The diphtheria, tetanus, and pertussis vaccine is a combination vaccine that protects against these three diseases:
Diphtheria usually causes inflammation of the throat and mucous membranes of the mouth. However, the bacteria that cause diphtheria produce a toxin that can damage the heart, kidneys, and nervous system. Diphtheria was once a leading cause of death in children.
Tetanus (lockjaw) causes severe muscle spasms, which result from a toxin produced by bacteria. The bacteria usually enter the body through a wound.
Pertussis (whooping cough) is a very contagious respiratory infection that is particularly dangerous to children younger than 2 years old and to people who have a weakened immune system.
For more information, see the Centers for Disease Control and Prevention's (CDC) Tdap (Tetanus, Diphtheria, Pertussis) vaccine information statement.
(See also Overview of Immunization.)
The vaccine has two forms:
Tdap has lower doses of diphtheria and pertussis vaccine, indicated by the lower case d and p. The lower doses are adequate for adolescents and adults. There is also a vaccine that contains only the tetanus and diphtheria components (tetanus-diphtheria vaccine).
The diphtheria-tetanus-pertussis vaccine is given as an injection into a muscle. As a part of routine childhood vaccination, five injections of DTaP are given: typically at age 2 months, 4 months, 6 months, 15 to 18 months, and 4 to 6 years.
Because pertussis is becoming more common among adults, a booster with Tdap is recommended at age 11 to 12 years to be followed by a tetanus-diphtheria booster every 10 years.
Adults who missed the series of vaccinations given during childhood should get it as adults. If adults did not receive Tdap at age 11 to 12 years or are unsure about whether they were vaccinated, doctors give them one dose of Tdap.
Pregnant women are given a dose of Tdap during each pregnancy.
Certain conditions may affect whether and when people are vaccinated (see also CDC: Who Should NOT Get Vaccinated With These Vaccines?). If people have a temporary illness, doctors usually wait to give the vaccine until the illness resolves.
The injection site may become sore, swollen, and red. Serious side effects are rare. They include high fever, inconsolable crying, seizures, and a severe allergic reaction.
Serious side effects usually result from the pertussis part of the vaccine. If they occur, the vaccine that contains pertussis is not used again. Instead, the tetanus-diphtheria vaccine (which does not contain the pertussis component) is used to complete the vaccination series.
The DTaP or Tdap vaccine is not repeated if seizures or other signs of brain malfunction occur within 7 days after the vaccine is given.