Geneva, Switzerland – The World Health Organization, with the support of the Strategic Advisory Group of Experts (SAGE) on Immunization and its COVID-19 Vaccines Working Group, continues to review the emerging evidence on the need for and timing of a booster dose for the currently available COVID-19 vaccines which have received Emergency Use Listing (EUL).
This statement reflects the current understanding of vaccine performance and supply as presented to SAGE on 7 December 2021. It summarizes and contextualizes current evidence on booster vaccination. In recent weeks the SARS-CoV2 Omicron variant has emerged. Data are currently insufficient to assess the impact of this new variant of concern on vaccine effectiveness, in particular against severe disease. The statements and conclusions in this document will therefore be updated as data become available.