The pertussis vaccine is a type of attenuated live vaccine, which clinically is mainly part of a combination vaccine that includes pertussis, diphtheria, and tetanus, commonly referred to as the DTP vaccine. Normally, a baby should receive the first dose at three months of age, followed by the second dose in the fourth and fifth months, as part of basic immunization. Between the age of eighteen months and two years, another dose is administered to boost immunity, which after producing lifelong antibodies, prevents reinfection with the disease.