|TOWARDS THE ERADICATION OF HEPATITIS B IN TAIWAN
A Discussion Paper
Dr. Suzanne Wait
Table of Contents
Executive Summary 5
I.Introduction: Hepatitis B in Taiwan 8
II.What is hepatitis B? 9
Who is at risk of becoming infected? 9
Natural history 9
A silent disease 10
Liver cancer 11
A significant economic burden 12
III.Managing hepatitis B disease: prevention, screening, monitoring and treatment 12
Vaccination: the most effective prevention 12
Targeted prevention of high-risk groups 13
IV.Challenges to containing hepatitis B in Taiwan 16
A huge success story... 16
...Yet challenges remain: 17
1.Need for greater awareness and education 18
2.Need to ensure continued success of the vaccination programme 18
3.Need to improve standards of care for the management of hepatitis B 19
4.Need to overcome geographic and social inequities in access to care 19
V.The way forward 20
Hou JL, Jafri W, Lai CL, et al. Practical difficulties in the management of hepatitis B in the Asia-Pacific region. J Gastroenterol Heptol 2004; 19(9): 958-69. 24
Viral hepatitides have long been important public health problems in humans. The etiologic agents were not identified, until around 1965 when Baruch S. Blumberg first found the relationship of Australia antigen and serum hepatitis. Further characterizations revealed the antigen to be the surface antigen of the hepatitis B virus. This epoch-making observation launched a new era in the diagnosis, prevention and treatment of hepatitis B. In about 15-20 years, the natural history of hepatitis B virus infection was elucidated, and more importantly, an effective vaccine against the infection became available. In the meantime, the routes of transmission were also made clear, rendering interruption of the transmission more specific and effective. The hepatitis B vaccine together with the effective means of interrupting the transmission routes contributed greatly to the control of hepatitis B virus infection. However, these measures can do very little to those who have already been chronically infected. Fortunately, specific therapies against chronic hepatitis B have started to appear about 10-15 years before and the treatments improved substantially in the last few years. Although far from perfect, now we do have some effective means to treat those who are chronically infected.
In Taiwan, acute and chronic liver diseases have been known to be rampant in as early as the beginning of the last century. Studies around 1975 showed an extreme high prevalence of chronic hepatitis B infection in the general population (15%-20%), and 80%-90% of the chronic liver diseases as well as hepatocellular carcinoma were caused by chronic infection with the hepatitis B virus. This important health problem, repeatedly addressed by the academia in Taiwan, finally caught the attention of the Government in the late 1970s, and a government-sponsored control program was finalized in 1981. Accordingly, a mass vaccination program against hepatitis B, primarily aiming at immunizing newborn infants, was launched on July 1, 1984. Twenty years after implementation of the program, the hepatitis B carrier rate in children covered by the program decreased 85%, from ~15% to <1%. Most importantly, the deadly sequela of hepatocellular carcinoma in the vaccinees was also found to decrease in parallel . This is the first time in history that a human cancer is prevented by vaccination. Despite the success, there are still some who were born after implementation of the program but were not prevented from chronic hepatitis B infection and hepatocellular carcinoma. Non-compliance to vaccination schedule, breakthrough infection and intrauterine infection are the causes of the failure.
At present, we have effective measures in immunizing the susceptibles, interrupting the routes of transmission and treating the chronically infected people. The time of considering elimination or even eradication of hepatitis B virus infection has come. This is especially true for countries where hepatitis B infection is not endemic. Nevertheless, with the admirable results achieved in the past, Taiwan should also start to think about elimination/eradication of hepatitis B in the country, even though it will certainly be much more difficult than in the non-endemic countries.
Dr Suzanne Wait has spent substantial efforts and time in exploring the possibility of eliminating/eradicating hepatitis B in Taiwan. She reviewed the epidemiology of hepatitis B, and analyzed the problems that remain to be tackled in Taiwan. With this essay as an important reference, I hope that Taiwan can take further steps towards the elimination or eradication of hepatitis B.
Ding-Shinn Chen, M. D.
Distinguished Chair Professor
Division of Gastroenterology and Hepatology
Department of Internal Medicine
National Taiwan University College of Medicine
Hepatitis Research Center
National Taiwan University Hospital
7 Chung-Shan South Road
April, 2010 Taipei 10002, TAIWAN
The Hepatitis B virus (HBV) is the most common cause of viral infection of the liver in the world. More than two billion people worldwide have been infected with HBV and seventy-five percent of all chronic HBV infections occur in Asia.
