According to the February 7, 2020, issue of the Morbidity and Mortality Weekly Report from the Centers for Disease Control and Prevention (CDC), a hexavalent vaccine that includes diphtheria and tetanus toxoids and acellular pertussis (DTaP) adsorbed, inactivated poliovirus (IPV), Haemophilus influenzae type b (Hib) conjugate (meningococcal protein conjugate), and hepatitis B (HepB) (recombinant)—DTaP-IPV-Hib-HepB—has been included in the federal Vaccines for Children program after a unanimous vote by the Advisory Committee on Immunization Practices (ACIP).1
The ACIP looked at 6 Phase III studies that evaluated the safety and immunogenicity of DTaP-IPV-Hib-HepB, which included 2 noninferiority studies that enrolled more than 4200 children using the US immunization schedule of 2, 4, and 6 months. Immunologic responses were assessed following the third dose of the vaccine. The studies found that overall the measured antibodies were noninferior to licensed comparator vaccines, with 1 exception for a pertussis antigen. However, noninferiority criteria was met by all pertussis antigens when using the second measured endpoint of the percentage that had met a prespecified vaccine response.
The safety profile was found to be consistent with licensed component vaccines. The investigators did find a higher rate of fever in recipients of the hexavalent vaccine when compared with those who had been given the pentavalent (DTaP-IPV/Hib) vaccine (47.1%-47.4% vs 33.2%-34.4%, respectively). Fever-related medical events such as febrile seizures occurred at similar rates in both groups.
Guidance for use
The vaccine is indicated for use at ages 2, 4, and 6 months. For the prevention of diphtheria, tetanus, and pertussis, the hexavalent vaccine can be used for the first 3 doses, when DTaP would be administered, but it should be used for the booster shots at ages 15 to 18 months and 4 to 6 years. If the hexavalent vaccine is given for either booster, there is no need to administer a dose of another vaccine with DTaP, if proper spacing of previous doses has been maintained.
In the event of an accelerated schedule to provide protection for pertussis, the series can start in infants aged 6 weeks with the second and third DTaP doses being given no earlier than 4 weeks after the preceding dose. As the recommended minimum age for the third dose of the hexavalent vaccine is 24 weeks, which is the minimum age for the HepB vaccine series, the hexavalent vaccine is not recommended for the third dose when on an accelerated schedule.
The combination vaccine can be used for the first 3 doses of the IPV series but is not indicated for the fourth dose. In the event the vaccine is accidentally given as the booster dose, a repeat dose of another vaccine with IPV is not necessary, as long as proper spacing of previous doses was maintained.
Haemophilus influenzae type b
When immunizing against Hib, 3 doses of Hib conjugate-containing vaccine would be needed to finish the primary vaccine, if the DTaP-IPV-Hib-HepB vaccine is administered for any dose. Following the completion of the primary series, the hexavalent vaccine should be used for booster doses. When proper spacing of previous doses has been maintained, a repeated dose of a Hib-containing vaccine does not need to be given when a dose of DTaP-IPV-Hib-HepB has inadvertently been given as a booster dose.
The vaccine is not licensed for the birth dose. It can be used for doses given at age 6 weeks or older to infants who have mothers who are hepatitis B surface-antigen (HBsAg) negative. It also can be given to infants aged 6 weeks and older of mothers who are either HBsAg positive or have unknown HBsAg status. If the third dose of DTaP-IPV-Hib-HepB is administered to an infant before they are aged 24 weeks or older, an additional dose of HepB vaccine should be given when the infant is aged at least 24 weeks, with proper spacing for previous doses.
For children on a catch-up schedule, the DTaP-IPV-Hib-HepB vaccine can be used in children aged younger than 5 years. The doses should not be given at intervals less than the minimum intervals provided in the General Best Practices Guidelines for Immunization (see Table 3-1 in “Timing and spacing of immunobiologics.”)
1. Oliver SE, Moore KL. Licensure of a diphtheria and tetanus toxoids and acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b conjugate, and hepatitis b vaccine, and guidance for use in infants. MMWR Morb Mortal Wkly Rep. 2020;69(5):136-139.