Booster influenza vaccination confers additional immune responses in an elderly, rural community-dwelling population.

This study aimed to examine the effects of a booster vaccination in elderly people using 2 doses of trivalent inactivated influenza vaccine during the 2012-2013 influenza epidemic. Seroprotection rates against the A(H1N1)pdm09 strain in younger elderly people (aged 61-75 years) and the A(H3N2) and B strains in both younger elderly people (aged 61-75 years) as well as very elderly people (aged 76-102 years) did not decrease at 22 weeks after vaccination. This approach confers long-lasting antibody responses and may be useful in clinical practice.