A global agreement on a strategy to adapt COVID-19 vaccines to emerging variants was reached in early May, according to a statement issued by the European Medicines Agency (EMA). The current vaccines offer protection from severe illness, hospitalisation, and death, but waning protection over time, the continued evolution of the virus, and the emergence of new SARS-CoV-2 variants underscore the need for global coordination to facilitate vaccination policies, implementation by providers, and vaccine uptake and compliance by at-risk populations.
The agreement came about after the 4th meeting of the International Coalition of Medicines Regulatory Authorities (ICMRA) vaccines workshop, which was co-chaired by the EMA and the United States Food and Drug Administration (FDA) on 8 May 2023. Findings from the meeting report highlighted preliminary data demonstrating that the COVID-19 vaccines adapted to currently circulating strains improve immunity to newer variants of concern, such as XBB lineages. So, any update to the COVID-19 vaccine antigen composition will be geared toward achieving broad immunity rather than targeting the most recent circulating variant. For the upcoming winter season in the northern hemisphere, vaccines should include only one virus strain and be based on the XBB family of Omicron subvariants. Monovalent vaccines could be used for both boosters and primary vaccination in children aged <4 to 5 years.
In his presentation to ICMRA members, Marco Cavaleri, PhD, Head of EMA’s Biological Health Threats and Vaccine Strategy, shared data showing that most of the burden of SARS-CoV-2-related disease is condensed in the winter months even though seasonality has not been firmly established. Similar to other human coronaviruses (which peak annually between January and February), SARS-CoV-2 is likely to follow a similar pattern.
Cavaleri also noted that not all EU-approved vaccine platforms will be able to provide adapted vaccines this year. However, coalition members reached broad agreement that in the future, EMA will issue recommendations around April/May to allow for timely autumn vaccination campaigns. The FDA plans to follow suit, according to workshop co-chair Peter Marks, MD, PhD, Director of the Center for Biologics Evaluation and Research at the FDA, who said that plans for annual strain selection will occur around May to allow for a vaccine rollout in the fall that aligns with the influenza vaccine.
Importantly, ICMRA members emphasised that different countries/regions have flexibility in terms of vaccine strain update, with considerations focused on vaccine availability as well as the ability to demonstrate adequate effectiveness with existing composition. Data on manufacturing, laboratory findings, and vaccine quality will be required for authorisation or approval of vaccine strain changes to already approved COVID-19 vaccines, provided that post-authorisation data regarding quality, safety, effectiveness, and immunogenicity are provided.