The following table highlights key information for immunization providers. Please refer to the remainder of the Statement for details
Hepatitis B virus (HBV) causes liver infection. Although the majority of individuals will spontaneously clear the infection, the risk of becoming a chronic carrier in unvaccinated individuals varies with age at which the infection occurs: up to 95% of infants, 50% of children less than 5 years of age and 10% of adolescents and adults will develop chronic infection.
Infant and adolescent immunization programs have been successfully implemented in all Canadian provinces and territories since 1990s. Duration of protection following a completed primary schedule is believed to be long lasting and no routine booster doses are currently indicated for immunocompetent individuals.
This Statement addresses whether there is a need for HB re-immunization of adolescents who have received routine immunization in infancy, risk of HB infection in people with diabetes and timing of re-vaccination of people with immunocompromising conditions.
Although decline of antibody levels may be observed over time, long-term protection and prevention of chronic infection is dependent on the presence of T- and B-cell memory. Anamnestic response to a HB vaccine challenge dose is considered to be a reliable measure of preserved immunologic memory and a correlate of protection in previously immunized individuals.
The majority of acute cases occur in unimmunized household contacts of a HB carrier and in people 30 years of age and older who acquire infection through unprotected sexual activity, sharing injection drug equipment or procedures with percutaneous exposure.
Healthy, immunocompetent, individuals who received HB vaccine according to recommended schedules are considered to be immune to HB infection. Presence of anamnestic response in the majority of individuals vaccinated in infancy is indicative of long-term protection.