Diphtheria immunization (vaccine)

Alternative names
Immunization - diphtheria; Vaccine - diphtheria

This is an immunization (vaccination) to protect against diptheria (a bacterial disease that affects the throat and can cause serious or fatal complications). See also immunizations - general overview.


There are three forms of diphtheria immunization described next. See also pertussis immunization (vaccine) and tetanus immunization (vaccine).

The DTaP vaccine is a “3-in-1” vaccine that protects against diphtheria, pertussis, and tetanus. It can be given to children less than 7 years old. It is given by injection, usually into the arm or the thigh.

The DT vaccine is a “2-in-1” vaccine that can be given to children less than 7 years old. It protects against diphtheria and tetanus. It is given by injection, usually into the arm or thigh.

The Td vaccine is the “adult” vaccine. It is a “2-in-1” vaccine that protects against tetanus and diphtheria. It contains a slightly different dose of diphtheria vaccine than the DT vaccine. It can be given to anyone older than 7 years old. The vaccine is injected, usually into the arm.

Diphtheria vaccination is one of the recommended childhood immunizations which should begin during infancy. Diphtheria immunization is generally required before a child can start school. Five doses of vaccine are recommended during childhood.

DTaP or DT immunization is usually a series of injections given to children at ages 2 months, 4 months, 6 months, and 15-18 months. A booster is given before starting school (age 4-6). DTaP is recommended unless there is a reason that the child should not receive the pertussis vaccine (such as allergic reaction), in which case the DT should be given.

After the initial series of immunizations, a booster of Td vaccine should be given at age 11-12 and every 10 years thereafter.

This vaccine is highly effective at preventing diphtheria - a serious disease. DTaP and DT vaccine can be safely given to infants.

DTaP may cause mild side effects (slight fever, mild crankiness, tenderness of the injection site for a few days).

DTaP may rarely cause the following more serious complications:

  • high fever (more than 105 degrees F) in 1 out of 16,000 children  
  • non-stop crying for 3 hours or more in 1 out of 1,000 children  
  • seizure in 1 out of 14,000 children

More severe problems occur extremely rarely. These include:

  • serious allergic reaction (less than 1 in 1,000,000 children)  
  • long-term seizures/brain damage (so rare that the association with the vaccine is questionable)

If the child is sick with something more serious than a mild cold, DTaP may be delayed until the child is better.

If the child has had any of the following after an earlier DTaP, consult with the health care provider before the child receives another injection of the vaccine:

  • seizures within 3-7 days after injection  
  • any serious brain problem within 7 days after injection  
  • worsening of seizures or other brain problem (at any time)  
  • mouth, throat, or face swelling (serious allergy) within a few hours after injection  
  • difficulty breathing (serious allergy) within a few hours after injection  
  • temperature of 105 degrees F or higher within 2 days after injection  
  • shock or collapse within 2 days after injection  
  • persistent, uncontrolled crying that lasts for more than 3 hours at a time within 2 days after injection

For 1 or 2 days after injection with DTaP (DTP), (or less often, the DT or Td vaccine) the child may experience:

  • fever  
  • soreness at the injection site  
  • swelling at the injection site  
  • redness at the injection site

Adults who receive the Td vaccine (particularly if received more often than every 10 years) may experience soreness and swelling at the injection site, lasting for 2 or 3 days.

Your health care provider may recommend measures to reduce normal postimmunization symptoms. Acetaminophen may be recommended to reduce fever and soreness.

Some providers recommend a dose be given just prior to the injection to help avert common, minor side effects. Warmth (such as a warm, damp cloth or a heating pad) may help reduce soreness. Frequently moving or using the arm or leg that has received the injection is recommended and often reduces the soreness.


  • you are uncertain whether diphtheria-containing immunization should be given (see delay or contraindications).  
  • complications or severe symptoms develop after diphtheria-containing immunization, including seizures; fever above 105 degrees F; difficulty breathing; or other signs of allergy, shock, or collapse; or uncontrolled crying that lasts for more than 3 hours at a time.  
  • other symptoms develop after diphtheria-containing immunization.  
  • there are other questions or concerns about diphtheria immunization.


Johns Hopkins patient information

Last revised: December 5, 2012
by David A. Scott, M.D.

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.