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Combining hepatitis A and B vaccination in children and adolescents
P Van Damme1, M Van der Wielen
1Center for the Evaluation of Vaccination, WHO Collaborating Centre, Department of Epidemiology and Social Medicine, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium. pierre.vandamme@ua.ac.be
Insights
A combined hepatitis A and B vaccine offers a simplified vaccination schedule, improving compliance and reducing costs. This dual vaccine provides comparable immune responses to separate vaccines, making it a viable option for widespread immunization programs.
Area of Science:
- Immunology
- Vaccinology
- Public Health
Background:
- Hepatitis A and B are significant global health concerns, with infection severity linked to age at initial exposure.
- Infant hepatitis B infection carries a 90% risk of chronicity, while delayed hepatitis A vaccination increases morbidity and mortality.
- Despite differing transmission routes, overlapping epidemiology supports combined vaccination strategies.
Purpose of the Study:
- To evaluate the efficacy and advantages of a combined hepatitis A and B vaccine.
- To assess the immune response and seroprotection rates of the combined vaccine compared to monovalent vaccines.
- To explore the potential of simplified vaccination schedules for combined hepatitis A and B vaccines.
Main Methods:
- Comparative analysis of immune responses elicited by combined versus monovalent hepatitis A and B vaccines.
- Evaluation of seroprotection rates and speed of response following different dosing schedules (three-dose and two-dose).
- Review of public health recommendations and country-level vaccination strategies for hepatitis A and B.
Main Results:
- The combined vaccine elicits immune responses comparable to monovalent vaccines.
- A three-dose schedule demonstrated robust anti-hepatitis A virus (HAV) and anti-hepatitis B sero-responses.
- The combined vaccine accelerated seroprotection for hepatitis B, with over 80% achieving protection within one month after two doses (0, 1, 6 months).
- A two-dose schedule (0, 6 months) of the adult formulation showed promising immunogenicity and safety in children and adolescents.
Conclusions:
- Combined hepatitis A and B vaccination offers advantages like fewer injections, improved compliance, and reduced costs.
- The combined vaccine is a viable alternative for infant and adolescent immunization, with potential for simplified schedules.
- Widespread adoption of combined vaccines can enhance public health outcomes by increasing vaccination coverage and reducing disease incidence.
Abstract:
Hepatitis A and B are common infections worldwide and their severity is related to the individual's age upon initial infection. Furthermore, when hepatitis B infection occurs in infants, the risk of becoming a chronic carrier is 90%. For hepatitis A, the lower incidence of disease arising from an improvement in living conditions leaves a greater number of children, adolescents and young adults susceptible to residual circulating virus. Consequently, initial infection occurs later in life when clinical illness is more frequent and the rate of morbidity and mortality higher. Although both viruses differ greatly, including their modes of transmission, the overlap in their epidemiology warrants the combination of hepatitis A and B vaccination. The immune response elicited by the combined hepatitis A and B vaccine following a three-dose schedule compares well with the anti-hepatitis A virus (HAV) and anti-hepatitis B sero-responses obtained with monovalent vaccines. In addition, it was shown that the seroprotection rate for anti-hepatitis B increased more rapidly with the administration of the combined vaccine, with values of more than 80% within 1 month after the first two doses (schedule, 0, 1 and 6 months). Currently, according to the World Health Organization recommendations, more than 116 countries are vaccinating their infants and/or adolescents against hepatitis B. Recently, several countries were considering or have decided to begin mass vaccination against HAV (more than fifteen states in the US, Spain (Catalonia), Italy (Puglia)). For these countries, the combination of hepatitis A and B antigens in one single vaccine offers the following advantages: fewer injections for protection against two infections, better compliance, lower implementation costs, and fewer missed vaccination opportunities. Further simplification of the schedule, by reducing the number of doses, would improve the compliance rate as well as being more convenient for the vaccinee. This should translate into a reduction in costs associated with vaccine administration. In some recent vaccine studies, the immunogenicity and safety profile of a two-dose schedule (0 and 6 months) of the adult formulation of the combined hepatitis A and B vaccine was investigated in children aged 1-11 years, as well as in adolescents aged 12-15 years. Current results indicate that this two-dose schedule of the adult formulation could be considered a viable alternative for immunization of children and adolescents.