Hepatitis B in childhood: An update for the paediatrician

Hepatitis B virus (HBV) infection may lead to acute or chronic hepatitis, cirrhosis and hepatocellular carcinoma. The incidence rate of paediatric hepatitis B is 0.2/100,000 to 1.8/100,000 in Canada. Hepatitis B virus infection is acquired largely through mother-to-infant (vertical) or community-based (horizontal) transmission in early childhood, whereas older children are susceptible to HBV infection through exposure to contaminated blood during intravenous drug use or through sexual transmission. Immigrants from endemic areas and some Native Canadian populations are also at a higher risk for HBV infection. Infection with HBV may manifest in three forms: acute self-limited hepatitis, chronic hepatitis or massive hepatic necrosis causing acute liver failure. The identification of HBV infection and the characterization of the disease relies on serological and virological tests. The course of chronic hepatitis B may be classified into three phases: an immunotolerant phase, an active phase and an inactive phase. Current treatment options include interferon-alpha and lamivudine for individuals with elevated serum alanine aminotransferase levels and markers of persistent viral replication. Children with chronic hepatitis B require regular monitoring and age-appropriate lifestyle counselling. Paediatricians are well-positioned to promote vaccination and encourage testing of those who are at risk for hepatitis B. With effective universal vaccination against hepatitis B, this infection could be essentially eliminated in Canada.     

Hepatitis A, B und C im Kindesalter

Hepatitis A, B, and C in children can raise diagnostic and therapeutic problems. Hepatitis A is a self limited infection with a fecal-oral transmission route. In children the clinical course is often asymptomatic or unspecific. The rate of icteric hepatitis A is growing with increasing age of the patient at time of infection. The prognosis is excellent in children. Active immunization against hepatitis A prevents infection. Hepatitis B is a more complex disease as chronic liver disease, aggressive hepatitis, and lack of therapeutic options are common problems in managing these patients. In children vertical transmission of the virus leads to a high rate of chronic disease. As therapeutic options are not very promising prevention of infection is a major tool. Active immunization is a safe and successful way to decrease the infection rate amongst populations. The prevalence of HCV infection in children is often underestimated. Children who have been treated with blood or blood products before 1991 are at major risk for Hepatitis C infection. As HCV in children is often mostly present without any symptoms or with minor symptoms, the disease often remains undiagnosed for a long period of time, especially these patients are at risk to distribute the disease. HCV infection in children seems to be more benign compared to adults, the rate of spontaneous elimination of the virus seems to be higher in children. Treatment of HCV infection in children should currently performed within clinical trials only.     

Hepatitis B virus infection

Hepatitis B virus (HBV) infection is a worldwide health problem and may cause acute, fulminant, chronic hepatitis, liver cirrhosis, or hepatocelullar carcinoma (HCC). Infection with HBV in infancy or early childhood may lead to a high rate of persistent infection (25-90%), while the rates are lower if infection occurs during adulthood (5-10%). In most endemic areas, infection occurs mainly during early childhood and mother-to-infant transmission accounts for approximately 50% of the chronic infection cases. Hepatitis B during pregnancy does not increase maternal mortality or morbidity or the risk of fetal complications. Approximately 90% of the infants of HBsAg carrier mothers with positive hepatitis B e-antigen (HBeAg) will become carriers if no immunoprophylaxis is given. Transplacental HBeAg may induce a specific non-responsiveness of helper T cells and HBcAg. Spontaneous HBeAg seroconversion to anti-HBe may develop with time but liver damage may occur during the process of the immune clearance of HBV and HBeAg. Mother-to-infant transmission of HBV from HBeAg negative but HBsAg positive mothers is the most important cause of acute or fulminant hepatitis B in infancy. Although antiviral agents are available to treat and avoid the complications of chronic hepatitis B, prevention of HBV infection is the best way for control. Screening for maternal HBsAg with/without HBeAg, followed by three to four doses of HBV vaccine in infancy and hepatitis B immunoglobulin (HBIG) within 24h of birth is the most effective way to prevent HBV infection. In areas with a low prevalence of HBV infection or with limited resources, omitting maternal screening but giving three doses of HBV vaccine universally in infancy can also produce good protective efficacy. The first universal HBV immunisation programme in the world was launched in Taiwan 22 years ago. HBV infection rates, chronicity rates, incidence of HCC and incidence of fulminant hepatitis in children have been effectively reduced.     

