Flu vaccines have been about 59%-67% effective at preventing outpatient medical visits in patients ages 6 months to 17 years during the 2023-’24 flu season, according to data from the Centers for Disease Control and Prevention (CDC).
In addition, vaccine effectiveness against hospitalization for this age group was 52%-61% against any influenza, according to data from four reporting networks in 22 U.S. states reviewed Wednesday by CDC’s Advisory Committee on Immunization Practices (ACIP).
ACIP members also voted to add the tetanus and diphtheria (Td) vaccine for use in some children under 7 years of age in the Vaccine for Children (VFC) program and update language regarding the tetanus, diphtheria and acellular pertussis (Tdap) booster to align with its recommendations.
Flu vaccine effectiveness
Pediatric vaccine effectiveness against influenza A was 46%-59% for outpatients and 46%-56% for inpatients. Pediatric vaccine effectiveness against influenza B was 64%-89% for outpatients.
So far this flu season, 91 pediatric flu-related deaths have been reported to the CDC. While flu activity remains high, the number of weekly flu hospitalizations has been decreasing since the first week of 2024.
ACIP members also reviewed flu vaccine effectiveness data from a small study in California, which included data on laboratory-confirmed influenza cases between October 2023 and January 2024.
Data show a 56% vaccine effectiveness rate for children 18 years and younger against influenza A and B. Pediatric vaccine effectiveness was lower for influenza A (52%) when compared to influenza B (79%) but still was considered protective.
“Current influenza vaccines provide protection against laboratory-confirmed influenza in persons 6 months of age and older,” said Sophie Zhu, Ph.D., epidemic intelligence service officer with the California Department of Public Health. “Vaccine effectiveness was higher for influenza B and younger persons, but vaccination still provided protection for all age groups against both influenza A and B.”
Td update
For children who develop a contraindication to pertussis-containing vaccines, the CDC previously recommended the pediatric diphtheria and tetanus toxoid (DT) vaccine instead of DTaP. With the sole manufacturer of DT vaccine discontinuing production, however, it no longer is available in the United States.
Therefore, the CDC updated its vaccination guidance in January to allow vaccine providers to administer Td for all recommended remaining doses in place of DTaP in young children with a contraindication to pertussis-containing vaccines. Td is licensed for those ages 7 years and older and contains a lower dose of diphtheria toxoid compared to DT.
ACIP members voted unanimously to add Td vaccine for use in the VFC program for children 7 years of age and younger for whom receipt of the pertussis component is contraindicated. It also updated language regarding the Tdap booster to align with ACIP recommendations.
MassBiologics has discontinued production of its Td vaccine, TdVax, and it is expected to remain available only through June. Sanofi, which manufactures the only other U.S.-licensed Td vaccine (Tenivac), is taking steps to increase supply. However, supplies of Tenivac are expected to be constrained this year.
“Based on the rarity of developing a contraindication to pertussis-containing vaccines, the temporarily constrained supply of Td vaccine is not anticipated to prevent providers from utilizing Td vaccine for the children in the VFC program for whom it’s indicated,” said Jeanne Santoli, M.D., M.P.H., of the CDC Immunization Services Division.
