Dramatic reduction in hepatitis B through school-based immunization without a routine infant program in a low...

Area of Science:

• Public Health
• Infectious Disease Epidemiology
• Vaccinology

Background:

• Quebec, Canada, a low-endemicity province, implemented a comprehensive Hepatitis B (HB) prevention strategy.
• This strategy included two decades of pre-adolescent school-based immunization, catch-up campaigns for individuals born since 1983, and prenatal screening for maternal HBsAg.
• The study aimed to assess the added benefit of routine infant HB immunization by analyzing notifiable disease reports from 1990-2013.

Purpose of the Study:

• To evaluate the impact of existing Hepatitis B (HB) prevention programs in Quebec.
• To estimate the potential additional benefit of introducing routine infant HB immunization.
• To analyze trends in HB incidence and chronic HB rates across different age groups.

Main Methods:

• Utilized the Quebec provincial registry of notifiable diseases to identify confirmed HB cases between 1990 and 2013.
• Retrieved clinical and demographic information from standard public health unit questionnaires used for HB case investigations.
• Analyzed incidence data for acute, chronic, and unspecified HB cases per 100,000 population.

Main Results:

• Acute HB incidence decreased by 97% (6.5 to 0.2 per 100,000) between 1990-2013, with zero incidence in children and young adults by 2013.
• Newly-reported chronic HB rates declined by 66% overall, with significant reductions in children (92%) and adolescents (83%).
• Most HB cases in individuals ≤19 years old were immigrants infected before arrival; 8 out of 9 acute cases in children ≤9 yoa were not preventable by infant immunization.

Conclusions:

• Two decades of school-based immunization and prenatal screening dramatically reduced the HB disease burden in Quebec.
• The primary age groups targeted by catch-up campaigns are now past childbearing age, suggesting diminishing returns for infant immunization.
• Existing prevention strategies have been highly successful, with the potential for further incremental benefit from infant immunization being limited.