The virus is transmitted by contact with the blood or body fluids of an infected person. In Asia, the main mode of transmission is from an infected mother to her newborn infant (mother-to-infant transmission). Other modes of transmission are child-to-child contact within households where a family member is infected, contamination through the reuse of unsterilised needles and syringes and sexual transmission (homosexual and heterosexual).
The natural history of hepatitis B is complex, as it starts off as an acute infection that may evolve into chronic disease. Hepatitis B is often called a ‘silent disease’ because symptoms may remain absent for several years and they are difficult to identify as they are not specific to hepatitis. .
When chronic hepatitis B does develop, it can lead to serious and debilitating liver disease if left untreated, including liver cancer. Liver cancer is the leading cause of cancer in Taiwanese men and accounts for 21.8% of male cancer deaths. It is the second-leading cause of cancer in women and accounts for 14.2% of female cancer deaths.
Hepatitis B is a preventable disease. Taiwan was the first country in the world to introduce a population-wide vaccination programme against hepatitis B for all newborns in 1984. This programme has been extremely successful at reducing the prevalence and mortality associated with HBV in children. However, prevalence remains high in adults, with more than 90% of the population having been infected with HBV in the past. It is estimated that there are between 2.5 and 3 million carriers of HBV in Taiwan today.
For those infected with HBV, appropriate management has been shown to substantially reduce the risk of long-term liver damage, including cirrhosis and liver cancer. Proper management of hepatitis B requires a combination of:
Prevention: vaccination of newborns is the most effective means of preventing hepatitis B. Targeted prevention of groups at risk, accompanied by strong educational campaigns, is also important.
Screening of individuals at risk: Given the absence of symptoms in the early stages of hepatitis B, many individuals do not know that they are infected. Screening programmes are thus necessary to contain the risk of infection by allowing individuals who are HBV-positive to follow the right course of care for themselves and take appropriate measures to avoid infecting others.
Diagnosis and monitoring: Hepatitis B is under-diagnosed in Taiwan. Once diagnosis is ascertained, it is critical that individuals are monitored regularly to determine whether the disease has progressed and whether treatment should be initiated.
Treatment: There have been important advances in the development of antiviral therapies to treat patients with hepatitis B, as are reflected in recent clinical guidelines in Asia and around the world. Early treatment is critical to prevent the progression of liver disease.
Despite a successful vaccination campaign and the existence of management options for patients infected with HBV, hepatitis B remains under-diagnosed and under-treated in Taiwan. Thousands of deaths per year are still attributed to HBV today.
Thus complacency cannot be allowed to develop. Some of the remaining challenges to achieving the optimal containment, and eventual eradication, of hepatitis B in Taiwan include:
Need for greater awareness and education: Governments, including local agencies, must continue extensive screening programmes for hepatitis B and provide information to help the general population better understand the natural history of hepatitis B, the risks associated with being an HBV carrier and the importance of appropriate care. Efforts aimed at educating physicians are also critical as many practitioners lack the necessary knowledge of the best care to offer their patients.
Need to ensure continued success of the vaccination programme: Careful quality control and monitoring of the outcomes of the vaccination programme must remain a public health priority for its success to continue. Further research is also needed into the evolving epidemiology of HBV in Taiwan to ensure that vaccination programmes are not missing out on any new risk groups that may develop over time.
Need to overcome geographic and social inequities in access to care: Prevalence rates of HBV infection are higher in indigenous populations, in persons of lower socioeconomic status and in those living in remote areas. Moreover, most hepatologists and gastroenterologists are concentrated in the large urban centres and facilities for screening, diagnosis, monitoring and treatment may be very limited in remote areas.
Need to improve standards of care: As in many clinical areas, there is inconsistency in practice in the management of hepatitis B. In particular, confusion remains around when to initiate therapy and for how long. Careful monitoring during treatment, using the most meaningful tests and procedures available, is needed to continually evaluate the efficacy of treatment and to adapt treatment over time to prevent resistance to antivirals.
Need to remove financial barriers to care: Some of the screening tests, diagnostic tests, procedures (including liver biopsy) and antiviral therapies for hepatitis B do not benefit from full reimbursement in Taiwan. Thus individuals must often pay for them out-of-pocket. Costs may be prohibitive and prevent individuals from receiving an appropriate diagnosis, attending regular monitoring check-ups or seeking and continuing treatment. Removal of these financial barriers is essential if patients are to be offered optimal care.
In conclusion: Hepatitis B continues to represent a tremendous public health burden in Taiwan. Yet clinical experience has shown that effective screening, diagnosis, monitoring and treatment of individuals affected by HBV can prevent progression to severe liver disease in patients and thus lead to a significant reduction in the burden of illness posed by HBV on Taiwanese society. However, sufficient resources are needed to ensure that individuals affected by HBV receive the best care as early as possible. Concerted actions amongst all stakeholders – policy-makers, health professionals and patient representatives – are needed if we hope to achieve the elimination and eradication of hepatitis B from Taiwan in years to come.
