According to The CDC:
During 1998–2000, an average of 43 cases of tetanus was reported annually; the average annual incidence was 0.16 cases/million population. The highest average annual incidence of reported tetanus was among persons aged >60 years (0.35 cases/million population), persons of Hispanic ethnicity (0.37 cases/million population), and older adults known to have diabetes (0.70 cases/million population). Fifteen percent of the cases were among injection-drug users. The case-fatality ratio was 18% among 113 patients with known outcome; 75% of the deaths were among patients aged >60 years.
So, high-risk groups are:
ages 60 years and above
people of Hispanic ethnicity
older adults with diabetes
IV drug users.
Findings in Tetanus Surveillance further show that vaccinated children are being treated for tetanus:
(13%) of the 122 non-neonatal patients with supplemental data were reported to have received at least a primary series (i.e., three or more doses) of TT before onset of illness (Table_1), including two (40%) of the five non-neonatal patients aged less than 20 years. Three (60%) of the non-neonatal patients aged less than 20 years were unvaccinated because of their parents’ religious objections. The fourth case occurred in a boy aged 14 years who was bitten by a dog and who had received his last dose 2 years previously.
So, of the children under the age of 20 treated for tetanus, 40% were vaccinated. One within the last 2 years.
Tetanus Surveillance covering the years of 1998-2000 (released in 2003) demonstrate:
Eight of 50 patients (16%) with known vaccination history during 1998–2000 had received >3 doses of tetanus toxoid with the last dose <10 years before the onset of tetanus (Table 1). All eight patients had nonwork-related acute injuries; six did not seek medical care before the onset of tetanus, and three were aged <20 years.
In this case, 37.5% of the cases with supplemental data under the age of 20 years were fully vaccinated (ie. at least a primary series of 3 tetanus vaccines).
Interestingly, the tetanus vaccine has never been tested for efficacy.
Efficacy of the toxoid has never been studied in a vaccine trial. It can be inferred from protective antitoxin levels that a complete tetanus toxoid series has a clinical efficacy of virtually 100%…