Can Quadrivalent and Trivalent Influenza Vaccines Be Given Together?
No, quadrivalent and trivalent influenza vaccines should not be administered together in the same season—only one influenza vaccine formulation should be given per season. 1
Rationale for Single Vaccine Administration
One dose per season is the standard: All major guidelines from the Advisory Committee on Immunization Practices (ACIP) and the American Academy of Pediatrics specify that individuals receive a single influenza vaccination per season, regardless of whether it is trivalent or quadrivalent. 1
No clinical benefit to dual administration: There is no evidence supporting additional protection from administering both formulations, and doing so would expose patients to unnecessary antigens and potential adverse events without added benefit. 1
Choosing Between Trivalent and Quadrivalent Formulations
When both formulations are available and age-appropriate, either can be used with no preference expressed by ACIP or AAP. 1
Key Decision Points:
Quadrivalent vaccines offer broader B-lineage coverage: QIV contains both B/Victoria and B/Yamagata lineage strains, while TIV contains only one B lineage, potentially offering improved protection when both B lineages are circulating. 1
Current 2024-2025 season context: All U.S. influenza vaccines for 2024-2025 are trivalent formulations (containing A/H1N1, A/H3N2, and B/Victoria only) because the B/Yamagata lineage has disappeared globally, making quadrivalent formulations unnecessary. 2
Age-specific considerations: Both formulations have similar safety profiles across age groups when appropriately licensed, with comparable rates of injection-site reactions and systemic symptoms. 1, 3, 4
Common Pitfalls to Avoid
Do not delay vaccination to obtain a specific formulation: When an age-appropriate vaccine is available, administer it promptly rather than waiting for a preferred formulation. 1, 2
Do not administer a second dose of a different formulation: If a patient receives TIV and later requests QIV (or vice versa) in the same season, do not revaccinate—the initial dose provides adequate protection. 1
Verify age-appropriate products: Ensure the specific vaccine product is licensed for the patient's age group, as different formulations have different age indications (e.g., some QIV formulations are approved for children as young as 6 months, while others have different lower age limits). 1
Special Populations
Children 6 months through 8 years requiring two doses: These children need two separate doses of the same or different influenza vaccine formulations administered at least 4 weeks apart based on their vaccination history, but both doses should be from the current season's available vaccines—not a combination of current and previous season vaccines. 1
Adults 65 years and older: Should receive either standard-dose or high-dose formulations as appropriate, with no preference between trivalent and quadrivalent when both are available and age-appropriate. 5, 3