What Are Diphtheria, Tetanus, and Pertussis?

Diphtheria is an infection caused by bacteria that releases toxins in the body. It spreads easily and can be deadly. The infection and toxins causes a thick coating in the nose and throat. This coating can make it hard to breath.

Tetanus (also known as lockjaw) is caused by bacteria that enter through broken skin. The bacteria release a toxin in the body. It affects the nerves and leads to severe muscle spasms. It can be deadly when it affects the muscles needed for breathing.

Pertussis is also known as whooping cough. It is caused by bacteria that easily spread from person to person. It causes swelling in the airways. This leads to a distinct, severe cough and breathing problems.

What Is DTaP?

DTaP is a vaccine to protect against these three infections.

The vaccine has inactive forms of these bacteria. Inactive forms cannot cause an infection. Instead, they stimulate the body to make antitoxins and antibodies to fight future infections.

Who Should Get Vaccinated and When?

DTaP is given to young children. It is given over a series of five shots. The vaccine is given at ages:

  • 2 months
  • 4 months
  • 6 months
  • 15 to 18 months
  • 4 to 6 years

Other, similar vaccines that are approved for older children and adults are:

  • Tdap—Tdap is for children aged 11 to 12 years old. It may also be given to teens or adults who did not previously receive it. This vaccine protects against diphtheria, tetanus, and pertussis.
  • Td—This is generally used as a booster shot. It may be given every 10 years. It protects against tetanus and diphtheria.

What Are the Risks Associated With DTap?

Common side effects are:

  • Soreness or redness at the site of the injection
  • Fever
  • Lack of energy
  • Irritability
  • Lack of hunger
  • Vomiting

Less common, but more serious side effects are:

  • High fever
  • Crying for over three hours
  • Severe allergic reaction
  • Seizure

Acetaminophen is sometimes given for pain and fever after a vaccination. In infants, this may weaken the vaccine's effectiveness. It should only be given if advised by a child's care team.

Who Should Not Get Vaccinated?

Children should not receive the DTap vaccine if they have had:

  • A severe allergic reaction after a dose of DTap (very high fever, non-stop crying, seizure)
  • A severe allergic reaction to any of the components that make up the vaccine

Children who are sick may be advised to wait by their care team.

What Other Ways Can These Diseases Be Prevented Besides Vaccination?

Vaccination is the best way to prevent these infections. Other strategies are:

  • Staying away from people who are sick
  • Proper wound care

What Happens in the Event of an Outbreak?

In the event of an outbreak, all people who have not received the vaccine should receive it. Antibiotics may be advised for people in close contact with someone who is infected.


Healthy Children—American Academy of Pediatrics

Vaccines & Immunizations
Centers for Disease Control and Prevention


Diphtheria. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/diphtheria. Accessed September 3, 2021.

Diphtheria, tetanus, and pertussis (DTaP) VIS. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/vaccines/hcp/vis/vis-statements/dtap.html. Accessed September 3, 2021.

DTaP vaccine: What you need to know (VIS). Healthy Children—American Academy of Pediatrics website. Available at: https://www.healthychildren.org/English/safety-prevention/immunizations/Pages/Diphtheria-Tetanus-Pertussis-Vaccines-What-You-Need-to-Know.aspx. Accessed September 3, 2021.

Immunization schedules. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/vaccines/schedules/index.html. Accessed September 3, 2021.

Pertussis. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/pertussis. Accessed September 3, 2021.

Td (tetanus, diphtheria) VIS. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/vaccines/hcp/vis/vis-statements/td.html. Accessed September 3, 2021.

Tetanus. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/tetanus. Accessed September 3, 2021.

Last reviewed July 2021 by EBSCO Medical Review Board Kari Kuenn, MD  Last Updated: 9/3/2021