High Dose Influenza Vaccination and Morbidity & Mortality in U.S. Nursing Homes

SUMMARY: This nationally representative study samples from estimated 6782 Medicare-certified nursing homes co-located within 50 miles of the 122 cities reporting to Center for Disease Control and Prevention (CDC) weekly influenza surveillance. In total, 1000 facilities will be enrolled for random assignment to either: 1) the licensed high dose (HD) trivalent influenza vaccine (High-Dose Fluzone [HD vaccine]), or 2) the standard dose (SD) trivalent influenza vaccine (Fluzone [SD vaccine]) for their residents. Additionally, half the facilities will receive free SD vaccine for their staff and the remaining facilities will practice usual care (no free vaccine) for staff. BACKGROUND: Influenza and pneumonia (P&I) are leading infectious causes of hospitalization and mortality in community-dwelling older adults and residents of long-term custodial care facilities or nursing homes (NH), and produce substantial annual health care costs. The elderly incur over 90% of this disease burden and NH residents are especially vulnerable given immune senescence, multimorbidity, and close living quarters. While hospitalization rates for NH residents vary considerably between facilities, most occur during the sixteen weeks of peak influenza activity annually. Influenza vaccination, a mainstay in prevention, is recommended in the U.S. for all individuals six months of age and older. Vaccination associates with reduced rates of stroke, heart attack, hospitalization, and death in non-institutional older adult populations. However, the benefit of influenza vaccine for the elderly in general has been questioned, a salient concern for frail elderly, such as NH residents. Influenza vaccination rates vary substantially between nursing homes. Influenza vaccine response declines with advancing age, indicating the need for a better vaccine. OBJECTIVES: The primary objective is to estimate the differences in all-cause hospitalization rates during influenza season experienced by long-stay nursing home residents, between facilities using HD vaccine vs. SD vaccine. The secondary objective is to estimate the differences in the likelihood of Activities of Daily Living (ADL) functional decline and mortality rates in the study nursing homes.