Question
DPT vaccine
Answer
DPT vaccine is a combination vaccine protecting against Diphtheria, Pertussis (whooping cough), and Tetanus — a cornerstone of routine national immunization schedules worldwide.
Components: diphtheria toxoid and tetanus toxoid (both formalin-inactivated exotoxins, immunogenic but non-toxic), combined with a pertussis component, either whole-cell (wP) — killed whole Bordetella pertussis, more reactogenic but robust immunity — or acellular (aP) — purified specific pertussis antigens, with a more favourable side-effect profile.
Schedule: a primary series of 3 doses in infancy, followed by booster doses (typically 18 months and around 5 years); a Tdap booster during pregnancy protects the neonate via passive maternal antibody transfer.
Mechanism: stimulates active immunity — antitoxin antibody against diphtheria and tetanus toxins, and antibody/cellular immunity against pertussis antigens.
Adverse effects: local reactions common, especially with whole-cell pertussis vaccine; rare serious reactions historically prompted development of the acellular alternative.