Interchangeability of Tdap/DTaP vaccine among updates in new immunization schedule

In its annual update to the Child and Adolescent Immunization Schedule, federal health officials have made a number of changes, including significant updates to the recommendations for hepatitis A and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis adsorbed (Tdap) vaccination.¹

Andrew Kroger, MD, MPH, Actin Education Team Lead for the Immunization Services Division at the Centers for Disease Control and Prevention (CDC), says these 2 vaccines had the most significant changes in the 2020 update.

“Hepatitis A vaccine is now recommended for catch-up vaccination of all children through age 18 years-previously it was through age 2 years,” he says, adding that there are 2 new recommendations concerning the Tdap vaccine. “Previously, a one-time dose of Tdap was recommended for persons aged 7 years and older as protection from pertussis, and for continued tetanus protection follow-up doses could be Td. Now, for the follow-up doses, either Td or Tdap can be administered.”

Additionally, Kroger says, children aged between 7 and 10 years who received a Tdap dose were recommended to receive another dose at age 11 years due to the 11- to 12-year-old general recommendations. Now, children who received Tdap doses at age 10 years of can have that dose count toward the 11- to 12- year recommendation. No additional doses will be required, Kroger says.

These changes allow practitioners to simplify administrations without compromising safety, he points out.

“The changes allowing providers to substitute Tdap for Td are based on a safety record of multiple doses of Tdap-which has been recommended for pregnant women in each pregnancy since 2012-and feasibility issues because many practices only carry Tdap and do not carry Td,” Kroger says. “The recommendation for counting a dose of Tdap given at age 10 years simplifies situations where state law requires a dose of vaccine for fifth graders, many of whom are still 10 years old. This change means these children don’t need to be revaccinated at age 11 to 12 years.”

Additionally, the guidelines state that DTaP inadvertently administered after age 7 years may count as part of the catch-up series for the 7- to 9-year age group. Routine Tdap doses should then be given at age 11 to 12 years. For children aged 10 to 18 years, DTaP doses should be counted as the adolescent Tdap booster, according to the guideline.

For younger children, it was noted that the fifth dose of the DTaP vaccine isn’t necessary if the fourth dose was given at age 4 years or older, and if that dose was administered at least 6 months after the third dose.

Additional changes to vaccines

Other changes include that the Haemophilus influenzae type b (Hib) catch-up vaccine isn’t necessary for children aged older than 5 years who are not deemed as high risk, and clarification on when 1 or 2 doses of the seasonal influenza vaccine should be given-as well as when live attenuated vaccines should be avoided.

For the hepatitis B (HepB) vaccine, a special situations node was added addressing recommendations for revaccination, which generally is not recommended. Revaccination is only warranted in patients with special situations including children born to hepatitis B surface antigen–positive mothers, patients undergoing hemodialysis, and those who are immunocompromised, according to the guidelines.

The polio vaccine had some minor name and organizational changes within the guideline, but there was also clarification given on the types of vaccine that meet US recommendations. According to the updated guidelines, among oral polio vaccines only the trivalent oral poliovirus vaccine counts as valid toward vaccine requirements, noting further that only oral polio vaccine doses administered before April 1, 2016-but not on or after-should be counted toward this requirement.

Several updates also were made to meningococcal vaccines. For children who received the meningococcal ACWY (MenACWY) vaccine before age 10 years, the new table clarifies who is at increased risk and in need of booster doses. Clarification also was made to the meningococcal serogroup B vaccines, with booster guidance mirroring that of the MenACWY guidelines.

When asked about whether the guidelines authors considered challenges with implementation and adherence to the immunization schedule, Kroger says they did not.

“The schedule doesn’t attempt to highlight implementation issues, but we have attempted to make the schedule more inviting to read-and therefore simpler-by structuring the cover page in a step-by-step format, streamlining the language in the notes, and achieving uniformity of appearance with the adult schedule,” Kroger says.

The updated schedule reflects the recommendations of the Advisory Committee on Immunization Practices (ACIP) for each vaccine, he adds.

References:

1.Committee on Infectious Diseases. Recommended childhood and adolescent immunization schedule: United States, 2020. Pediatrics. 2020;145(3). pii: e20193995. doi: 10.1542/peds.2019-3995