Vaccine effectiveness of primary and booster COVID-19 vaccinations against SARS-CoV-2 infection in the Netherlands from 12 July 2021 to 6 June 2022: a prospective cohort study

Authors:
Preprint
Publisher website
Google Scholar
Abstract
Introduction Monitoring of COVID-19 vaccine effectiveness (VE) is needed to inform vaccine policy. We estimated VE of primary vaccination, and first and second booster vaccination, against SARS-CoV-2 infection overall, and in four risk groups defined by age and medical risk condition, in the Delta and Omicron BA.1/BA.2 periods. Methods VASCO is an ongoing prospective cohort study among vaccinated and unvaccinated Dutch adults. The primary endpoint was a self-reported positive SARS-CoV-2 test during 12 July 2021-6 June 2022. Participants with a prior SARS-CoV-2 infection, based on a positive test or serology, were excluded. We used Cox proportional hazard models with vaccination status as time-varying exposure and adjustment for age, sex, educational level, and medical risk condition. We stratified by Delta and Omicron BA.1/BA.2 periods, risk group, and time since vaccination. Results 37,170 participants (mean age 57 years) were included. In the Delta period, VE Conclusions Our results show the benefit of booster vaccinations against infection, also in risk groups, although the additional protection wanes quite rapidly. Summary This prospective cohort study contributes to vaccine policy of COVID-19 by showing the benefit of booster vaccination in preventing SARS-CoV-2 infections, also in risk groups in which protection was generally lower, although the additional protection was rather short-lived.
All Related Versions

This publication has 22 references indexed in Scilit: