Do I need a tetanus (Td) shot after a cat bite?

Tetanus Prophylaxis After Cat Bite

Yes, you need a tetanus shot after a cat bite if your last tetanus vaccination was 5 or more years ago. Cat bites are classified as contaminated, tetanus-prone wounds requiring appropriate prophylaxis based on your immunization history. 1, 2

Why Cat Bites Are High-Risk

• Cat bites are classified as "other wounds" (non-clean wounds) that may be contaminated with dirt, feces, soil, or saliva—similar to puncture wounds and avulsions. 2
• Cats are coprophagic (feces-eating) animals, which increases the potential risk of tetanus transmission through their bites and scratches. 2
• While rare, tetanus cases have been documented after cat scratches and bites, even in previously immunized patients. 3

Tetanus Prophylaxis Algorithm Based on Your Vaccination Status

If Your Last Tetanus Shot Was <5 Years Ago:

• No tetanus vaccine or tetanus immune globulin (TIG) is needed. 1, 2
• Proper wound care alone is sufficient. 4

If Your Last Tetanus Shot Was ≥5 Years Ago:

• You need a tetanus toxoid-containing vaccine (no TIG required). 1, 2
• For persons aged ≥11 years who have not previously received Tdap or whose Tdap history is unknown, Tdap is preferred over Td. 1
• For persons with documented previous Tdap vaccination, either Td or Tdap may be used. 2

If You Have Unknown or Incomplete Vaccination History (<3 Doses):

• You need both a tetanus toxoid-containing vaccine AND TIG (250 units intramuscularly). 1, 4
• These should be administered using separate syringes at different anatomical sites. 4
• You must complete the 3-dose primary series: first two doses at least 4 weeks apart, third dose 6-12 months after the second. 1

Special Populations

Pregnant Women:

• Tdap should be used regardless of prior Tdap history if tetanus prophylaxis is indicated. 1, 2

Immunocompromised Patients:

• Persons with HIV infection or severe immunodeficiency who have contaminated wounds should receive TIG regardless of their tetanus immunization history. 1, 2

History of Arthus Reaction:

• Patients with a history of severe Arthus hypersensitivity reaction following a previous tetanus toxoid-containing vaccine should not receive tetanus vaccine until >10 years after the most recent dose, regardless of wound condition. 2, 4

Critical Wound Management

• Thorough wound cleaning and debridement are essential first steps to remove debris that might harbor Clostridium tetani spores. 4
• Surgical debridement of necrotic tissue is necessary for wounds that might create anaerobic conditions favorable for bacterial growth. 4
• The vaccine provides protection against future injuries, not the current one, but should still be administered when indicated. 5

Common Pitfalls to Avoid

• Do not assume cat bites are "clean wounds"—they must be treated as contaminated wounds requiring appropriate tetanus prophylaxis. 2
• Do not delay wound care while waiting for vaccination records; if history is uncertain, treat as unvaccinated. 1
• Remember that complete primary vaccination is nearly 100% effective in preventing tetanus, and protective antibody levels develop rapidly after a booster dose. 1, 4
• Even with proper childhood immunization and a booster 5 years prior, tetanus can still occur if appropriate prophylaxis is not given after high-risk exposure. 6