小儿庚型肝炎的探讨

为了探讨一种新型肝炎病毒，即庚型肝炎病毒（ｈｅｐａｔｉｔｉｓＧｖｉｒｕｓ，ＨＧＶ）在小儿中的感染特点，检测了３６例肝炎患儿及１６例健康体检儿童血清中ＨＧＶ－ＲＮＡ（套式逆转录ＰＣＲ法）。结果表明，３６例肝炎中有１１例ＨＧＶ感染者，其中６例合并慢性ＨＣＶ感染（３例接受过干扰素治疗），２例合并慢性ＨＢＶ感染，２例为慢性非Ａ－Ｅ肝炎，１例合并ＨＢＶ＋ＨＡＶ感染。１６例健康儿童均阴性。ＨＧＶ感染率在血制品输入者１０例中７例阳性，在未输入者２２例中３例阳性（两者比较，Ｐ＜０．０１），在血制品使用情况不明者２０例中１例阳性。提示输入血制品是小儿ＨＧＶ感染的主要途径，但不排除还有其他途径，感染者主要为慢性肝炎患儿，干扰素的疗效有待进一步研究     

Hepatitis B and C virus infections in Turkish children with haemophilia

We examined 41 Turkish children with haemophilia for evidence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections using the enzyme-linked immunosorbent assay (ELISA). Hepatitis B surface antigen was found to be positive in 11 patients (26. 8%) and HCV-specific antibody (anti-HCV) was detected in 10 (24. 4%) patients. There was a close relationship of the number of transfusions of blood plasma to the presence of HCV specific antibody, but not to the serum markers of HBV infection. In countries where HBV infection is commonly seen and problems in transfusion practice continue, as in Turkey, children with haemophilia are at greater risk for HBV and HCV infections.     

Hepatitis B and C virus infection in Polish children with malignancies

Infections by hepatotropic viruses belong to the most common complications of chemotherapy in children suffering from neoplastic diseases. The rate of hepatitis B virus (HBV) or hepatitis C virus (HCV) infection and the effectiveness of passive immunization against HBV were studied in 285 children; 148/285 with lymphoproliferative diseases and 137/285 with solid tumours. HBV infection was observed in 10.2% children receiving hepatitis B immune globulin as compared to 36.8% without passive immunization against HBV. Anti-HCV antibodies were similar in both groups amounting 38.7% and 32.6% respectively. Conclusion The results show that hepatitis B immune globulin administration is effective and that HCV might become the main cause of hepatitis among immunosuppressed patients in the future. Received: 13 December 1994 / Accepted: 18 October 1996     

The management of infants,children, and youth at risk for hepatitis C virus infection

Hepatitis C virus (HCV) infection affects 0.5% to 1.0% of the Canadian population. Most paediatric HCV infections are a consequence of vertical transmission or, among youth and young adults, the result of engaging in high-risk behaviours, such as injection drug use and unprotected sexual activity. It is now recommended that all infants, children, and youth with one or more risk factors be screened for HCV infection. Treating chronic HCV infection with direct-acting antivirals has been shown to achieve sustained virologic suppression in 97% to 100% of children as young as 3 years old. Paediatricians and family physicians have an important role in educating youth regarding HCV infection risks and prevention, and in advocating to government and public health authorities for comprehensive harm reduction interventions targeting at-risk youth, accessible treatments, and routine prenatal screening for HCV.     

Hepatitis C and G Virus infections in polytransfused children

The prevalence of hepatitis C virus (HCV) and a newly identified hepatitis G virus (HGV) and their clinical significance were studied in 42 polytransfused Taiwanese children. Serological assays for antibodies against HCV (anti-HCV) and polymerase chain reaction for serum HCV ribonucleic acid (RNA) and HGV RNA were performed. The prevalence of anti-HCV and HGV RNA was 17% and 14%, respectively in 42 polytransfused children. Anti-HCV seropositives had a significantly higher mean age, peak serum transaminase level, and longer transfusion duration than seronegatives, while children with HGV infection usually had no or only mild hepatitis activities. The prevalence of anti-HCV dropped sharply after implementation of anti-HCV screening, however the prevalence of HGV viraemia remained unchanged. Conclusion HGV infection is not uncommon in polytransfused Taiwanese children and the virus does not cause significant hepatitis compared to HCV infection. Current blood donor screening for anti-HCV can effectively protect polytransfused children from HCV infection but the impact of additional screening for HGV markers awaits further studies. Received: 10 October 1996 and in revised form: 26 November 1996 / Accepted 26 November 1996     

