A new study, recently reported in the New England Journal of Medicine, questions whether Americans really need booster shots so frequently.

The researchers examined 630 stored blood samples from 45 patients. They looked at each sample and analyzed the decay rate for antibodies from vaccines including measles, mumps, rubella, and tetanus. The findings showed surprisingly high levels of disease-resisting antibodies in the blood of patients administered vaccinations years earlier. Vaccines trigger antibody creation by giving patients a small dose of the virus that creates the disease.

The persistence of the antibodies suggests that current guidelines for booster shots for some common conditions could be revised, according to the study. For example, tetanus shots could be administered once approximately every 30 years instead of the current 10-year recommendation. “If we can continue to improve our vaccines, someday we might be able to give one shot and give lifelong immunity,” said study author Mark K. Slifka, PhD.