Guidance on the use of COVID-19 vaccines in the fall of 2023

On January 20, 2023, the National Advisory Committee on Immunization (NACI) published Guidance on COVID-19 vaccine booster doses: Initial considerations for 2023, followed by Guidance on an additional COVID-19 booster dose in the spring of 2023 for individuals at high risk of severe illness due to COVID-19 on March 3, 2023.

Since then, the World Health Organization (WHO) has determined that COVID-19 is an established and ongoing health issue and no longer constitutes a public health emergency of international concern (1) . Transition to the long-term management of the COVID-19 pandemic is now needed, but there continue to be uncertainties such as the ongoing epidemiology of COVID19, duration of protection from current COVID-19 booster doses and previous infection, and vaccine effectiveness (VE) of future vaccines.

On May 18, 2023, the WHO Technical Advisory Group on COVID-19 Vaccine Composition (TAGCO-VAC) released recommendations for updates to COVID-19 vaccine antigen composition (2) . An approach recommended by TAG-CO-VAC is a monovalent XBB.1 descendent lineage, such as XBB.1.5 or alternatively XBB.1.16. The International Coalition of Medicines Regulatory Authorities (ICMRA), European Centre for Disease Prevention (ECDC), the European Medicines Agency (EMA), and the US Food and Drug Administration Vaccines and Related Biological Products Advisory Committee (FDA VRBPAC) have also released decisions supporting XBB as a candidate for the COVID-19 vaccine composition update. Manufacturers have indicated that new COVID-19 vaccine formulations are in development and products are forthcoming.

Although seasonality of SARS-CoV-2 has not been established, other respiratory viruses such as influenza and respiratory syncytial virus (RSV) typically increase in the fall and winter months. To help reduce the impact of COVID-19 on the health system while other respiratory viruses are circulating and with the expected availability of a new COVID-19 vaccine formulation, NACI is providing guidance on the use of COVID-19 vaccines to inform planning for a vaccination program starting in fall 2023.