Hepatitis B virus mutation in children

Due to the lack of proof reading activity of hepatitis B virus (HBV) polymerase, mutation/variation of the viral sequence is frequently found during long term follow-ups. In the majority of children with chronic HBV infection, wild type HBV is the dominant viral strain during the natural course of chronic HBV infection. During long-term follow-up, HBV precore mutants developed spontaneously in approximately 10 to 24% of children before HBeAg seroconversion, and in around 50% of children after HBeAg seroconversion mutants. Occasionally, children may be infected primarily by mutant strains of HBV. Approximately 36% of children with fulminant hepatitis and 30% of children with acute hepatitis B were infected by precore mutants of HBV transmitted by their mothers or blood donors. In addition, after universal HBV vaccination, HBV surface gene variants emerge or are selected under the immune pressure generated by the host or by administration of hepatitis B immune globulin and hepatitis B vaccination. In HBV DNA positive children from four sequential surveys in Taiwan, the prevalence of hepatitis B surface gene a determinant mutants increased from 7.8% before the vaccination program, to 19.6%, 28.1%, and 23.1% at 5, 10, and 15 years after the program. Nucleoside analogue may also induce mutant strains, which reduces the antiviral effects. The most common example is the YMDD mutation of the HBV polymerase gene after antiviral therapy with lamivudine. It developed in 19% of the treated children. In conclusion, children may be infected primarily by mutant strains of HBV either naturally during acute HBV infection. Those infected with wild type HBV initially may develop mutant strains gradually during the course of chronic infection under the host immune pressure. Vaccine escape mutants may develop after immunoprophylaxis. In addition, antiviral therapy with nucleoside anlogues may also induce drug resistant mutant strains. Understanding the viral mutation status will help to design accurate strategies of immunoprophylaxis and antiviral therapy against HBV infection.     

Management of chronic hepatitis B and C virus infections

Hepatitis B and C virus (HBV and HCV) infections present an important health problem causing significant morbidity and mortality on a worldwide scale. The younger the subjects infected, the higher the risk predisposing to progression towards chronic infection. Treatment of chronic HBV and HCV infections is aimed at reducing hepatic inflammation and thus improving the symptoms, decreasing the likelihood of long-term sequelae such as hepatocellular carcinoma, and increasing the survival rate. Interferon accelerates the spontaneous course of chronic HBV infection in children with greater disease activity and lower levels of replication. There is limited information on the use of lamivudine and its long-term benefit in children with chronic HBV infection. The response of combination therapy with IFN and ribavirin in children with chronic HCV infection is still under investigation. The long-term clinical and virological effects of various drugs used in chronic HBV and HCV infections on children remain to be evaluated.     

Increased risk of chronic hepatitis in children with cancer

BACKGROUND: There is a risk of viral hepatitis for children with cancer. Both hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in countries with high prevalence cause major problems in the management of cancer patients. In this study, we evaluated the incidence and chronicity of HBV and HCV infections in children with malignant diseases receiving chemotherapy. PROCEDURE: One hundred ninety-eight children with cancer (mean age = 7.5 +/- 2.5 years) and 100 healthy children as a control group were screened for HBV and HCV. Liver function tests, the number of transfusions, HBV and HCV serology were regularly monitored. In seropositive children, HBV-DNA and HCV-RNA were measured. Chronic hepatitis was defined as having an alanine aminotransferase (ALT) level three times of upper normal limit, positive HBV and HCV antigenemia for longer than 6 months. Liver biopsies were performed in all children with chronic hepatitis. The relationship between the chronic hepatitis and study parameters was statistically analyzed. RESULTS: HBsAg positivity, anti-HCV, and mixed (HBV and HCV) infection were found in 11.6, 5.5, 2% of children, respectively. Most HBV infected children developed chronic hepatitis (48%) while 26 and 21.7% became carriers and immune, respectively. One died of acute fulminant HBV hepatitis. Of HCV infected children, 63.6% also had positive HCV-RNA. Four children with mixed infection (100%) all progressed to chronic hepatitis. In this setting, chronic hepatitis was observed in 22 of 38 infected children (57.8%). The majority had leukemia and lymphoma. Children with HBsAg antigenemia developed chronic hepatitis in shorter time than HCV positive children (median 13 months vs. 51 months, P < 0.001). CONCLUSION: We observed an increased incidence of chronic hepatitis and even mortality due to HBV infection. This suggests that HBV and HCV infections are serious causes of morbidity and mortality in children with cancer.     

