Vaccine Effectiveness Against Infection And Onwards Transmission Of Covid-19: Analysis Of Belgian Contact Tracing Data, January-June 2021

In Belgium, high-risk contacts of an infected person were offered PCR-testing irrespective of their vacci-nation status. We estimated vaccine effectiveness (VE) against infection and onwards transmission, con-trolling for previous infections, household-exposure and temporal trends. We included 301,741 tests from 25 January to 24 June 2021. Full-schedule vaccination was associated with significant protection against infection. In addition, mRNA-vaccines reduced onward transmission: VE-estimates increased to >90% when index and contact were fully vaccinated. The small number of viral-vector vaccines included limited interpretability. (C) 2021 The Author(s). Published by Elsevier Ltd.