Methods: In this pragmatic, comparative effectiveness, cluster-randomized trial, enrolled NHs were randomized to administer either HD or SD vaccine to long stay residents for the 2013-14 season. Facilities were also allocated to free vaccine for staff or usual procedure in a 2x2 factorial design. Data were collected from CMS under data-use agreements and from enrolled facilities. All analyses were by Intent-To-Treat. We analyzed hospitalization incidence using marginal Poisson regression accounting for clustering of residents within facilities, and adjusting for a priori facility and resident covariates. We analyzed secondary outcomes (mortality, activities of daily living) using Cox proportional hazards and logistic regression.
Results: We randomized 823 facilities with 53,008 long stay residents; facility and resident characteristics were similar between arms. Flu A/H1N1 was the dominant flu strain during the study period. Incidence of hospitalization was significantly lower in HD than SD facilities for all-causes (Adjusted RR=0.951, 95% CI 0.907-.996, p=0.0347) and respiratory conditions (ARR=0.883, CI 0.787-0.989, p=0.032) and lower but NS so for pneumonia and influenza.
Conclusion: High dose flu vaccine reduces risk of all-cause hospitalization and hospitalization for respiratory conditions in long-term care residents in an A/H1N1 dominant season.
Funding: Sanofi Pasteur
M. Taljaard, None
J. Ogarek, Sanofi: analyst , Research support
L. Han, Sanofi: Investigator , Grant recipient , Research grant and Research support
R. Dahal, Sanofi: analyst , Research support
P. Gozalo, Sanofi: Grant Investigator , Research support
V. Mor, Sanofi: Grant Investigator , Research grant and Research support