乙型肝炎病毒母婴传播影响因素探讨

目的：探讨乙型肝炎病毒(HBV)母婴传播的影响因素,寻求降低婴儿HBV感染率的方法。方法：HBV携带及慢性乙型肝炎孕妇共635例,分别比较不同血HBV DNA滴度,不同分娩方式（剖宫产或自然分娩）,以及不同肝功能状态孕妇所生婴儿出生时及3月龄时HBV的感染率。新生儿生后12 h内肌注乙肝免疫球蛋白200 U 及重组酵母乙肝疫苗10 μg;生后即刻显示血清HBV感染存在者,14 d时再肌注乙肝免疫球蛋白200 U。结果：孕妇高滴度组（HBV DNA>105拷贝/mL）所生新生儿出生时（14.4% vs 4.1%,P<0.01）与3月龄时（4.7% vs 0,P<0.01）HBV感染率均高于低滴度组（HBV DNA ≤105拷贝/mL）。两组新生儿3月龄时HBV感染率均低于出生时（P<0.05）。自然分娩的孕妇其婴儿出生时HBV感染率明显高于剖宫产组（P<0.01）,但3月龄时,两组感染率接近。HBV携带孕妇所生婴儿出生时HBV感染率明显高于慢性乙型肝炎孕妇所生婴儿（P<0.01）,但3月龄时两组婴儿HBV感染率亦接近。结论：孕妇血清HBV DNA水平与新生儿HBV宫内感染密切相关,故降低孕妇血清HBV DNA水平可能成为减少新生儿HBV感染的一种有效途径。在乙肝免疫球蛋白及重组酵母乙肝疫苗的双重保护下,孕妇的分娩方式与肝功能状态对HBV母婴传播无影响。     

Post-transfusion chronic hepatitis C in children

Two hundred and twenty-six patients who received blood products for open-heart surgery in childhood were screened by a second-generation enzyme-linked immunosorbent assay and with surrogate markers for hepatitis C virus (HCV) infection, such as alanine aminotransferase (ALT). Twenty-two (14%) of the 161 recipients who received blood products before 1989 and none of the subjects who had received blood products after 1990 (the year that the blood bank began to screen for HCV antibody) were HCV seropositive. Virologic and histologic studies showed that 10 (45%) of 24 seropositive patients had persistent hepatitis C virus infection, many with ongoing hepatitis. The remaining 12 seropositive patients with absent HCV RNA had normal ALT levels, indicating resolved hepatitis C infection. Enrolment in screening is important to detect chronic hepatitis C in children who received blood products prior to screening of blood donors for HCV antibody.     

Delta-hepatitis

Investigations were conducted for serological evidence of hepatitis B virus (HBV) and hepatitis D virus (HDV) infections in children suffering from acute viral hepatitis. A total of 52 serum samples were analysed by enzyme immunoassay. Of these, 18 (24%) were positive for hepatitis B virus markers and 34 (65.4%) were negative. Delta virus infection was detected in 6/18 (33%) hepatitis B patients. A significant finding was, that of the 34 patients negative for hepatitis B, 4 (12%) were positive only for HDV although the latter can only occur as a coexistent infection with hepatitis B virus. From the present study it may be inferred that delta virus infection is prevalent in children and absence of HBV markers does not rule out hepatitis D.     

乙型肝炎病毒感染患儿肝内乙型肝炎X抗原的表达

应用抗ＨＢｘ单克隆抗体，以生物素。卵白素复合物法对４０例乙型肝炎病毒感染患儿肝内乙型肝炎Ｘ抗原（ＨＢｘＡｇ）的表达进行研究。结果表明，ＨＢｘＡｇ阳性率７０．７％，其中慢性活动性肝炎高达８８．９％；慢性活动性肝炎和肝硬化的阳性率明显高于急性肝炎和慢性迁延性肝炎（Ｐ＜０．０１）。ＨＢｃＡｇ阳性率７３．２％，各病理类型间无显著性差异；ＨＢｘＡｇ和ＨＢＣＨｇ的表达无明显一致性（Ｐ＞０．０５）。ＨＢｘＡｇ在肝细胞中呈胞浆型、浆膜型、膜型和核型，还表达于胆管细胞。提示ＨＢｘＡｇ肝内的表达与乙型肝炎病毒慢性感染有一定关系，但与病毒复制无明显一致性。     

Hepatitis A,B and C seroprevalence in Pakistan

A cross sectional study was conducted to determine the seroprevalence of Hepatitis A, B, and C virus in healthy Pakistani children. HAV IgG antibody was assayed in 258 subjects and it was found that 94% children by 5 years of age had HAV IgG-antibody. The overall seroprevalence of HAV IgG antibody was 55.8% and IgM 5.3%. HBVsAb levels assayed in 236 healthy children showed a seroprevalence of 2.97%. Similarly, HCV antibody seroprevalence was found to be a low 0.44% in healthy children. HAV is a major cause of Hepatitis, as compared to HBV and HCV which are of low endemicity.     

