Vaccines used today protect against diphtheria and tetanus (ie, DT and Td) and also include protection against pertussis (ie, DTaP and Tdap). Infants and children under 7 years of age should receive either DTaP or DT, while older children and adults should receive either Tdap or Td. However, regardless of the vaccine, a booster dose of diphtheria-tetanus-pertussis vaccine is always needed to ensure lifelong immunity.