August 05, 2025
4 min read
Key takeaways:
- Successful childhood vaccine schedules have rendered tetanus and diphtheria boosters unneeded,
- The move would align recommendations with other childhood vaccine-preventable infections.
Ending adult booster shots for tetanus and diphtheria could save the United States $1 billion a year and eliminate vaccinations that may not be needed, researchers argued.
Mark K. Slifka, PhD, professor of microbiology and immunology at the Oregon Health and Science University School of Medicine, told Healio that he and his colleagues have been studying the durability of immunity from vaccines against tetanus and diphtheria for the last 2 decades, publishing several previous studies that support their hypothesis that adult boosters for them are not needed.
Because of the successful childhood vaccine schedule, the U.S. could eliminate unneeded tetanus and diphtheria shots for adults, saving billions of dollars per year. Image: Adobe Stock
“We ask that [the U.S.] consider revisiting the current guidelines for adult booster vaccinations,” Slifka said.
‘Rare’ diseases
The new study, published in Clinical Microbiology Reviews, tied together the previous research with new analyses and comparisons to 14 “highly successful childhood vaccines,” he said.
Currently, the CDC recommends a five-dose DTaP series for infants and young children to protect against diphtheria, tetanus and pertussis (whooping cough), with the doses recommended to be given at age 2 months, 4 months, 6 months, between 15 months and 18 months, and age 4 years and 6 years. The agency also recommends a Tdap booster, which also protects against all three infections, for adolescents aged between 11 and 12 years.
The CDC recommends that adults receive a booster dose of either the triple combination vaccine or one against diphtheria and tetanus every 10 years, because protection against the now-rare viruses wanes over time. A one-dose booster of Tdap is recommended by the CDC for women during pregnancy.
“The decennial schedule was adopted in 1968 [and] there is a lot of research that has been performed over the last 50 years that is relevant to this health policy,” Slifka said.
According to Slifka and colleagues, scientists developed vaccines against diphtheria and tetanus in the 1920s. Cases of diphtheria peaked in the U.S. at 206,939 in 1921 and then began to decline, with the rate of decline speeding up as universal childhood vaccination in the 1940s.
“Both the incidence of diphtheria and diphtheria-related mortality have declined exponentially since that time to become a rare disease that most clinicians have never seen first-hand,” the researchers wrote, noting that the CDC identified just 41 cases of respiratory diphtheria and four deaths from it between 1980 and 1995.
From 1996 to 2018, there were just 14 cases of diphtheria and one diphtheria death, the researchers reported. All five diphtheria deaths during the 40-year period from 1980 to 2018, according to the researchers, were among people who had not been vaccinated.
Additionally, the researchers reported that there were no clusters of diphtheria and no evidence of outbreaks from secondary transmission thanks to 95% primary vaccination of school-age children during the time period.
Similarly, after the introduction of childhood vaccination programs, the incidence of tetanus declined from 0.41 cases per 100,000 people in 1948 to 0.008 cases per 100,000 people in 2019 — equivalently lowering incidence to less than one case per 10 million people, according to the researchers.
They also noted that tetanus is unique among vaccine-preventable diseases because it is not transmitted from person to person and, in a highly vaccinated country such as the U.S., the majority of tetanus cases are in unvaccinated or undervaccinated people.
According to the researchers, between 1995 and 1997, roughly 75% of U.S. tetanus cases occurred among people who were not vaccinated or who had unknown vaccination status, and 13 of the 14 tetanus-related deaths during the 3-year period were among the same groups of people. Among people during those years who were vaccinated, there were no deaths.
Money for other things
Initially, Slifka and colleagues looked to compare U.S. vaccine policies with those of the United Kingdom, which also started a national childhood vaccination program in the 1940s but recommends a five-dose childhood vaccine schedule and no adult boosters. However, the U.K. also has a significantly smaller population, among other variables, than the U.S.
For a better comparison, the researchers replaced the U.S. with France, which has a similar population size as the U.K. (67 million vs. 66 million) and similar gender and age distributions, as well as a five-dose childhood vaccine series. Additionally, France, like the U.S., has an adult booster schedule. Both countries also have comparable vaccination coverage to the U.S. — ranging from 94% to 96%.
According to the study, both France and Germany have a low incidence of either infection, with less than one tetanus case per 4 million person-years (0.21 per million person-years in France vs. 0.12 per million person-years in the U.K.) and less than one diphtheria case per 16 million person-years (0.06 per million person-years in France vs. 0.03 per million person-years in the U.K.).
All three countries having relatively low incidences of diphtheria and tetanus is proof of “how incredibly successful our current childhood vaccination programs are and how important it is to continue promoting the importance of high childhood vaccination coverage — not just for tetanus and diphtheria, but for all childhood vaccines,” Slifka said.
Noting that the U.K. has “proven” that adult boosters for the two infections are not needed to protect the public from either of them, the authors also said that changing the vaccine schedule for diphtheria and tetanus would align the U.S. with WHO recommendations and other countries and save a large sum of money that could be used for other things.
“By shifting to a new policy of no longer recommending adult booster vaccinations, we are aligning tetanus and diphtheria with the rest of our childhood vaccines — measles, mumps, rubella, polio, etc. — that do not require adult booster vaccinations,” Slifka said. “We can do all these things while also saving up to $1 billion in annual health care costs — money that can be perhaps better spent in funding vaccine advocacy and education programs while reducing vaccine hesitancy and science denialism.”
References:
For more information:
Mark K. Slifka, PhD, can be contacted at slifkam@ohsu.edu.
Perspective
At the moment, and for the last decade, the recommended updated vaccine for adults actually protects against three diseases, not just two — tetanus, diphtheria and pertussis, or whooping cough.
You could make the argument that the long-standing recommendation to get a booster against tetanus and diphtheria every 10 years represents over-immunization. You can make that argument, and I am very friendly to that argument.
However, the vaccine that we’re using is also protecting against whooping cough, and protection against whooping cough wanes over 5 to 10 years. To keep the adult population optimally protected against whooping cough — which is a very, very nasty disease, even in people who have previously been immunized — you have to revaccinate more frequently. Every 10 years seems like a reasonable, practical way to keep up your whooping cough protection.
The driver of the booster recommendation is not tetanus or diphtheria — it’s the whooping cough component.
William Schaffner, MD
Healio | Infectious Disease News Editorial Board MemberProfessor, preventive medicine and infectious diseases Vanderbilt University Medical Center
Disclosures: Schaffner reports no relevant financial disclosures.
