CDC Issues Guidance for Hexavalent Vaccine in Children

The US Centers for Disease Control and Prevention (CDC) issued guidance for a hexavalent combination vaccine for diphtheria, tetanus, pertussis, polio, hepatitis B, and Haemophilus influenzae type b (DTaP-IPV-Hib-HepB) in infants.

The US Food and Drug Administration approved the vaccine for children ages 6 weeks through 4 years in 2018. It is indicated for a 3-dose primary vaccination series in infants at ages 2, 4 and 6 months but won’t be available commercially in the United States before 2021.

The new vaccine promises to reduce the number of injections administered and improve vaccine coverage by combining component vaccines into a single vaccine, according to the guidance, published in the CDC’s Morbidity and Mortality Weekly Report.

Members of the Advisory Committee on Immunization Practices (ACIP) voted unanimously to include the new hexavalent vaccine in the federal Vaccines for Children program. The vaccine, known as Vaxelis, was developed by a joint partnership between Merck & Co. Inc. and Sanofi Pasteur known as MCM Vaccine Company.

“ACIP has previously stated that the use of a combination vaccine generally is preferred over separate injections of the equivalent component vaccines; considerations can include provider assessment, patient preference, and the potential for adverse events,” the authors of the report noted.

Between December 2018 and June 2019, the ACIP Combination Vaccines Work Group reviewed scientific evidence regarding the hexavalent vaccine, including 6 phase 3 studies evaluating safety, immunogenicity and noninferiority.

The vaccine was found to be noninferior to existing vaccines with the exception of 1 of 5 pertussis antigens, for which noninferiority was not met 1 month after completion of the 3-dose course. According to the new guidance, the DTaP-IPV-Hib-HepB vaccine can be used for the first 3 doses of the recommended DTaP vaccine, but should not be used for the fourth or fifth recommended dose.

Similarly, the DTaP-IPV-Hib-HepB also can be used for the first 3 doses of inactivated poliovirus, but isn’t recommended for the fourth dose. It also can be used as the primary series for prevention of invasive H influenzae type b disease, but shouldn’t be used for booster doses. For the prevention of hepatitis B, the hexavalent vaccine shouldn’t be used for the recommended dose at birth, but can be used for doses at or after 6 weeks.

The authors of the report also noted that more data is needed regarding H influenzae antibody response after the first dose of DTaP-IPV-Hib-HepB among American Indian/Alaska Native infants, for whom H influenzae meningitis has peaked at a younger age than other groups. At this time the hexavalent vaccine doesn’t have a preferential recommendation for American Indian/Alaska Native infants.

Improving vaccines for children is key as vaccine resistance continues to be a challenge for health workers. From the 2018-19 school year, the number of children included in vaccine exemptions increased for the third consecutive year. A recent study found that vaccine-preventable diseases correlated with legislative activity that restricted or expanded the ability to exempt children from school-entry vaccine requirements.