Recombinant vs Egg-Based Quadrivalent Influenza Vaccination for Nursing Home Residents: A Cluster Randomized Trial

Area of Science:

• Gerontology
• Vaccinology
• Infectious Diseases

Background:

• Influenza vaccination is crucial for preventing illness and death in nursing home residents.
• Recombinant influenza vaccine effectiveness is known in outpatients but not yet in nursing home populations.

Purpose of the Study:

• To compare hospitalization rates in nursing home residents vaccinated with recombinant versus standard-dose influenza vaccines.

Main Methods:

• A pragmatic cluster randomized trial involving 1078 nursing homes and over 144,000 residents.
• Nursing homes were assigned to administer either recombinant quadrivalent influenza vaccine (RIV4) or standard egg-based quadrivalent inactivated influenza vaccine (IIV4).
• Resident-level hospitalization outcomes were evaluated using Medicare claims data.

Main Results:

• No significant difference in respiratory-related hospitalizations between RIV4 and IIV4 groups (1.9% vs 2.0%).
• Similar rates for other hospitalization outcomes and death across both vaccine groups.
• Comparable baseline characteristics and outcomes across subgroups and seasons.

Conclusions:

• Recombinant and standard-dose influenza vaccines showed no significant difference in reducing hospitalizations in nursing home residents.
• Conclusions are limited by the COVID-19 pandemic's impact on influenza activity and poor vaccine strain match.