The WHO does not rule out updating the composition of current vaccines against COVID-19

The Technical Advisory Group on the Composition of the Vaccine against COVID-19 (TAG-CO-VAC) of the World Health Organization (WHO) has recognized that it may be necessary to update the composition of current vaccines against covid, due to its continuous evolution and the possible appearance of new variants, to maintain protection against disease, while ensuring the breadth of the immune response against circulating and emerging variants.

The TAG-CO-VAC has considered that there are heterogeneous levels of population immunity between countries due to the different waves and “The performance of any updated vaccine may vary depending on the nature and extent of previously acquired immunity,” points out.

In this way, they affirm that, when updated vaccines become available, a substantial proportion of the world population will have been exposed to SARS-CoV-2, either as a result of vaccination and/or previous infection. There are also considerable uncertainties about how the virus will continue to evolve and the antigenic characteristics of future variants. Given the widespread transmission of Omicron globally, the possibility of its continued evolution is high and a new variant may emerge before it can be produced and

They also state that they are looking for evidence of robust homologous immune responses in primed and unprimed individuals and cross-reactivity data in primed individuals.

Currently, the epidemiological situation, the WHO points out, is characterized by a rapid and relatively synchronous dominance of the Omicron variant. “While global cases are declining, there are reduced testing resources and capacities in some areas and the epidemiological situation remains heterogeneous, with several regions and countries reporting increases in new weekly cases while others are now reporting decreases.”the WHO has assured.

The Omicron variant is made up of several sublineages, such as BA.1, BA.2, and BA.3. Globally, BA.1 has been the predominant Omicron lineage, however the proportion of reported sequences designated BA.2 has increased relative to BA.1 in recent weeks, and

“BA.1 and BA.2 have some genetic differences, which may make them antigenically distinct. Reinfection with BA.2 after infection with BA.1 has been documented; however, initial data from population-level studies suggest that infection with BA.1 provides substantial protection against reinfection with BA.2, at least for the limited period for which data are available.” detailed by the WHO.

Ultimately, the WHO concludes that they continue to review and assess the public health implications of emerging SARS-CoV-2 Variants of Concern on vaccine performance.