Safe and effective vaccines have proven efficacious in combating COVID-19. However, most COVID-19 vaccine products which received emergency use authorization from WHO had been approved for use based on data from random control trials. This is while observational studies were needed to measure vaccine effectiveness against specific outcomes, in particular subpopulations, for different severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and vaccine products. In addition to fewer vaccine effectiveness studies being conducted in the Region, there were also unique vaccine products that were manufactured domestically and only approved for use in certain counties. This resulted in limited regional and national data on COVID-19 vaccine effectiveness, creating a gap of knowledge that was essential for informing COVID-19 immunization policies for the Region.
Considering the methodological complexities and limited capacity for conducting vaccine effectiveness studies in the Region, the WHO Regional Office decided to support Member States through launching a regional COVID-19 vaccine effectiveness study. The main objectives of this study were to ensure the reliability and quality of data from national studies, while allowing pooling of results across countries and over time. This would not only increase the statistical power and accuracy of results, but also allow reporting regional vaccine effectiveness estimates. The regional study started in September 2021 and is currently ongoing. The statistical analyses of final results from the regional study are ultimately anticipated to help understand vaccine impact and inform evidence-based policy-making for regional immunization programmes.