Evaluation of COVID-19 vaccine effectiveness. Interim Guidance 17 March 2021

Download from WHO digital library	This publication has been updated with an addendum, 'Guidance on conducting vaccine effectiveness evaluations in the setting of new SARS-CoV-2 variants: Interim Guidance 22 July 2021', here: https://www.paho.org/en/documents/guidance-conducting-vaccine-effectiveness-evaluations-setting-new-sars-cov-2-variants