Should a Tdap (tetanus, diphtheria, and pertussis) vaccine booster be administered after a dog bite?

Tetanus Prophylaxis After Dog Bite

Yes, Tdap should be administered after a dog bite if it has been 5 or more years since the last tetanus-containing vaccine, as dog bites are classified as contaminated, tetanus-prone wounds requiring more aggressive prophylaxis than clean wounds. 1

Wound Classification

• Dog bites are classified as "non-clean wounds" that may be contaminated with dirt, saliva, or other materials, placing them in the category of tetanus-prone injuries. 1
• Animal bites carry a higher risk of tetanus infection due to potential contamination with Clostridium tetani spores from bacteria in saliva and environmental debris. 1
• This classification is critical because it determines the 5-year interval (not the routine 10-year interval) for booster administration. 1

Vaccination Algorithm Based on Immunization History

If Last Tetanus Vaccine Was <5 Years Ago

• No tetanus toxoid-containing vaccine or tetanus immune globulin (TIG) is needed. 1, 2
• The patient has adequate protection and additional vaccination would provide no benefit while potentially increasing adverse reactions. 3

If Last Tetanus Vaccine Was ≥5 Years Ago

• Administer tetanus toxoid-containing vaccine (Tdap or Td) WITHOUT TIG immediately. 1, 4
• For persons aged ≥11 years who have not previously received Tdap or have unknown Tdap history, Tdap is strongly preferred over Td to provide additional protection against pertussis. 1, 5
• For persons with documented previous Tdap vaccination, either Td or Tdap may be used. 1, 2

If Vaccination History Is Unknown or Incomplete (<3 Lifetime Doses)

• Administer BOTH tetanus toxoid-containing vaccine AND tetanus immune globulin (TIG) immediately. 1, 4
• Use separate syringes at different anatomical sites when administering both products. 2
• Begin a complete 3-dose vaccination series: first two doses at least 4 weeks apart, third dose 6-12 months after the second dose. 1, 4

Vaccine Selection Guidelines

Tdap is the preferred choice for most adult patients when tetanus prophylaxis is indicated after a dog bite, particularly for those who have not received Tdap previously or whose Tdap history is unknown. 1, 5 This recommendation exists because:

• Tdap provides protection against pertussis in addition to tetanus and diphtheria, addressing the ongoing pertussis epidemic. 5, 6
• The CDC Advisory Committee on Immunization Practices has recommended routine use of Tdap when tetanus prophylaxis is indicated since 2005 for adults <65 years and since 2012 for those ≥65 years. 5

Special Population Considerations

• Pregnant women requiring tetanus prophylaxis should receive Tdap regardless of prior Tdap history. 1, 2
• Children <7 years should receive DTaP. 2
• Children 7-10 years should receive Tdap. 2

Special Clinical Situations

Immunocompromised Patients

• Persons with HIV infection or severe immunodeficiency who have contaminated wounds should receive TIG regardless of their tetanus immunization history. 1, 4, 2
• This is because their immune response to vaccination may be inadequate. 4

History of Arthus Reaction

• Persons with a history of Arthus reaction following a previous tetanus toxoid-containing vaccine should not receive a tetanus toxoid-containing vaccine until >10 years after the most recent dose, even for tetanus prophylaxis as part of wound management. 3, 1
• Arthus reactions are characterized by severe pain, swelling, induration, edema, hemorrhage, and occasionally necrosis developing 4-12 hours after immunization. 3

Safety of Shortened Intervals

If urgent protection is needed and the last tetanus vaccine was given <5 years ago, Tdap can still be safely administered, though it is not routinely necessary. The evidence supporting this includes:

• A Canadian study of 7,001 students aged 7-19 years showed no increased severe local reactions when Tdap was administered at intervals as short as 18 months after prior tetanus-containing vaccines. 3
• No vaccine-related serious adverse events or Arthus reactions were reported at shortened intervals. 3, 7
• A study of 4,524 healthcare workers who received Tdap at intervals <2 years from prior Td showed comparable rates of adverse events to those with longer intervals. 3, 8

However, administering tetanus vaccines more frequently than recommended may increase local injection site reactions (erythema, swelling, pain), though these are generally mild and self-limited. 7, 8

Common Pitfalls to Avoid

• Do not confuse the 10-year routine booster interval with the 5-year interval for contaminated wounds - this is the most common error in tetanus prophylaxis. 4
• Do not withhold vaccination due to concerns about shortened intervals when clinically indicated for wound management - the benefits outweigh the risks of mild local reactions. 3
• Do not administer TIG to patients with a documented complete primary vaccination series (≥3 doses) - it is unnecessary and wasteful. 4
• Do not forget that proper wound care and debridement are critical in addition to vaccination for tetanus prevention. 2

Long-Term Protection

After receiving Tdap for wound management, subsequent booster doses of either Td or Tdap should be administered every 10 years throughout life to ensure continued protection against tetanus and diphtheria. 1, 4