Diphtheria is a highly contagious infection. It can be life-threatening. It is caused by specific bacteria. The germ produces a toxin that can spread from the site of infection to other tissues in the body. Diphtheria usually affects the throat and nose. In serious cases, it may affect the nervous system and heart.

Diphtheria spreads easily from person to person by coughing or sneezing. People nearby breathe in the infected droplets. In rare cases, they come into direct contact with elements from an infected person’s mouth, nose, throat, or skin.

Because of a widespread immunization program, diphtheria is now rare in the United States.

The diphtheria vaccine is an inactivated toxin called a toxoid. There are different types of the vaccines to prevent diphtheria, including:

  • DTaP—given to children to protect against diphtheria, tetanus, and pertussis
  • DT—given to children who cannot receive the pertussis part of the DTaP vaccine
  • Tdap—given to children, adolescents, and adults to protect against tetanus, diphtheria, and pertussis
  • Td—given to adolescents and adults to protect against tetanus and diphtheria

The vaccine is injected into the muscle.