The FDA approved and authorized updated mRNA COVID-19 vaccines for 2024-2025, targeting the Omicron variant KP.2 strain. The monovalent vaccines, manufactured by ModernaTX Inc. and Pfizer Inc., aim to provide enhanced protection against current circulating variants and reduce serious COVID-19 outcomes.

Key points

1. Approved vaccines: Comirnaty and Spikevax for individuals 12 years and older
2. Authorized vaccines: Moderna and Pfizer-BioNTech for ages 6 months through 11 years
3. Dosing schedule varied based on age and vaccination history
4. Additional doses authorized for certain immunocompromised individuals

The FDA's decision followed the agency's June 2024 recommendation for monovalent JN.1 vaccines, which was later updated to the KP.2 strain due to SARS-CoV-2 evolution and increased COVID-19 cases. Peter Marks, MD, PhD, director of the FDA's Center for Biologics Evaluation and Research, emphasized the importance of vaccination in COVID-19 prevention and encouraged eligible individuals to consider receiving the updated vaccine.

Vaccination Schedule

The FDA provided detailed guidance on vaccine administration:

1. Unvaccinated children 6 months to 4 years:
   • Pfizer-BioNTech: 3 doses
   • Moderna: 2 doses
2. Previously vaccinated children 6 months to 4 years:
   • 1 or 2 doses of either vaccine (timing and number depending on previous vaccination)
3. Ages 5-11 years:
   • Single dose of either vaccine, regardless of vaccination history
   • If previously vaccinated, administered 2 months or more after last COVID-19 vaccine
4. Ages 12 years and older:
   • Single dose of Comirnaty or Spikevax
   • If previously vaccinated, administered 2 months or more after last COVID-19 vaccine

Safety and Efficacy

The FDA's approval process included an assessment of manufacturing and nonclinical data. The updated vaccines were produced using processes similar to those of previous formulations. Side effects were expected to be comparable to those reported with earlier mRNA COVID-19 vaccines.

The agency anticipated that the composition of COVID-19 vaccines would require annual assessment, similar to seasonal influenza vaccines, barring the emergence of a significantly more infectious SARS-CoV-2 variant.

Additional Data and Considerations

1. Vaccine Evolution: The FDA initially advised manufacturers in early June 2024 to develop monovalent JN.1 vaccines. However, due to the rapid evolution of SARS-CoV-2 and a subsequent increase in COVID-19 cases, the agency updated its recommendation to target the KP.2 strain.
2. Population Impact: The FDA noted that waning immunity in the population, both from previous virus exposure and prior vaccination, necessitated the updated vaccines to maintain effective protection against currently circulating variants.
3. Historical Context: The mRNA COVID-19 vaccines had been administered to hundreds of millions of people in the United States prior to this update, with the benefits consistently outweighing the risks.
4. Immunocompromised Patients: The FDA authorized additional doses for certain immunocompromised individuals ages 6 months through 11 years, as detailed in the Moderna COVID-19 Vaccine and Pfizer-BioNTech COVID-19 Vaccine fact sheets.
5. Manufacturing Process: The updated mRNA vaccines utilized a manufacturing process similar to that of previous formulations, ensuring consistency in production and quality control.
6. Regulatory Flexibility: The FDA committed to ongoing review of additional COVID-19 vaccine applications, indicating a readiness to adapt to future viral mutations or public health needs.
7. Age-Specific Approvals:
   • Comirnaty and Spikevax: Approved for individuals 12 years of age and older
   • Moderna COVID-19 Vaccine and Pfizer-BioNTech COVID-19 Vaccine: Authorized for emergency use in individuals 6 months through 11 years of age
8. Potential for Future Updates: The FDA anticipated that, barring the emergence of a markedly more infectious variant, the composition of COVID-19 vaccines would likely need annual assessment, mirroring the approach taken with seasonal influenza vaccines.

Regulatory Process

The FDA granted approval of Comirnaty (2024-2025 Formula) to BioNTech Manufacturing GmbH and issued an Emergency Use Authorization (EUA) amendment for the Pfizer-BioNTech COVID-19 Vaccine (2024-2025 formula) to Pfizer Inc. Similarly, Spikevax (2024-2025 formula) approval was granted to ModernaTX Inc., with an EUA amendment for the Moderna COVID-19 Vaccine (2024-2025 formula) issued to the same company.