Effectiveness of COVID-19 vaccines in preventing SARS-CoV-2 infection and hospitalisation, Navarre, Spain, January to April 2021

Abstract

COVID-19 vaccine effectiveness was evaluated in close contactsofcasesdiagnosedduringJanuary–April2021. Among 20,961 contacts, 7,240 SARS-CoV-2 infections were confirmed, with 5,467 being symptomatic and 559 leading to hospitalisations. Non-brand-specific one and two dose vaccine effectiveness were respectively, 35%(95%confidence interval (CI):25to44) and 66%(95%CI:57to74) against infections, 42%(95%CI:31to52)and82%(95%CI:74to88)against symptomatic infection, and 72%(95%CI:47to85) and 95%(95%CI:62to99) against COVID-19 hospitalisation. The second dose significantly increased effectiveness. Findings support continuing complete vaccination.