The U.S. Food and Drug Administration (FDA) has given the go-ahead for two updated Covid-19 vaccines based on messenger RNA (mRNA) technology, permitting these new versions to soon become available to the public. The timing of this release, as the fall respiratory illness season approaches, could not be more opportune, providing a fresh line of defense against current Covid-19 variants.
Originally, the FDA had approved Covid-19 vaccines from partners Pfizer and BioNTech, as well as Moderna, for use in adults. This recent FDA announcement extends the approval to include an updated version of these vaccines. What this means is that these vaccines are now also authorized for infants as young as six months and children up to 17 years old—an age group that previously only had access to the Covid-19 vaccine under emergency use authorizations. [FDA]
A notable exception was Novavax’s protein-based vaccine—the only non-mRNA Covid-19 vaccine available in the U.S. As of the FDA announcement, this updated vaccine is still under FDA review for emergency use authorization in people aged 12 and older. [Novavax]
The advantage of mRNA vaccine technologies is that they can effectively address multiple variants with a single shot—an approach that was taken with the most recent round of booster shots. These were designed to combat the original strain along with the Omicron variant. However, the updated vaccines which were approved and authorized on Monday are monovalent shots, meaning they were designed with a single component targeting the Omicron variant XBB.1.5.
The FDA has ruled in favor of these XBB.1.5 monovalent vaccines based on current evidence and past recommendations of an advisory committee. However, CDC’s latest data indicate that a different Omicron subvariant, EG.5, accounts for 21.5% of all cases, making it the most prevalent variant. Recent studies from BioNTech and Moderna found that these updated vaccinations neutralized this strain along with another variant, BA.2.86. These promising results suggest that the vaccines are well suited to defend against currently circulating Covid-19 variants. The FDA anticipates yearly vaccine updates in line with current industry practices and the public’s familiarization with the schedule. [CDC] [BioNTech] [Moderna]
Changes to dosing schedules are among the regulatory actions from FDA. Initially, both mRNA vaccines were approved as a series of two shots, spaced weeks apart for those aged 12 and older. Approval of the updated vaccine, however, shifts the dosing schedule to a single shot for persons aged 12 and up. The minimum age for a single dose of the Moderna vaccine has been dropped from age 6 to age 5. For both mRNA vaccines, certain immunocompromised children from 6 months to 11 years old may be considered for additional doses.
The upcoming agenda for the Advisory Committee on Immunization Practices (ACIP), a consultative body to the CDC, will include detailed discussions on who should receive these vaccines. Moderna and Pfizer forecast that the updated versions of their respective Covid-19 vaccines could become available in pharmacies and other healthcare settings in the coming days, subject to the CDC director’s final sign-off. [ACIP] [Moderna] [Pfizer/BioNTech]