COVID-19 Vaccination Recommendations for a 9-Month-Old Infant (2024-2025)
For a 9-month-old infant, the 2024-2025 COVID-19 vaccination recommendation is to receive an initial multidose series of either 2 doses of Moderna or 3 doses of Pfizer-BioNTech COVID-19 vaccine, with at least one dose being the 2024-2025 formulation. 1
Detailed Vaccination Schedule Based on Previous Vaccination Status
For Unvaccinated Infants (6 months-4 years):
- Moderna option: 2 doses of 2024-2025 formulation with 4-8 weeks between doses
- Pfizer-BioNTech option: 3 doses of 2024-2025 formulation with 3-8 weeks between doses 1 and 2, and ≥8 weeks between doses 2 and 3
For Previously Vaccinated Infants:
- If previously received 1 dose of Moderna: 1 additional dose of 2024-2025 Moderna vaccine 4-8 weeks after dose 1
- If previously received ≥2 doses of Moderna: 1 dose of 2024-2025 Moderna vaccine ≥8 weeks after last dose
- If previously received 1 dose of Pfizer-BioNTech: 2 additional doses of 2024-2025 Pfizer-BioNTech vaccine (3-8 weeks between doses 1 and 2, ≥8 weeks between doses 2 and 3)
- If previously received 2 doses of Pfizer-BioNTech: 1 additional dose of 2024-2025 Pfizer-BioNTech vaccine ≥8 weeks after dose 2
- If previously received ≥3 doses of Pfizer-BioNTech: 1 dose of 2024-2025 Pfizer-BioNTech vaccine ≥8 weeks after last dose
Special Considerations for Immunocompromised Infants
For infants who are moderately or severely immunocompromised:
- If unvaccinated: 3-dose series of 2024-2025 mRNA COVID-19 vaccine (all doses from same manufacturer)
- Additional doses may be recommended based on clinical judgment if already vaccinated
Clinical Importance and Effectiveness
The Advisory Committee on Immunization Practices (ACIP) voted 11-0 (with one abstention) to recommend 2024-2025 COVID-19 vaccines for all persons aged ≥6 months 1. This strong consensus reflects the importance of vaccination for reducing COVID-19-associated morbidity and mortality.
While specific effectiveness data for the 2024-2025 vaccines in infants is not yet available, interim estimates from the 2024-2025 vaccine in adults show effectiveness of 33-46% against COVID-19-associated emergency department/urgent care visits and hospitalizations 2. The 2023-2024 formulation showed modest protection that waned over time 3, 4, highlighting the importance of updated formulations targeting current circulating variants.
Important Implementation Considerations
- Ensure the correct age-appropriate dosage is administered (dosages for infants differ from those for older children and adults)
- If a lower dose than recommended is inadvertently administered, an additional dose should be given to provide the full recommended dose as soon as possible
- When two doses are recommended in a given season, they do not need to be the same brand
- Vaccination should be offered as soon as it becomes available for optimal protection
Common Pitfalls to Avoid
- Incorrect dosing: Infant doses are different from adult doses - verify the correct formulation and dose for the 9-month-old
- Inadequate series completion: Ensure the full recommended series is completed (2 doses for Moderna, 3 doses for Pfizer-BioNTech)
- Inappropriate intervals: Follow the recommended intervals between doses (4-8 weeks for Moderna, 3-8 weeks between first two Pfizer doses)
- Mixing vaccine types incorrectly: While different brands can be used in a series, ensure appropriate scheduling based on which vaccines were previously received
The 2024-2025 COVID-19 vaccines target the Omicron JN.1 lineage (JN.1 and KP.2), which are the currently predominant variants, providing better protection against circulating strains compared to previous vaccine formulations.