Researchers call on ACIP to update tetanus schedule

A new study reveals that tetanus vaccinations may last longer than previously thought and that updating guidelines as such could save close to $300 million annually.

The report, titled “Durability of Vaccine-Induced Immunity Against Tetanus and Diphtheria Toxins: A Cross-sectional Analysis,” and published in Clinical Infectious Diseases, revealed that antibodies from tetanus and diphtheria vaccination can last up to 30 years and has led researchers to call for a change to immunization schedules.

Mark K. Slifka, PhD, of the Oregon National Primate Research Center at Oregon Health and Science University, said this report is just one of several lines of evidence indicating that it might be time to modify the adult booster vaccination schedule.

Tetanus and diphtheria are rare diseases in the U.S., with tetanus occurring at a rate of about 1 case per 10 million people, and just five diphtheria cases reported in the last 15 years. About 99% of U.S. adults under age 60 are protected against these diseases, Slifka said.

Routine annual vaccination against tetanus and diphtheria began in the mid-1940s. By the 1960s, increased rates of adverse events due to hyper-immunization were occurring and a shift was made in 1966 to a 10-year schedule, Slifka said. At that time, the science of vaccine-induced antibody responses were not well understood, but with today’s technology he said it appears as though the true duration of immunity has been greatly underestimated.

The study reviewed immunity levels of 546 adults, and 97% of that population was seropositive to tetanus and diphtheria. Antibody responses had an estimated half-life of 14 years for tetanus and 27 years for diphtheria, according to the study. Using this data, researchers concluded that 95% of the population would remain protected against both diseases for 30 years or more without additional booster vaccination.

Next: Updating standards

Incentive to update standards

The World Health Organization currently only recommends a single adult booster dose to be given at the time of first pregnancy or during military services, Slifka said. This approach has not been associated with any increased risk for contracting these diseases, and Slifka said researchers believe it’s reasonable to follow this example and move forward with an updated schedule. He estimated that based on the direct costs of the vaccine alone, not including clinical visit and administration costs, changing the vaccination schedule could result in $280 million in annual healthcare cost savings without sacrificing vaccine-mediated protection.

Slifka said researchers are in the process of contacting the Center for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices (ACIP) to determine if it would be willing to consider changing the adult vaccination schedule from once every 10 years to once every 30 years, noting that clinicians should continue to adhere to guidelines set out by CDC and ACIP in the interim.

“We hope that our data will provide incentive to update the U.S. adult vaccination schedule in order to provide the best balance of effective vaccine-mediated protection while simultaneously reducing the number of clinic visits, decreasing vaccine-associated adverse events and curbing unnecessary health care costs,” Slifka told Medical Economics. “Developing an age-based vaccination schedule instead of the current time-based schedule might further increase patient compliance and could be combined with other age-based vaccines such as immunization against shingles among the older population base.”