Hepatitis B Virus (HBV)
What is hepatitis B?
Hepatitis means the inflammation of the liver and hepatitis B is a specific type of this infectious disease caused by the hepatitis B virus (HBV). The symptoms of HBV infection vary from person to person. Many people with HBV infection don’t develop any symptoms, especially when they are young, and most patients with chronic HBV infection don’t develop any symptoms until late stage. However, HBV can damage the hepatocyte (liver cell) and cause liver damage and cirrhosis (scarring of the liver). HBV can cause both acute and chronic infection (infections that can’t be resolved after six months). When patients are first infected with HBV they can develop flu like acute symptoms, including fatigue, fever, nausea, vomiting, …show more content…
body aches, dark urine, loss of appetite and abdominal pain. If infection persists, patients may develop more severe symptoms due to liver damage or liver failure. These symptoms include jaundice (yellowing of skin and eyes due to high bilirubin levels), ascites (accumulation of fluid in the peritoneal cavity) and confusion. HBV and HCV infections also account for the majority of cirrhosis and primary liver cancer globally with estimated 15-40% of patients developing liver failure, cirrhosis or liver cancer (6, 7).
Epidemiology of hepatitis B
Globally
HBV infection is a major international public health issue with estimated 248 million carriers (defined as positive for HBV surface antigen [HBsAg]) globally and 600,000 people die from HBV related liver diseases every year (1, 2).
The average HBV infection prevalence is estimated to be 3.6% and this varies significantly depending on geographic locations as shown in Figure 1 (2). Areas with higher HBV prevalence include West Africa, the Pacific Asia and China where most patients were infected during childhood (8). Regions with intermediate rate of prevalence are Central and Eastern Europe, Middle East and India. North America, Western and Northern Europe have very low HBV prevalence where most patients become infected in adulthood (9).
The burden of disease for hepatitis can be quantified in terms of Disability-Adjusted Life Years (DALYs) which is the sum of Years Lived with Disability (YLD) and Years of Life Lost (YLL). Global DALYs (per 100,000) for acute hepatitis B, liver cancer secondary to hepatitis B and cirrhosis of the liver secondary to hepatitis B are 68, 130 and 130 respectively (10). The economic burden of HBV infection is also significant especially during end stage liver disease, cirrhosis and liver cancer with an average medical cost of $40,512 over 2 years for a patient with chronic HBV infection
(11).
In Australia
Overall, Australia is a country with low prevalence (1 percent) of HBV infection (3). 207,000 people in Australia were estimated to be infected by HBV in 2012 and about half of those are undiagnosed (3, 12). The incidence of HBV infection in Australia has decreased steadily from 262 new diagnoses (1.2 per 100,000) in 2008 to 193 new diagnoses (0.8 per 100,000) in 2013 (3). HBV infection is not distributed equally and certain social groups have higher rate of infection, including people migrate from areas with higher infection rate, Aboriginal and Torres Strait Islander people, injecting drug users and men who have sex with men (12-16). Like most other countries with low infection rate, majority people with HBV infection in Australia become infected in their adulthood (more than 90 percent) and were born overseas (more than 70%) (3).
Hepatitis means the inflammation of the liver and hepatitis B is a specific type of this infectious disease caused by the hepatitis B virus (HBV). The symptoms of HBV infection vary from person to person. Many people with HBV infection don’t develop any symptoms, especially when they are young, and most patients with chronic HBV infection don’t develop any symptoms until late stage. However, HBV can damage the hepatocyte (liver cell) and cause liver damage and cirrhosis (scarring of the liver). HBV can cause both acute and chronic infection (infections that can’t be resolved after six months). When patients are first infected with HBV they can develop flu like acute symptoms, including fatigue, fever, nausea, vomiting, …show more content…
body aches, dark urine, loss of appetite and abdominal pain. If infection persists, patients may develop more severe symptoms due to liver damage or liver failure. These symptoms include jaundice (yellowing of skin and eyes due to high bilirubin levels), ascites (accumulation of fluid in the peritoneal cavity) and confusion. HBV and HCV infections also account for the majority of cirrhosis and primary liver cancer globally with estimated 15-40% of patients developing liver failure, cirrhosis or liver cancer (6, 7).
Epidemiology of hepatitis B
Globally
HBV infection is a major international public health issue with estimated 248 million carriers (defined as positive for HBV surface antigen [HBsAg]) globally and 600,000 people die from HBV related liver diseases every year (1, 2).
The average HBV infection prevalence is estimated to be 3.6% and this varies significantly depending on geographic locations as shown in Figure 1 (2). Areas with higher HBV prevalence include West Africa, the Pacific Asia and China where most patients were infected during childhood (8). Regions with intermediate rate of prevalence are Central and Eastern Europe, Middle East and India. North America, Western and Northern Europe have very low HBV prevalence where most patients become infected in adulthood (9).
The burden of disease for hepatitis can be quantified in terms of Disability-Adjusted Life Years (DALYs) which is the sum of Years Lived with Disability (YLD) and Years of Life Lost (YLL). Global DALYs (per 100,000) for acute hepatitis B, liver cancer secondary to hepatitis B and cirrhosis of the liver secondary to hepatitis B are 68, 130 and 130 respectively (10). The economic burden of HBV infection is also significant especially during end stage liver disease, cirrhosis and liver cancer with an average medical cost of $40,512 over 2 years for a patient with chronic HBV infection
(11).
In Australia
Overall, Australia is a country with low prevalence (1 percent) of HBV infection (3). 207,000 people in Australia were estimated to be infected by HBV in 2012 and about half of those are undiagnosed (3, 12). The incidence of HBV infection in Australia has decreased steadily from 262 new diagnoses (1.2 per 100,000) in 2008 to 193 new diagnoses (0.8 per 100,000) in 2013 (3). HBV infection is not distributed equally and certain social groups have higher rate of infection, including people migrate from areas with higher infection rate, Aboriginal and Torres Strait Islander people, injecting drug users and men who have sex with men (12-16). Like most other countries with low infection rate, majority people with HBV infection in Australia become infected in their adulthood (more than 90 percent) and were born overseas (more than 70%) (3).