Introduction: Hepatitis B in Taiwan
The Hepatitis B virus (HBV) is the most common cause of viral infection of the liver in the world. More than two billion people worldwide have been infected with HBV. Of these, more than 350 million suffer from chronic HBV infection (WHO, 2000). Chronic hepatitis B is more prevalent than HIV (50 million cases worldwide) as well as chronic hepatitis C (170 million cases worldwide).
Seventy-five percent of all chronic HBV infections occur in Asia. The prevalence in Taiwan is between 15-20% and more than 90% of the adult population has been infected with HBV in the past. It is estimated that there are between 2.5 and 3 million carriers of HBV in Taiwan today (Department of Health, 2008). HBV carriers are at risk of transmitting the virus to others. Also, they face an absolute lifetime risk of death from liver-related diseases, including cancer, of 15-20% (Lin and Kirschner, 2004). Indeed, hepatitis B is the main cause of liver cancer, which is in turn the most frequent cause of cancer in Taiwan (Chen D-S, 2007).
Taiwan was the first country in the world to introduce a population-wide vaccination programme against hepatitis B starting from all newborns in 1984. This programme has been extremely successful at reducing the prevalence and mortality associated with HBV in children. However, detectable virus remains a concern within the adult population and prevalence rates have not decreased in adults over the age of 18 since the onset of vaccination (Chen CH et al., 2007). Thus the burden posed by hepatitis B on society and on health care resources is likely to prevail for the considerable future (Mohamed et al. 2004).
For those infected with HBV, appropriate management has been shown to substantially reduce the risk of long-term liver damage, including cirrhosis and liver cancer. However, a large proportion of HBV-infected individuals do not access appropriate and timely diagnosis, monitoring or treatment in many countries of the world, including Taiwan. This is due to a number of factors, the most important of which is low awareness of the urgency to seek medical advice about hepatitis B in the general population. This is compounded by incomplete knowledge by treating physicians of the most appropriate management options for patients and financial barriers due to limited reimbursement of diagnostic and treatment alternatives.
Thus much remains to be done to minimise the burden of illness posed by hepatitis B on Taiwanese society.
The purpose of this document is to present an up-to-date summary of the main facts surrounding the prevalence, mortality, natural history, and management of hepatitis B in Taiwan, to raise public awareness and to provide a platform for discussion amongst patient representatives, leading scientific experts and policy-makers. It is hoped that this will assist all stakeholders to identify the key challenges and opportunities to be addressed if we are to move one step closer towards the elimination and eradication of hepatitis B infection in Taiwan.
What is hepatitis B?
The hepatitis B virus (HBV) is the most common of the different viruses (A, B, C, D and E) that cause hepatitis, which means inflammation of the liver (Lavanchy, 2005). Hepatitis B is transmitted by contact with the blood or body fluids of an infected person. Unlike hepatitis A or E, it cannot spread through contaminated food or water.
The virus survives out of the body for up to 7 days, thus the risk of infection upon exposure is very high. In fact, the virus is 100 times more infectious than HIV and 10 times more infectious than hepatitis C.
Who is at risk of becoming infected?
The main modes of transmission are:
Vertical – when an infected mother transmits it to her child at birth
Horizontal – health care workers exposed to sharp objects; sexual contact (heterosexual or homosexual) with infected individuals; shared contaminated needles amongst injection drug users; household contacts of chronically infected persons.
In Asia, the main route of transmission of HBV is from an infected mother to her newborn infant (m0ther-to-infant transmission). Other major modes of transmission are child-to-child contact within households where a family member is infected and contamination through the reuse of unsterilised needles and syringes in healthcare settings (Lavanchy, 2005).
The natural history of hepatitis B is complex, as it starts off as an acute infection that may evolve into chronic disease. Most cases of acute hepatitis B will resolve naturally without treatment. However, when chronic hepatitis B develops, it can lead to serious and debilitating liver disease if left untreated (see Figure 1 below).
The risk of developing chronic disease depends on the age at which one becomes infected. Around 90% of individuals who are infected as newborns will develop chronic HBV infection, whereas this risk is much lower if one is infected as a child younger than 5 years of age (25-30%) or as an adult (1-5%). For this reason, the main focus of vaccination programmes against HBV has been amongst newborns and children.
Figure 1: The natural history of hepatitis B
Adapted from Torresi et al, 2000 and Fattovich et al, 2003.