Why is Tdap (Tetanus, diphtheria, and pertussis) vaccine administered after a dog bite?

From the Guidelines

A Tdap vaccine is recommended after a dog bite to prevent tetanus infection, especially if the wound is contaminated and the individual has not received a tetanus booster within the last 5 years. Tetanus bacteria, Clostridium tetani, can enter the body through wounds, including animal bites, and cause a serious, potentially fatal infection affecting the nervous system 1. According to the Advisory Committee on Immunization Practices (ACIP) recommendations, a booster dose of tetanus toxoid vaccine should be administered for dirty wounds if >5 years has elapsed since the last dose and for clean wounds, if >10 years 1.

Key Considerations

• The Tdap vaccine is preferred over Td if the former has not been previously given 1.
• For those with an unknown vaccination history or who haven't been vaccinated in the past 10 years, tetanus immunoglobulin may also be given alongside the vaccine for immediate protection 1.
• The standard adult Tdap dose is 0.5 mL administered as an intramuscular injection.
• Additional treatments for dog bites usually include:
  • Thorough wound cleaning
  • Possibly antibiotics like amoxicillin-clavulanate
  • Evaluation for rabies risk depending on the circumstances of the bite and the dog's vaccination status

Important Notes

• The benefits of regular tetanus toxoid boosters in adults who have had a primary series have been questioned, although its use in “dirty wounds” seems sensible 1.
• Persons who have not completed the vaccine series should do so 1.
• The decision to administer TIG should be based on the primary vaccination history for tetanus 1.

From the FDA Drug Label

Guide to Tetanus Prophylaxis in Wound Management(3 ) History of Tetanus Immunization (Doses)Clean, Minor WoundsAll Other Wounds* Td†TIG‡TdTIG Uncertain or less than 3YesNoYesYes 3 or more§No¶NoNo#No

The Tdap vaccine is administered after a dog bite because tetanus prophylaxis is necessary for wounds that are contaminated with dirt, feces, soil, and saliva, such as those resulting from animal bites.

• If the patient has an uncertain or incomplete tetanus immunization history, they should receive Tdap and tetanus immune globulin (TIG) for all other wounds, including dog bites.
• If the patient has received 3 or more doses of tetanus toxoid, but it has been more than 10 years since the last dose for clean, minor wounds or more than 5 years since the last dose for all other wounds, a booster dose of Td is recommended 2.
• Proper wound care is also essential in preventing tetanus infection.
• The use of tetanus immune globulin is adjunctive to proper wound care. 2

From the Research

Tdap Vaccination After a Dog Bite

• The primary reason for administering Tdap (tetanus, diphtheria, and acellular pertussis) vaccine after a dog bite is to prevent tetanus infection, as dog bites can be prone to tetanus [ 3 ].
• Tetanus is a potentially fatal condition caused by the bacterium Clostridium tetani, which can enter the body through wounds or cuts [ 4 ].
• The Tdap vaccine provides protection against tetanus, as well as diphtheria and pertussis, and is recommended for adults who have not received a tetanus toxoid-containing vaccine in the past 10 years [ 5 ].

Risk of Tetanus Infection

• Dog bites can be considered high-risk wounds for tetanus infection, especially if the wound is deep or dirty [ 3 ].
• The risk of tetanus infection is higher in individuals who have not received a tetanus toxoid-containing vaccine in the past 10 years or have an uncertain vaccination history [ 4 ].

Prevention and Treatment

• Prevention of tetanus infection is crucial, and Tdap vaccination is an effective way to prevent the disease [ 5 ].
• In addition to vaccination, proper wound care and cleaning can also help prevent tetanus infection [ 3 ].
• If an individual develops tetanus infection, treatment typically involves administration of tetanus immune globulin (TIG) and supportive care [ 4 ].