NS1-truncated live attenuated virus vaccine provides robust protection to aged mice from viral challenge.

Immunological changes associated with age contribute to the high rates of influenza virus morbidity and mortality in the elderly. Compounding this problem, aged individuals do not respond to vaccination as well as younger, healthy adults. Efforts to increase protection to this demographic group are of utmost importance, as the proportion of the population above the age of 65 is projected to increase in the coming decade. Using a live influenza virus with a truncated nonstructural protein 1 (NS1), we are able to stimulate cellular and humoral immune responses of aged mice comparable to levels seen in young mice. Impressively, a single vaccination provided protection following stringent lethal challenge in aged mice.