About
Brief study summary
In partnership with the Navajo Nation and Alaska Native Tribal Health Consortium, we conducted a study to assess whether Vaxelis, a hexavalent combination vaccine, provides a similar protective antibody response against H. influenzae type b (Hib) after the first dose as PedvaxHIB (Hib PRP-OMP), which was the recommended vaccine against Hib in American Indian and Alaska Native (AI/AN) children.
Study background
Historically, American Indian and Alaska Native (AI/AN) children aged <5 years have experienced invasive H. influenzae type b (Hib) disease at a rate that is at least 5 times higher than the general U.S. population. In the pre-vaccine era, the incidence of Hib disease peaked earlier for AI/AN children at 4-5 months than general US children at 6-9 months. Studies performed in AI/AN children revealed that the Hib PRP-OMP vaccine induced a protective antibody response against Hib with the first dose, which is given at 2 months. Following introduction of a two-dose primary series and a booster dose, the rate of Hib disease decreased substantially among AI/AN children
Vaxelis is a licensed hexavalent combination vaccine that contains Hib PRP-OMP and five other antigens (Hepatitis B surface antigen, Diphtheria Toxoid, Tetanus Toxoid, Acellular Pertussis [DTaP], and Inactivated Polio Virus [IPV]). Vaxelis received FDA approval in 2018 and is now recommended by the CDC for use in US infants as part of the routine immunization schedule. The CDC did not provide a preferential recommendation for AI/AN infants because the level of protection provided after the first dose was not known.
What are we doing?
The main goal of the study was to compare the immune response in AI/AN infants to these two licensed and recommended Hib vaccines: Vaxelis and PedvaxHIB. The study enrolled 333 AI/AN infants on the Navajo Nation and in Alaska from January 2022 to April 2023.
Following parental informed consent, infants in the study received either Vaxelis or PedvaxHIB along with the other routinely recommended childhood vaccines at 2, 4, and 6 months of age. Blood samples were collected four times to measure antibody levels against Hib. Participants were followed for approximately 5 months. Being in the study did not affect the routine clinical care the participant received. All information about participants is kept confidential.
How this will help improve health in your community?
After the first dose, levels of antibodies (germ-fighters) in children who received Vaxelis were very similar to the levels of antibodies in children who received PedvaxHIB. Based on these results, both vaccines provide strong protection early in life.
The results of the HibVax study were presented to the CDC’s Advisory Committee on Immunization Practices (ACIP). The ACIP voted unanimously to add Vaxelis to the list of preferentially recommended vaccines for AI/AN infants. Vaxelis was then added to the IHS formulary and made available for use. Since Vaxelis is a combination vaccine, infants who receive Vaxelis require fewer injections to complete their pediatric vaccine schedule.
Principal Investigator/Program Coordinator information
Laura Hammitt lhammitt@jhu.edu
Bianca Jackson bianca.jackson@jhu.edu
Additional Information
Learn more about the study on clinicaltrials.gov. Study results were published in the journal, Pediatrics in October 2024. The full text of the paper can be found here.
This research was supported in part by a research grant from Investigator-Initiated Studies Program of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co, Inc Rahway, New Jersey, acting on behalf of a joint venture with Sanofi Pasteur, Inc, Swiftwater, Pennsylvania, known as MSP Vaccine Company. The funder supplied the Vaxelis and PedvaxHIB vaccines administered in the study, and otherwise had no role in the design or conduct of this study.
