New Antigen Composition Advised for COVID-19 Vaccines

The World Health Organization (CDC) Technical Advisory Group for COVID-19 Vaccine Composition today announced its advice on the composition of future formulations of COVID-19 vaccines.

The objective of an update to COVID-19 vaccine antigen composition is to enhance vaccine-induced immune responses.

Updating the vaccine composition considers the evolution of the SARS-CoV-2 beta coronavirus variants and aims to improve protection against symptomatic disease.  

The Group suggests that future formulations of COVID-19 vaccines use newer variants in their composition, i.e., XBB.1 descendant lineages.  

As of May 2023, the XBB.1 descendent lineages currently predominate globally (i.e., XBB.1.5, XBB.1.16, XBB.1.9).

Furthermore, estimates of vaccine efficacy (VE) against currently circulating SARS-CoV-2 variants, including XBB.1 descendent lineages, are very limited in terms of the number of studies, vaccine products evaluated, and populations assessed; some studies show similar VE against BA.5 descendent and XBB.1 descendent lineages, while others suggest reduced VE during periods of the predominance of XBB.1 descendent lineages.

Additionally, the TAG-CO-VAC continues to encourage the further development of vaccines that enhance mucosal immunity because they may improve protection against infection and reduce transmission of SARS-CoV-2, in alignment with the WHO Global COVID-19 Vaccination Strategy, published in July 2022. 

On May 18, 2023, the WHO stated the current COVID-19 vaccines continue to be highly protective against severe disease and death. 

And the WHO strongly encourages the use of available authorized COVID-19 vaccines, which include the index SARS-CoV-2 virus, according to recommendations from the Strategic Advisory Group of Experts on Immunization, updated in March 2023.