Objective: To evaluate the effectiveness in older Australians of the current tetanus vaccination program.
Design: A cross-sectional survey of tetanus immunity (enzyme immunoassay of serum samples) in an older population in New South Wales. Self-reported history of tetanus vaccination was compared with serologically measured immunity.
Participants: 430 randomly selected adults, 49 years of age and older, from the Blue Mountains Eye Study population.
Results: Fifty-two per cent (95% confidence interval [CI], 47%-57%) of adults 49 years of age and older had protective levels of tetanus antitoxin ( > 0.15 IU/mL). There was a significant decline in the prevalence of immunity with increasing age (chi 2 for linear trend, P = 0.036), and women were less likely to be immune regardless of their age (Mantel-Haenszel weighted odds ratio, 0.65; CI, 0.43-0.92). Thirty-five per cent (95% CI, 31%-40%) of all participants reported that they had been vaccinated in the preceding 10 years. Although self-reported tetanus vaccination history was associated with tetanus immunity, it was neither sensitive nor specific as a test for immunity.
Conclusions: About half the adults 49 years of age and older in the Blue Mountains area of New South Wales do not have protective levels of tetanus antitoxin because of inadequate vaccination coverage in this age group. Vaccination history is not a reliable indicator of tetanus immunity and a system is needed for accurate recording of adult vaccination.