![]() ![]() Additional information about HB testing is available at the Government of Canada webpage. ![]() Chronic carriers express HbsAg, and may have HBeAg and measurable viral DNA in blood. Some individuals with acute HB infection will become chronic carriers. ![]() Persons with anti-HBs and anti-HBc are not infectious. This includes those who are currently infected and those who were infected in the past but have cleared the virus. In addition, antibody to HB core antigen (anti-HBc) will appear in persons who have been exposed to the virus. The presence of anti-HBs confers long-term immunity. In severe acute HB infections, anti-HBs may be present simultaneously with HBsAg. In most cases, antibody to HBsAg (anti-HBs) appears after HBsAg has disappeared and the infection has resolved. Persons in the acute stage of HB are considered infectious. HBsAg can be detected in serum 30 to 60 days after exposure and persists until the infection resolves. Two antigens are important in evaluating people with HB infection and are markers of HB carriage: hepatitis B surface antigen (HBsAg), which is present in either acute or chronic infection with HB virus and hepatitis B envelope antigen (HBeAg), which typically is associated with higher viral loads, increased infectivity and more actively replicating virus. The incubation period is 45 to 180 days (average 60 to 90 days). Saliva is considered infectious in bite wounds with broken skin involving the inoculation of saliva, or when it is visibly tainted with blood. The risk of transfusion-related HB is extremely low in Canada and the USA because all blood and blood products are tested. Transmission of HB occurs through close contact with infectious bodily fluids, including through sharing of injection drug equipment (such as needles), sexual contact, and from mothers who are acute HB cases or carriers to their newborns. HB is transmitted through percutaneous or mucosal contact with infectious biological fluids. For additional information about HB virus, refer to the Government of Canada webpage. ![]() Hepatitis B (HB) virus is a deoxyribonucleic acid (DNA) virus of the Hepadnavirdiae family. Epidemiology Disease description Infectious agent Significant revisions included in this chapter are highlighted in the Table of Updates to the Canadian Immunization Guide. Infants born to infected mothers are at highest risk of becoming chronic HB carriers.Chronic infection may lead to serious liver disease. A person with acute HB can become a chronic HB carrier and remain infectious.With few exceptions, people with indications for both hepatitis A (HA) and HB vaccine should be immunized with combined HAHB vaccine.There are many different HB-containing vaccine schedules and dosages.susceptible household and sexual contacts of an acute case or chronic carrier of HB.susceptible persons potentially exposed to blood or bodily fluids containing HB virus.Post-exposure prophylaxis (PEP) should be offered to:.Pre-exposure HB immunization is recommended for high-risk groups.Routine HB immunization is recommended for all children.Reactions to HB vaccine are generally mild and transient and include: irritability, headache, fatigue, as well as pain and redness at the injection site.HB vaccine is 95% to 100% effective pre-exposure.Infants, young children and immunocompromised persons are at highest risk of becoming chronic HB carriers.Initial infection with HB may be asymptomatic in up to 50% of adults and 90% of children.A high proportion of HB carriers in Canada are immigrants from HB-endemic areas. In Canada, most acute cases of hepatitis B (HB) occur in unimmunized household contacts of HB carriers and people 25 years of age and older who acquire infection through unprotected sexual activity, sharing injection drug equipment, or procedures with percutaneous exposure.Key Information (Refer to text for details) Storage and Handling of Immunizing Agents.Table 4: Hepatitis B immunization recommendations for preterm infants weighing less than 2,000 grams, by maternal hepatitis B surface antigen (HBsAg) status.Figure 2: Management of individuals with percutaneous or mucosal exposure to an uninfected or low risk source.Figure 1: Management of individuals with percutaneous or mucosal exposure to an infected or high risk source.Table 3: Recommended doses and schedules for hepatitis-B containing vaccines.Table 2: Recommended recipients of hepatitis B vaccine for pre-exposure prevention.Immunogenicity, Efficacy and Effectiveness.Immunizing Agents Available for Use in Canada.Table 1: Current provincial and territorial schedules for HB immunization and year of program introduction. ![]()
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