The Tdap vaccine can protect adolescents and adults against tetanus, diphtheria and pertussis (whooping cough). Td (Tetanus Booster) vaccine can protect against tetanus and diphtheria, and has been used for many years as booster doses for adolescents and adults.d (Tetanus Booster) vaccine can protect against tetanus and diphtheria, and has been used for many years as booster doses for adolescents and adults.