Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Diphtheria-Tetanus-Pertussis Vaccine


Margot L. Savoy

, MD, MPH, Lewis Katz School of Medicine at Temple University

Last full review/revision Jun 2021| Content last modified Jun 2021
Click here for the Professional Version

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.

The vaccine has two formulations:

  • DTaP (diphtheria-tetanus-pertussis) for children under 7 years

  • Tdap (tetanus-diphtheria-pertussis) for adolescents and adults

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 [Td] vaccine).


The DTaP 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.

DTaP is followed by one lifetime dose of a Tdap booster given at age 11 to 12 years and given to people 13 years or over who have never received Tdap or who are unsure about whether they received it. This dose is followed by a Td booster every 10 years.

Pregnant women are given a dose of Tdap during each pregnancy (preferably at 27 to 36 weeks gestation). After pregnancy, women who have never received Tdap are given a dose.

Certain conditions may affect whether and when people are vaccinated (see also Who Should NOT Get Vaccinated With These Vaccines? from the Centers for Disease Control and Prevention [CDC]). If people have a temporary illness, doctors usually wait to give the vaccine until the illness resolves.

Side Effects

The injection site may become sore, swollen, and red. Serious side effects are rare. They include high fever, inconsolable crying, brain problems, seizures, shock, 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 occur within 3 days after the vaccine is given or other signs of brain malfunction occur within 7 days after the vaccine is given.

More Information

The following are some English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
Others also read

Test your knowledge

Chickenpox is a highly contagious viral infection that tends to be fairly mild in most cases. Which of the following groups has the lowest risk of complications from chickenpox?
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest

Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID