On Tuesday (April 18), the United States Food and Drug Administration (FDA) revoked the authorisation of ‘monovalent’ Moderna and Pfizer-BioNTech vaccines, which were earlier in use against Covid-19.
In a statement, it said, “The monovalent Moderna and Pfizer-BioNTech COVID-19 vaccines are no longer authorized for use in the United States.”
Meanwhile, FDA has authorised ‘bivalent’ vaccines to be used for all doses given to individuals 6 months of age and older. It must be mentioned that ‘monovalent’ vaccines contain only one strain of a virus whereas ‘bivalent’ vaccines contain two strains of the virus.
The current bivalent Covid-19 vaccines, approved by the US Food and Drug Administration, contain both original and Omicron BA.4/BA.5 strains. Given that the virus that causes Covid-19 has mutated over the years, the efficacy of the monovalent vaccine (containing only the original strain) had reduced.
According to the Washington State Department of Health, initial data [pdf] has shown that bivalent Covid-19 boosters provided broader protection than monovalent boosters.
While speaking about the matter, Peter Marks said, “At this stage of the pandemic, data support simplifying the use of the authorized mRNA bivalent COVID-19 vaccines and the agency believes that this approach will help encourage future vaccination.”
Marks, who serves as the Director of the FDA’s Center for Biologics Evaluation and Research, added, “Evidence is now available that most of the U.S. population 5 years of age and older have antibodies to SARS-CoV-2, the virus that causes COVID-19, either from vaccination or infection that can serve as a foundation for the protection provided by the bivalent vaccines.”