How effective is Tetanus vaccine?
No randomized control studies on the efficacy of the tetanus toxoid have ever been completed. Data on what can be considered the minimal level of blood anti-tetanus antibodies believed to be protective against tetanus disease is scarce however, a tetanus antibody level of 0.01 IU/mL and above is considered indicative of protection against tetanus disease.1
The CDC reports that a single dose of tetanus toxoid will likely not protect a person from developing tetanus but that three tetanus toxoid vaccine doses should induce vaccine acquired blood antibody levels considered to be protective against tetanus disease in nearly all individuals. Vaccine acquired tetanus blood antibody levels, however, decrease with time and within 10 years, most individuals may only have blood antibody levels considered minimally protective against tetanus disease. As a result, the CDC recommends tetanus vaccination every 10 years, however, in the event that a serious wound occurs and the previous dose of tetanus toxoid vaccine is greater than 5 years earlier, a booster dose of tetanus toxoid vaccine is recommended.2
There are several published case studies reporting on the incidence of tetanus disease among vaccinated persons, including severe and fatal tetanus cases among persons found to have blood anti-tetanus antibodies considered to be well above the minimum level considered to be protective against tetanus.3 4 5 6 7 8 9
Neonatal tetanus cases have also been reported in newborns found to have significantly elevated tetanus blood antibody levels. In one study, seven newborns diagnosed with neonatal tetanus were found to have antibody levels between 4 and 13 times the minimally accepted level (0.01 IU/ml) considered to be protective against tetanus disease. The mothers of all but one infant had received a dose of tetanus toxoid vaccine (TT) during pregnancy. Two additional newborns diagnosed with neonatal tetanus, born to mothers who had received multiple doses of tetanus toxoid during pregnancy, were found to have antibody levels at 100 and 400 times the minimal protective level. Researchers hypothesized that the administration of the tetanus toxoid vaccine (TT) during pregnancy might produce tetanus disease by overwhelming the pre-existing tetanus anti-toxin levels and that multiple doses of tetanus toxoid vaccine administered during pregnancy could also result in an ineffective immune response.10
Between 2001 and 2008, there were a total of 233 reported cases of tetanus (average of 29 cases per year). Of the 197 cases where outcomes were known, 26 (13.2 percent) were fatal. Tetanus vaccination status was known in 92 out of 233 cases (39.5 percent). 55 individuals (59.3 percent) reported receiving at least one dose of a tetanus toxoid vaccine (TT), with 24 (26.1 percent) reported having received at least 4 or more tetanus toxoid vaccine doses. 11
Between 2009 and 2015, there were 197 cases and 2 deaths associated with tetanus disease. Tetanus vaccination status was reported on a total of 49 cases (25 percent). Of cases where vaccination status was reported, 10 cases of tetanus disease (20 percent) occurred in individuals reporting a history of receiving at least three doses of tetanus toxoid vaccine.12
The Adacel (Tdap) vaccine product insert reports that in clinical studies examining the concomitant administration of Adacel with the trivalent inactivated influenza vaccine, Fluzone, tetanus booster response rates were significantly lower in the group receiving the vaccines concurrently when compared to those who received the vaccines separately. In both groups, however, more than 98 percent of vaccine recipients were found to have blood immune levels considered to be protective against tetanus.13
IMPORTANT NOTE: NVIC encourages you to become fully informed about Tetanus and the Tetanus vaccine by reading all sections in the Table of Contents , which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.
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1 CDC Prevention of Pertussis, Tetanus, and Diphtheria with Vaccines in the United States: Recommendations of the Advisory Committee on Immunization Practices (ACIP) MMWR Apr. 27, 2018; 67(2);1–44
2 CDC Tetanus – Tetanus Toxoid Epidemiology and Prevention of Vaccine-Preventable Diseases (The Pink Book). 13th ed. 2015.
3 Vollman KE, Acquisto NM, Bodkin RP. A case of tetanus infection in an adult with a protective tetanus antibody level. Am J Emerg Med. 2014 Apr;32(4):392.e3-4
4 Pryor T, Onarecker C, Coniglione T. Elevated antitoxin titers in a man with generalized tetanus. J Fam Pract. 1997 Mar;44(3):299-303.
5 Passen EL, Andersen BR. Clinical tetanus despite a protective level of toxin-neutralizing antibody. JAMA. 1986 Mar 7;255(9):1171-3.
6 Crone NE, Reder AT. Severe tetanus in immunized patients with high anti-tetanus titers. Neurology. 1992 Apr;42(4):761-4.
7 Abrahamian FM, Pollack CV Jr, LoVecchio F et al. Fatal tetanus in a drug abuser with "protective" antitetanus antibodies. J Emerg Med. 2000 Feb;18(2):189-93.
8 Hahn BJ, Erogul M, Sinert R. et al. Case report of tetanus in an immunized, healthy adult and no point of entry. J Emerg Med. 2004 Oct;27(3):257-60.
9 Murphy KJ. Fatal tetanus with brain-stem involvement and myocarditis in an ex-serviceman. Med J Aust. 1970 Sep 19;2(12):542-4.
10 Maselle SY, Matre R, Mbise R, Hofstad T. Neonatal tetanus despite protective serum antitoxin concentration. FEMS Microbiol Immunol. 1991 Jun;3(3):171-5.
11 CDC Tetanus Surveillance --- United States, 2001—2008 MMWR Apr. 1, 2011; 60(12);365-369
12 CDC Surveillance Manual – Chapter 16 – Tetanus – Background Nov. 17, 2017
13 FDA Adacel Product Insert Jan. 11, 2019