EU agencies back Covid-19 vaccine update ahead of autumn campaign

Covid-19 vaccine compositions should be updated to provide protection against XBB Omicron variant strains in preparation for the autumn vaccination campaign, say EU agencies in a joint 6 June statement.

This reflects decisions made at past meetings by members of the International Coalition of Medicines Regulatory Authorities on 8 May and elsewhere. There, organisations determined that the compositions of Covid-19 vaccines need to be updated to reflect the evolution of the virus.

The vaccines approved for use in the EU currently provide protection against strains such as bivalent Wuhan and Omicron BA. A, among others. While available data shows that the approved vaccines protect against severe disease, their immunogenicity fades as Covid-19 mutates into immunologically distant variants from strains included in the vaccines, per the 6 June statement.

According to the European Centre for Disease Prevention and Control (ECDC) and the European Medicines Agency (EMA), which issued the announcement, a monovalent vaccine composition should provide adequate immunogenicity against Covid-19 in primed and naïve individuals. However, it is not necessary to include both the ancestral strain and past variants of concern in the vaccine formulation as they now represent only an “extremely small proportion of circulating strains in the EU/EEA countries”.

Instead, the composition should feature a strain that is part of the XBB Omicron subvariant family, which would be enough to maintain cross-reactivity against dominant and emerging strains. Specifically, the XBB.1.5 strain represents a valid choice that broadens the degree of immunity against XBB descendent lineages.

The guidance comes after the EMA and European medicines regulatory network lifted Covid-19 business continuity measures, last month.

A platform approach would be appropriate when it comes to changing vaccine composition to tackle new strains. Subsequent approval decisions can be done based on manufacturing and non-clinical data if the platform showcases predictable clinical immunogenicity. This data can be “based on different variants of concerns that have been previously investigated”.

The joint statement also includes recommendations on the population that should be targeted. The upcoming autumn campaign should prioritise those at risk of progression to severe disease like adults above 60 years of age, immunocompromised individuals, and pregnant women. Additionally, individuals with underlying medical conditions should be prioritised without considering their age. The statement identifies several other groups of at-risk individuals, like elderly populations above the age of 80 who received their vaccine four months or longer, and children of a certain age and vaccination history for prioritisation and administration of the vaccine.