What is the recommended treatment with tetanus immunoglobulin (TIG) for a patient with a recent animal bite and unknown or outdated tetanus vaccination status?

Tetanus Immunoglobulin (TIG) for Animal Bites with Unknown/Outdated Vaccination

For a patient with an animal bite and unknown or outdated tetanus vaccination status, administer BOTH tetanus toxoid-containing vaccine (Tdap preferred) AND tetanus immunoglobulin (TIG) 250 units IM at separate anatomic sites if the patient has received fewer than 3 lifetime doses or has unknown/uncertain vaccination history. 1, 2

Immediate Assessment Algorithm

Step 1: Verify Vaccination History

• Treat patients with unknown or uncertain vaccination histories as having had zero previous tetanus toxoid doses 1, 2
• Patients with military service since 1941 can be considered to have received at least one dose, though completion of primary series cannot be assumed 2
• Do not confuse "outdated" (completed series but >5-10 years ago) with "incomplete" (never completed 3-dose primary series) 1

Step 2: Classify the Wound

• Animal bites are classified as contaminated, tetanus-prone wounds because they may be contaminated with dirt, soil, saliva, and create puncture wounds 3, 1
• This classification determines a critical 5-year interval (not 10-year) for booster administration 1

Treatment Protocol Based on Vaccination History

For Patients with <3 Doses or Unknown History:

• Administer BOTH:
  • Tetanus toxoid-containing vaccine (Tdap strongly preferred over Td) 1, 2
  • TIG 250 units IM at a separate anatomic site using a separate syringe 1, 2
• Complete the 3-dose primary vaccination series: second dose at ≥4 weeks, third dose at 6-12 months after the second dose 1

For Patients with ≥3 Documented Doses:

• If last dose was ≥5 years ago: Give tetanus toxoid-containing vaccine (Tdap preferred) WITHOUT TIG 1, 2
• If last dose was <5 years ago: No tetanus toxoid or TIG needed 1, 2

Critical Administration Details

TIG Administration

• Standard prophylactic dose: 250 units IM (universal dose for all ages, not weight-based) 1, 2
• Infiltrate as much as anatomically feasible into and around the wound; inject remaining volume IM at a site distant from vaccine 3
• Never administer TIG in the same syringe or same anatomical site as the vaccine 3, 1
• TIG can be administered up to day 7 after starting vaccination if not given initially; beyond day 7, it is not indicated as antibody response to vaccine is presumed 3

Vaccine Selection

• Tdap is strongly preferred over Td for adults ≥11 years who have not previously received Tdap or whose Tdap history is unknown 1
• This provides additional protection against pertussis in addition to tetanus and diphtheria 1
• For pregnant women requiring tetanus toxoid, use Tdap regardless of prior Tdap history 1

Essential Wound Management

• Immediate thorough washing with soap and water for 15 minutes markedly reduces bacterial and rabies infection risk 3, 4
• Consider povidone-iodine solution irrigation 3
• Proper wound cleansing alone without other prophylaxis markedly reduces tetanus likelihood in animal studies 3
• Infected wounds should not be closed; suturing should be avoided when possible 3

Special Populations Requiring TIG Regardless of Vaccination History

• Severely immunocompromised patients (HIV infection, severe immunodeficiency) with contaminated wounds should receive TIG regardless of tetanus immunization history 1
• Elderly patients (≥60 years) should be prioritized for TIG if supplies are limited, as 49-66% lack protective antibody levels 1
• Immigrants from regions outside North America/Europe are less likely to have adequate vaccination history and should be prioritized 1

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 1
• Do not administer tetanus boosters more frequently than recommended as this increases risk of Arthus-type hypersensitivity reactions 1
• Do not assume completion of primary series without documentation - even patients with some military service may not have completed the full series 2
• Failure to provide tetanus vaccination when needed could result in preventable illness - a 79-year-old woman with proper vaccination but no booster after >5 years developed severe generalized tetanus from an agricultural injury 5

Rabies Prophylaxis Consideration

• Rabies prophylaxis should be considered for all feral and wild animal bites and in geographic areas with high rabies prevalence 3
• Consult local health department about risks and benefits of rabies immunoglobulin (day 0) followed by rabies vaccine at a different site 3
• For domestic animal bites, observe the animal for 10 days for signs of rabies when available 1