Tdap Interchangeable With Td for Most Vaccine Indications

By Will Boggs MD

February 04, 2020

NEW YORK (Reuters Health) - The tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine can be substituted for the tetanus and diphtheria toxoids (Td) vaccine in situations where only Td vaccine had been recommended previously, according to updated recommendations from the Advisory Committee on Immunization Practices (ACIP).

"Either Tdap or Td can now be used in situations where Td only was previously recommended, including the decennial Td booster, tetanus prophylaxis for wound management, and for additional required doses in the catch-up immunization schedule if a person has received at least 1 Tdap dose," Dr. Fiona P. Havers of the Centers for Disease Control and Prevention (CDC), in Atlanta, told Reuters Health by email.

Beginning in 2005, ACIP has recommended a single dose of Tdap for adolescents and adults, followed by booster doses of Td every 10 years or when indicated for wound management.

In early 2019, the U.S. Food and Drug Administration (FDA) approved a second Tdap dose if administered at least eight years after the first Tdap dose and for use for tetanus prophylaxis when indicated for wound management if at least five years have elapsed since the previous receipt of any tetanus toxoid-containing vaccine. ACIP later updated its recommendations to allow use of either Td or Tdap where previously only Td was recommended.

Dr. Havers and colleagues summarize these recommendations and offer guidance regarding the use of Tdap vaccines in a paper in Morbidity and Mortality Weekly Report.

In general, people aged 11-18 years should receive a single dose of Tdap, followed by one booster dose of either Td or Tdap every 10 years throughout life to provide continued protection against tetanus and diphtheria.

People aged 19 years and older who have never received a dose of Tdap should receive one dose of Tdap, followed by booster doses of either Td or Tdap every 10 years throughout life.

The recommendations for routine Tdap immunization during each pregnancy have not changed. Pregnant women should receive one dose of Tdap at 27-36 weeks' gestation, preferably during the earlier part of this period.

For wound management when more than five years have passed since the last vaccine dose, Td or Tdap is indicated, although Tdap should be used for persons who have not received Tdap or whose Tdap status is unknown or who are pregnant, according to the authors.

The report also includes recommendations for catch-up immunization, prevention of neonatal and obstetric tetanus, and inadvertent administration.

Providers should be aware that some of these recommendations represent off-label indications, based on age, pregnancy status, and specific vaccine brands, the authors note.

"Allowing either Tdap or Td to be used in situations where Td only was previously recommended increases provider point-of-care flexibility," they say.

SOURCE: Morbidity and Mortality Weekly Report, online January 24, 2020.