Effects of COVID-19 vaccination and previous infection on Omicron SARS-CoV-2 infection and relation with serology

Abstract

An increasing proportion of the population has acquired immunity through COVID-19 vaccination and previous SARS-CoV-2 infection, i.e., hybrid immunity, possibly affecting the risk of new infection. We aim to estimate the protective effect of previous infections and vaccinations on SARS-CoV-2 Omicron infection, using data from 43,257 adult participants in a prospective community-based cohort study in the Netherlands, collected between 10 January 2022 and 1 September 2022. Our results show that, for participants with 2, 3 or 4 prior immunizing events (vaccination or previous infection), hybrid immunity is more protective against infection with SARS-CoV-2 Omicron than vaccine-induced immunity, up to at least 30 weeks after the last immunizing event. Differences in risk of infection are partly explained by differences in anti-Spike RBD (S) antibody concentration, which is associated with risk of infection in a dose-response manner. Among participants with hybrid immunity, with one previous pre-Omicron infection, we do not observe a relevant difference in risk of Omicron infection by sequence of vaccination(s) and infection. Additional immunizing events increase the protection against infection, but not above the level of the first weeks after the previous event.

COVID-19 vaccination-induced antibody responses and waning by age and comorbidity status in a large population-based prospective cohort study

“…COVID-19 vaccines show waning vaccine effectiveness over time, as was previously also observed in the VASCO study (10), and in line with the observed waning of S-antibodies in this study. We also reported lower vaccine effectiveness among participants with medical risk conditions, but it was not obvious that the difference in VE between those with and without medical risks changed over time (10). This is in line with our finding that S-antibodies of those with and without medical risk do not wane at a different pace.…”

“…We earlier showed a dose-response relationship between S-antibody GMC and protection against infection (10). COVID-19 vaccines show waning vaccine effectiveness over time, as was previously also observed in the VASCO study (10), and in line with the observed waning of S-antibodies in this study.…”

“…We earlier showed a dose-response relationship between S-antibody GMC and protection against infection (10). COVID-19 vaccines show waning vaccine effectiveness over time, as was previously also observed in the VASCO study (10), and in line with the observed waning of S-antibodies in this study. We also reported lower vaccine effectiveness among participants with medical risk conditions, but it was not obvious that the difference in VE between those with and without medical risks changed over time (10).…”

“…We showed earlier that hybrid immunity (i.e. a prior infection and vaccination) presents with higher protection against infection than only vaccination, but that waning of Santibodies was faster than waning of protection (10). Our data also show higher peak antibody levels among participants with infection prior to vaccination, however, we found mixed results concerning waning in this group of participants.…”

“…Assessing the antibody response in vulnerable groups is valuable since SARS-CoV-2 S-antibody concentrations may be an indicator for protection against infection (5,8,9). Indeed, the Dutch Vaccine Study COVID-19 (VASCO) population-based cohort showed a dose-response relationship between S-antibody concentrations and protection against infection (10). After the roll-out of COVID-19 vaccination campaigns in the Netherlands from January 2021 onwards, waning of vaccine effectiveness against severe disease and of antibody concentrations has been reported (1).…”