Tetanus-diphtheria vaccine

[Sarah]

The tetanus-diphtheria (Td) vaccine protects against toxins produced by the tetanus and diphtheria bacteria, not against the bacteria itself. There is also a combination vaccine that adds protection against pertussis (diphtheria-tetanus-pertussis vaccine).
Typically, the tetanus bacteria enter the body through a wound and begin to grow and produce the toxin. The toxin causes severe muscle spasms and can be fatal. Therefore, vaccination is particularly important.
Diphtheria usually causes inflammation of the throat and mucous membranes of the mouth. Also, the bacteria that cause diphtheria produce a toxin that can damage the heart, kidneys, and nervous system. Before routine vaccination became available, diphtheria was a leading cause of death in children.
For more information, see the Centers for Disease Control and Prevention

[Luis Fok]

A vaccine for tetanus alone is available, but the tetanus vaccine is typically combined with those for diphtheria and/or pertussis. The vaccine for diphtheria is available only in combination with other vaccines.
For more information, see DTaP/Tdap/Td Advisory Committee on Immunization Practices Vaccine Recommendations and Centers for Disease Control and Prevention (CDC): Diphtheria, Tetanus, and Pertussis Vaccination.
(See also Overview of Immunization.)