Generic protocol for ECDC studies of COVID-19 vaccine effectiveness against confirmed SARS-CoV-2 using healthcare worker cohorts : version 2.0

This document presents ECDC's generic protocol for a prospective multi-country cohort study to evaluate the effectiveness of the COVID-19 vaccine in hospital-based health workers, which was used to implement the study from March 2022. This document outlines standardised methods for establishing the study, collecting data and undertaking analysis as well as allowing for necessary local adaptions. The first version of this protocol (see version 1.0) was used up until March 2022, and also thereafter for those sites that obtained their ethical permit only after March 2022.