Prevaccination antibody titers can estimate the immune response to influenza vaccine in a rural community-dwelling elderly population

► Antibody response was investigated in rural community-dwelling elderly persons. ► Both age and vaccination in the previous year were not related to antibody response. ► Those with low antibody titer before vaccination were defined as 'seronegative'. ► 'Seronegative' persons do not acquire enough antibody with one dose of vaccine. ► Future trials should be performed to determine if a second shot maintains the titer.