Many critical questions remain about the effectiveness of COVID-19 vaccines in real-world settings. These questions can only be answered in post-introduction vaccine effectiveness studies.This guidance document outlines an approach to leverage existing surveillance systems for Severe Acute Respiratory Infection (SARI) to estimate COVID-19 vaccine effectiveness (VE) in preventing SARI associated with laboratory-confirmed SARS-CoV-2 using  existing SARI  surveillance  systems. The  approach  uses  the test-negative  design  to  evaluate  VE;  cases  are  SARI  patients  who  tested  positive  for  SARS-CoV-2,  and controls are SARI patients who tested negative for SARS-CoV-2.