Aging and the Immune Response to Tetanus Toxoid: Diminished Frequency and Level of Cellular Immune Reactivity to Antigenic Stimulation

The period of efficacious immune reactivity afforded by tetanus immunization and the need for continuing some forms of tetanus vaccination programs have been the subjects of recent debates. Our studies demonstrate that the level of antitetanus immunity based on immunological memory (i.e., cellular immune responsiveness) varies dramatically as a function of age, with older individuals constituting a population which is increasingly susceptible to tetanus infection.