibody titres.

The IfADo therefore tested 82 residents and 94 staff of a nursing home who experienced a COVID‐19 outbreak shortly after their first vaccination with BNT162b2 in January 2021. The average age of the persons examined was 65 years. 53 people who received one dose of BNT162b2 and were then infected with SARS-CoV-2 10-18 days later had similar antibody levels as the group that received two vaccinations. This demonstrates that also a SARS-CoV-2 infection contributes to immunity and in this special setting it could replace a second vaccine dose.