Influenza and nursing homes.

Sequential Outbreak of Influenza A and B in a Nursing Home: Efficacy of Vaccine and Amantadine

“…Although some reports, including previous studies from our program, indicate that influenza vaccine reduced the incidence and severity of influenza virus infections in nursing home populations, 5–7 other studies did not demonstrate any protective effect 8,9 . Explanations for this failure include insufficient vaccine potency, inadequate immune response to the vaccine by debilitated patients, low levels of vaccination in the nursing home, 8,10 and antigenic drift from the strain that had been included in the vaccine 11…”