Prevention and control of type A influenza infections in nursing homes. Benefits and costs of four approaches using vaccination and amantadine.

We developed a model to project morbidity, mortality, and costs attributable to type A influenza virus infections in nursing homes and to evaluate the relative benefits and costs of programs for prevention and control. Influenza vaccination was the most cost-effective intervention under various simulations in the model but usually allowed for higher rates of morbidity and mortality compared with other alternatives. The combined use of previous vaccination and chemoprophylaxis during outbreaks in the nursing home was associated with significantly fewer cases than use of vaccination alone, with only modest increases in net program costs. The use of chemoprophylaxis throughout the influenza season (without vaccination) resulted in the fewest number of illnesses, hospitalizations, and deaths but would cost at least 650% more than alternatives involving vaccination. Regardless of which strategy is chosen, our model suggests that influenza control programs in nursing homes are both beneficial and cost-effective and should be considered a part of standard care.