With input from the COVID-19 Vaccine Composition Technical Advisory Group (TAG-CO-VAC) and the World Health Organization (WHO), the Strategic Advisory Group of Immunization (SAGE) underscored two core aims: vaccines should protect against serious illness and death across all variants.
Priority remains achieving high coverage of the primary vaccination series and booster doses in the highest usage groups, with a clear warning that new variants will continue to emerge in all countries.
In addition, incorporating the Omicron variant into a modified vaccine formulation administered as a booster is expected to become common practice. This approach aims to bolster immunity while preserving protection against serious illness and death.
Approval from a WHO emergency use listing or a stringent regulatory authority for a vaccine with a modified composition will enable SAGE to issue policy recommendations for its use.
The main goal of COVID-19 vaccination is to reduce hospitalizations and serious illness, and to safeguard health systems. Vaccines currently licensed based on the original index virus—identified from cases in December 2019—continue to provide strong protection against severe disease across all variants, including boosters targeting the original strain.
There is ongoing and significant evolution of SARS-CoV-2 since late 2019, and this evolution is expected to continue, potentially yielding new variants with changes in the spike protein. The path of future variants remains unclear, and their exact characteristics cannot yet be predicted.
Given these uncertainties, it may be prudent to pursue an additional COVID-19 vaccination target to achieve broader immunity against circulating and emerging variants while maintaining protection against serious illness and death, according to WHO.
Available data suggest that including Omicron, the most antigenically distinct variant of concern, in an updated vaccine composition could be beneficial when given as a booster to individuals who have completed a primary vaccine series against COVID-19.
Vaccine divalent
On the European front, the European Medicines Agency (EMA) is conducting an ongoing review of a Moderna COVID-19 vaccine adapted to offer better protection against circulating variants.
The review centers on the bivalent vaccine developed by Moderna, designed to target two strains of SARS-CoV-2: the original strain and the Omicron variant.
The EMA analysis will initially concentrate on non-clinical data and chemistry, manufacturing, and controls for the vaccine. As Moderna progresses, the EMA will receive additional data, including immune response information to both the original and Omicron strains.
As the continuous review proceeds, the EMA can evaluate new data as it becomes available. The investigation will continue until sufficient information exists for Moderna to file an official authorization request.
Ultimately, the composition of vaccines adapted to new variants will depend on guidance from public health authorities and the World Health Organization, as well as assessments by regulatory bodies such as the EMA and other members of the International Coalition of Medicines Regulatory Authorities (ICMRA).