Clinical implications of mother-to-child transmission of HCV

Testing for vertical transmission of hepatitis C virus (HCV) infection in infants and children will enable early identification of the majority of uninfected HCV-exposed infants and children, and will provide significant emotional relief for the parents.

Conclusion: The small percentage of infected children should be offered enrolment in well-designed clinical trials of optimal medical management for prevention of the predicted long-term outcomes of chronic HCV infection: chronic hepatitis, cirrhosis and hepatocellular carcinoma.     

NASPGHAN practice guidelines: Diagnosis and management of hepatitis C infection in infants, children, and adolescents

Hepatitis C virus (HCV) is an RNA virus that affects >180 million individuals worldwide with a high propensity for chronic infection. Children with HCV infection differ from adults in several ways including some modes of transmission, rates of clearance, progression of fibrosis, and the duration of potential chronic infection when acquired at birth. Since the discovery of HCV in 1989, there have been significant advances in the understanding of the virology and natural history of chronic HCV infection in children. In addition, there are now several treatment options for children with chronic hepatitis C infection and many new therapies on the horizon. As a consequence, the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition brought together experts in pediatric hepatology to review the available data in children and provide clinicians with approaches to the diagnosis, management, and prevention of HCV infection in children and adolescents. The guideline details the epidemiology and natural history of HCV infection in children, the diagnostic workup, monitoring and treatment of disease, and provides an update on future treatment options and areas of research.     

Hepatitis B and C viruses in infants and young children

Advances during the past 20 years have led to a better understanding of the prevention, diagnosis, and treatment of acute and chronic hepatitis B (HBV) and hepatitis C (HCV) infections in the pediatric population. Universal vaccination and prenatal testing for HBV have decreased the incidence rate of acute HBV infections from more than 3/100,000 to 0.34/100,000 in all children. Diagnosis of chronic HBV is confirmed with positive serologic testing on two occasions at least 6 months apart. Current approved therapies with interferon alpha and lamivudine for children with chronic HBV infection have shown some efficacy, but results have been variable. In contrast, the lack of an effective HCV vaccine and the risk of mother-to-child transmission may increase the number of children with vertically acquired HCV that ultimately go on to develop liver fibrosis or cirrhosis. Diagnosis of HCV in the neonate should be postponed until after the child reaches 1 year of age because infants may have transient viremia. Treatment for HCV infected children has not been studied extensively. Peginterferon alpha-2a and Ribavirin are not currently approved for pediatric use; however, recent studies in children have shown potential benefit. More effective and less toxic therapies for young patients with HBV and HCV are needed, as are methods to interrupt perinatal transmission of HBV and HCV.     

Risks of seroconversion of hepatitis B, hepatitis C and human immunodeficiency viruses in children with multitransfused thalassaemia major

OBJECTIVES: To estimate the risks of seroconversion of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency viruses (HIV) in children with multitransfused thalassaemia at a thalassaemic clinic in Kuala Lumpur, Malaysia. METHODS: Seventy-two children (39 males, median age 11.3 years, 2.5th-97.5th centile: 1.4-19.2 years) with thalassaemia major were studied. The risks of seroconversion of HBV, HCV and HIV were estimated by comparing the seroprevalences of hepatitis B surface antigen (HBsAg), anti-HCV and anti-HIV between a defined starting point and an end point. The end point was the point when latest serological results were available while the starting point was when regular transfusion was commenced, or approximately 5 years before the end point when the duration of transfusion was longer. RESULTS: The median duration of the study was 49 months (range 8-69 months, total 2953 patient-months). There were 2605 transfusion episodes and 4154 units of blood transfused (0.88 transfusion episode/patient per month, 1.41 units of blood transfused/patient per month). There were three new seroconversions for anti-HCV but none for HBsAg and anti-HIV. The risk of seroconversion for HCV was one in 1384 units of blood transfused (95% CI: 4000-472). The seroprevalence rates at the starting and end points were: HBsAg (1%, 1%), anti-HCV (10%, 13%) and anti-HIV (0%, 0%), respectively. CONCLUSIONS: The estimated risk of acquiring HCV infection in children receiving multiple blood transfusions in this study is surprisingly higher than the generally accepted estimated risk. Other routes of transmission may be important. A prospective, multicentre study to estimate such risks more precisely is needed.