BALTIMORE — In settings with good access to care and high immunization rates, asking patients if they've received a tetanus booster in the last 10 years is a fairly accurate way to determine if they need one, Dr. M. Hassan Murad and his associates said in a poster presentation at a conference on vaccine research sponsored by the National Foundation for Infectious Diseases.
Patients who answer “yes” are probably right and do not need readministration of the vaccine. But those who say either “no” or “I don't know” should receive a tetanus-diphtheria (Td) booster as long as there are no contraindications, said Dr. Murad of the division of preventive medicine at the Mayo Clinic, Rochester, Minn.
Although previous studies have demonstrated poor accuracy of patients' recall of their last Td booster, this has not been evaluated previously in settings where immunization rates are high and good documentation is available. In this study, 572 patients of an employee health clinic of a large health care organization were asked whether they had a Td booster in the last 10 years. Of those, 65.6% were able to answer either “yes” or “no.”
Comparison of their responses with their charts yielded high sensitivity (92.4%) and low specificity (26.5%). Accuracy of recall did not differ by age or gender, Dr. Murad and his associates reported.
The results from this study patient population are likely generalizable to those of other working-age adults of similar education level. “Since the results rely in significant part on human memory of a rare event—a once-every-10-years shot—they probably reflect useful information. … The general characteristics of our population are they were mostly working age, education generally high school graduate or greater, and nearly all have good access to routine office care. That is probably similar to many office practices around the country,” Dr. Murad said in a follow-up interview.
The advantage to conducting this study at the Mayo Clinic is that the institution keeps exceptionally good electronic immunization records of all employees, he noted. “In addition, we believe that our results are generalizable to the newer form of the vaccine [tetanus-diphtheria-acellular pertussis] since it is given at the same interval and in similar situations.”