DTaP is a vaccine that protects children from three serious infectious diseases caused by bacteria: diphtheria (D), tetanus (T), and pertussis (aP).

Diphtheria is caused by the bacterium Corynebacterium diphtheriae. Toxins produced by this bacterium can make it difficult to breathe and swallow, and can also damage other organs such as the kidneys and heart.

Tetanus is caused by the bacterium Clostridium tetani, which lives in the soil, and can enter the body through cuts and burns. Toxins produced by the bacterium cause serious muscle spasms, which can affect breathing and heart function.

Pertussis, or whooping cough, is caused by the bacterium Bordetella pertussis, and is very contagious. Infants and children with pertussis cough uncontrollably and struggle to breathe.

There are two other vaccines that protect against these infectious diseases — the Tdap vaccine and the DTP vaccine.


The Tdap vaccine contains lower quantities of the diphtheria and pertussis components than the DTaP vaccine. The lower-case letters “d” and “p” in the vaccine name indicate this.

The Tdap vaccine is received in one dose. It’s recommended for the following groups:

  • people 11 years and older who’ve not yet received the Tdap vaccine
  • pregnant women in their third trimester
  • adults who are going to be around infants younger than 12 months old


The DTP, or DTwP, vaccine contains preparations of the entire B. pertussis bacterium (wP). These vaccines were associated with various adverse side effects, including:

  • redness or swelling at the site of injection
  • fever
  • agitation or irritability

Because of these side effects, vaccines with a purified B. pertussis component were developed (aP). This is what’s used in the DTaP and Tdap vaccines. Adverse reactions for these vaccines are less frequent than those for DTP, which is no longer available in the United States.

The DTaP vaccine is given in five doses. Children should receive their first dose at 2 months old.

The four remaining doses of DTaP (boosters) should be given at the following ages:

  • 4 months
  • 6 months
  • between 15 and 18 months
  • between 4 and 6 years old

The common side effects of DTaP vaccination include:

  • redness or swelling at the site of injection
  • tenderness at the injection site
  • fever
  • irritability or fussiness
  • tiredness
  • loss of appetite

You can help to relieve pain or fever following DTaP immunization by giving your child acetaminophen or ibuprofen, but be sure to check with your child’s doctor to find out the appropriate dose.

You can also apply a warm, damp cloth to the injection site to help ease soreness.

Call your child’s doctor if your child experiences any of the following after DTaP immunization:

  • fever over 105°F (40.5°C)
  • uncontrolled crying for three or more hours
  • seizures
  • signs of a severe allergic reaction, which can include hives, difficulty breathing, and swelling of the face or throat

In some cases, a child either shouldn’t receive the DTaP vaccine or should wait to receive it. You should let your doctor know if your child has had:

  • a serious reaction following a previous dose of DTaP, which can include seizures, or severe pain or swelling
  • any nervous system problems, including history of seizures
  • an immune system disorder called Guillain-Barré syndrome

Your doctor may decide to postpone vaccination until another visit or to give your child an alternative vaccine that contains only a diphtheria and tetanus component (DT vaccine).

Your child can still receive their DTaP vaccine if they have a mild illness, such as a cold. However, if your child has a moderate or severe illness, immunization should be postponed until they have recovered.

The DTaP vaccine is only for use in infants and young children. Pregnant women shouldn’t receive the DTaP vaccine.

However, the CDC recommends that pregnant women receive the Tdap vaccine in the third trimester of each pregnancy.

This is because infants don’t receive their first dose of DTaP until they’re 2 months old, leaving them vulnerable to catching potentially serious diseases like pertussis during their first two months.

Women who receive the Tdap vaccine during their third trimester can pass antibodies to their unborn child. That can help protect the baby after birth.

The DTaP vaccine is given to infants and young children in five doses and protects against three infectious diseases: diphtheria, tetanus, and pertussis. Infants should receive their first dose at 2 months of age.

The Tdap vaccine protects against the same three diseases, and is typically given as a one-time booster to people ages 11 and older.

Women who are pregnant should also plan to receive a Tdap booster during the third trimester of pregnancy. This can help protect your child against diseases like pertussis in the period before their first DTaP vaccination.