The CDC’s Advisory Committee on Immunization Practices have updated vaccine recommendations to allow interchangeable use of Tdap and Td in some cases.
The US Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices (ACIP) previously recommended a single dose of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine followed by decennial booster doses of tetanus and diphtheria toxoids vaccine (Td). However, new recommendations allow either Tdap or Td to be used in some situations, increasing flexibility for providers
A summary of the new recommendations was included in the latest Morbidity and Mortality Weekly Report.
Either Td or Tdap can now be used for the decennial Td booster, tetanus prophylaxis in wound management, and for additional required doses in the catch-up immunization schedule among individuals who have received at least 1 Tdap dose.
The decision was made based on evidence reviewed by the ACIP Pertussis Vaccines Work Group. The recommendations were based on clinical trials published from January 2013-June 2019 which evaluated Tdap vaccination in adolescents and adults who had previously received the vaccine.
Data from commercial insurance claims and public sector orders, as well as unpublished CDC data, were also used to assess the safety and benefit of using Tdap and Td interchangeably.
In the clinical trials, 2 studies showed no increased risk of adverse events in adults who received Tdap compared to those who received Td 10 years after their initial Tdap dose.
Another trial found more frequent mild adverse events such as injection site pain or fatigue in a Tdap group. However, a retrospective study of around 69,000 adolescents and adults featured no statistically significant increase in medical visits for limb swelling, cellulitis, pain in limb, seizure, paralytic syndromes, cranial nerve disorders, encephalopathy, encephalitis, or meningitis among people who received a follow-up dose of Tdap compared with those who received Td.
It was also determined through analysis of 2019 commercial insurance claims that Tdap claims are already 12 times higher than Td claims in adults, suggesting in practical terms that Tdap was widely used in place of Td by clinicians in the United States with acceptability to patients and providers.
After reviewing the data, all 14 members of the committee voted in favor of the new recommendations. It was not recommended that Tdap be considered preferential to Td, due to issues such as cost, but use of either vaccine is now allowed by recommendations in many cases.
People aged 11 to 18 years should receive a single dose of Tdap as well as a booster dose of either Td or Tdap every 10 years throughout life. Individuals aged 19 years or older who have not received a dose of Tdap should receive 1 dose of Tdap. For continued protection, either Td or Tdap can then be administered every 10 years throughout life.
No changes have been made to recommendations for routine Tdap immunization for pregnant women. Pregnant women should receive a dose of Tdap during each pregnancy, regardless of vaccine history. It is currently recommended that Tdap be administered at 27-36 weeks gestation, and preferably during the earlier part of that period.
In wound management cases, Tdap is preferred for people who have not previously received Tdap or whose vaccine history is unknown. For pregnant women, Tdap should be used. Among people who are not pregnant who have a history of Tdap vaccination, however, either Td or Tdap may be used.
“ACIP will continue to review data on Td and Tdap as they become available, examine the necessity and frequency of booster doses for protection against tetanus and diphtheria, and consider any needed policy changes,” the authors wrote.