A DPT immunization is a combined vaccine to protect against three diseases: diphtheria, tetanus, and pertussis.

Diphtheria spreads when germs pass from an infected person to the nose or throat of others. It can lead to breathing problems, heart failure, paralysis, and death.

Tetanus is caused by a germ that enters the body through a cut or wound. It can lead to locking of the jaw joints and death.

Pertussis is a bacterial infection that is easy to catch. It causes severe coughing and gagging with little or no fever. The coughing may end in vomiting or cause a "whoop" sound when the person tries to breathe in.

When the full DPT vaccine series is given, it protects most children. It also makes these diseases milder for those who do catch them.

Who is a candidate for the procedure?

DPT is one of the recommended childhood vaccines. It is required in most states.

How is the procedure performed?

The DPT vaccine is a shot that is given in the thigh or arm. A child needs five DPT shots for full protection. The first shot should be given at 2 months of age. The second and third shots are given within the child's first year. The fourth shot is given at least 6 months after the third shot. Most children get the fourth shot at about age 15 to 18 months. The fifth shot, or booster, is given when the child is about to enter school. In most states, a child must have another DPT vaccine before starting school, at about age 4 to 6. A shot of Td vaccine, which is the adult version, should be given about 5 years later at age 14 to 16. Additional booster shots are advised every 10 years after that for life.