Hepatitis B Fact Sheet
Bloodborne Pathogens
Section
Cause
- Hepatitis B Virus (HBV)
- DNA virus from the Hepadnaviridae family of viruses. Some
features in common with retroviruses.
- Hepatitis B surface antigen (HbsAg) discovered in 1965
- HbsAg also called Australian Antigen
- Four serotypes and seven genotypes of human hepatitis B (Hep
B)
Clinical Characteristics
Incubation
Period |
From 2 to 6
months |
Infectivity |
About 100 times more infective than
HIV |
Acute Illness |
About 90% of adults clear the virus
from their system after serious infection. |
Chronic Infection |
About 360 million people worldwide
have long-term infection (>=5%).
15 to 40% advance to liver damage and liver disease. |
Death from Chronic Liver Disease,
Disease from liver damage, and Cancer of the Liver |
15-25% risk,>1 million people per year worldwide
|
Changes in the genetic structure of Hepatitis B virus
(mutations) may be responsible for greater liver damage.
Signs and Symptoms
- Jaundice (yellowing of the skin and eyes), other general
symptoms such as tiredness, loss of appetite, joint pain, pain in
the stomach area, and feelings of sickness.
- Symptoms may not appear in all cases, and at least 30% of
seriously infected people may not show symptoms
Modes of Transmission
- Most infections can happen when body fluids including blood,
blood products of an infected person enters the body of a person
who is not protected against the virus. HBV has also been found in
semen.
- Infection routes include sexual contact with an infected person
and exposure to needlesticks and other 'sharps' which have
been contaminated with HBV (this includes people who inject
drugs).
- Can also be passed from mother to newborn infant at the time of
birth (vertical transmission).
Persons at Risk
Persons |
Level of
Risk |
Drug users who share needles or
other injecting equipment (works) |
High |
Those who 'snort'
drugs |
High |
Those who have unprotected sex with
multiple partners |
High |
Homosexual men |
Medium |
People from countries where the
virus is regularly found (Africa, Southeast Asia, the Middle East,
Southern and Western Pacific Islands, the Amazon Basin, Haiti and
the Dominican Republic). |
Medium |
Those who spend time in prison |
Medium |
Hemophiliacs |
Low |
Individuals who undergo
hemodialysis |
Low |
Health Care Workers (HCWs),
Emergency Services Workers |
Low |
Prevention
- Vaccines are available for the prevention of Hep B, and this is
the best way to protect yourself.
- Try to eliminate risky behaviours, such as unprotected sex and
injecting drugs.
- Pregnant women should be tested for Hep B. If they are
positive, there are simple measures which can protect their newborn
infants from infection.
- Avoid sharing personal items likely to become infected with
blood. These include toothbrushes and razors.
- Tattooing and body piercing are also possible transmission
pathways, so careful thought of the person performing these
procedures is recommended. Unless the equipment is cleaned and
sterilized effectively, the blood of an infected person may still
be present.
- HCWs and other people likely to be exposed to blood, blood
products, or other bodily fluids are advised to be vaccinated
against HBV.
Vaccine Information
- Vaccine options are available to protect against HBV.
- Recommended that all people who are in 'at risk' groups
ask their health care provider about vaccination.
- Most provinces in Canada have school-based immunization
programs, and it is recommended that all children aged 0-15 ask
about vaccination against HBV
Treatment
Two standard treatments for Hep B: interferon and lamivudine.
Interferon is used for short periods of time. If this treatment is
effective, the body will then suppress the virus on its own.
Lamivudine may be used in a similar manner, or may be used to
achieve long-term viral suppression. Newer treatments such as
adefovir are effective in lamivudine-resistant infections.
Canadian Data on the trends of HBV
- The incidence of Hep B was approximately 2.0 cases for every
100,000 persons in 2006 (Public Health Agency of Canada, Notifiable
Diseases On-Line)
- The prevalence is estimated to be 0.7-0.9%, and the
distribution of cases varies by ethnic origin, job and risk
group.
Reference: Bloodborne Pathogens Section, Blood Safety
Surveillance and Health Care Acquired Infections Division, Health
Canada, 2003