Duration of Protection from Tetanus Immune Globulin (TIG)
Human tetanus immune globulin provides passive protection for approximately 4 weeks (28 days), which is substantially longer than the 7-10 days of protection offered by animal-derived antitoxin. 1, 2
Pharmacokinetics and Duration of Passive Immunity
Peak blood levels of IgG are reached approximately 2 days after intramuscular injection of TIG, with detectable passive antibody titers observed in all subjects by 24 hours post-injection 1
The half-life of IgG in individuals with normal IgG levels is approximately 23 days, which translates to a protection duration of roughly 4 weeks 1, 2
In clinical studies, passive antibody titers persisted through a 21-day study period in all subjects receiving hyperimmune immune globulin products manufactured by the same process 1
Clinical Implications for Wound Management
TIG provides immediate passive protection by neutralizing free tetanus exotoxin, making it the product of choice when passive immunization is needed 1
The standard prophylactic dose is 250 units IM, which should be administered at a separate anatomic site from tetanus toxoid using a separate syringe 3, 1
TIG is indicated only for patients with <3 documented tetanus toxoid doses or unknown vaccination history presenting with any wound, or for severely immunocompromised patients with contaminated wounds regardless of vaccination history 3, 4
Comparison with Active Immunization
Unlike passive protection from TIG, complete primary vaccination with tetanus toxoid provides nearly 100% protection lasting ≥10 years 3, 4, 2
Persons who have received at least 2 doses of tetanus toxoid develop antitoxin antibodies rapidly after a booster dose, though this response does not occur within the first 4 days 5
When both TIG and tetanus toxoid are administered together, there is no interference with the immune response to active immunization, allowing simultaneous initiation of passive protection and active immunity 3, 6
Critical Clinical Pearls
Human TIG is strongly preferred over equine antitoxin because it provides longer protection (4 weeks vs. 7-10 days) and causes fewer adverse reactions, with historical foreign protein reaction rates of 5-30% for animal-derived products 1, 2
Patients receiving TIG must complete a 3-dose primary tetanus vaccination series for long-term protection, as passive immunization does not confer lasting immunity 3
The 4-week protection window from TIG does not eliminate the need for proper wound cleaning and debridement, which remain critical components of tetanus prevention 3