Serious hepatitis A: an analysis of patients hospitalized during an urban epidemic in the United States

A Rare Manifestation of Hepatitis A Associated Cryoglobulinemia

Cryoglobulins can precipitate in the blood when exposed to lower temperatures. These abnormal immunoglobulins are more commonly affiliated with Hepatitis C infection but there have been cases reported with Hepatitis A association for which we present this case. The patient was treated with steroids which did show gradual improvement of symptoms but, ultimately, the patient developed renal failure and required temporary hemodialysis. Care should be taken to assess patients with cryoglobulins for other viral serologies besides Hepatitis C.

[Extra hepatic manifestations of hepatitis A]

Viral hepatitis A is characterized by a wide range of clinical pictures ranging from a completely unapparent infection to a fulminant, potentially fatal hepatitis or the classical icteric form. Hepatitis A can develop in an unusual way and extrahepatic manifestations (neurological, renal, haematological, cholecystitis, acute pancreatitis, vasculitis, etc.) can occasionally complicate the course of the disease. Although hepatitis A infection was identified in the early 1970s, there are few or no studies assessing the actual frequency of these complications. They have been studied mainly through clinical case reports. Currently, since the disease has become more common in adults, these complications are being increasingly observed. We present an update on extrahepatic complications during hepatitis A, which should be known by both specialist doctors (infectiologists internists, hepatologists and others) and general practitioners.

Acute benign pleural effusion, a rare presentation of hepatitis A virus: a case report and review of the literature

Introduction

Hepatitis A virus infections are mostly asymptomatic or mildly symptomatic, and generally this disease has a benign course and resolves spontaneously. However, intrahepatic and rarer extrahepatic manifestations can complicate typical cases of acute hepatitis. Pleural effusion is an extremely rare extrahepatic entity with 20 cases reported in literature.

Case presentation

We report herein a recent case of both pleural effusion and ascites accompanying hepatitis A infection in a 5-year-old middle eastern child, diagnosed using serological testing and imaging studies, who was treated with supportive management with full resolution after 2 weeks. In addition, we review available literature regarding hepatitis A virus associated with pleural effusion using PubMed and summarize all reported cases in a comprehensive table.

Results

Literature contains 20 reported cases of serology-confirmed hepatitis A virus presenting with pleural effusion, most in the pediatric population with average age at presentation of 9 years 8 months. The majority of reported patients had right-sided pleural effusion (50%) or bilateral effusion (45%), while only 5% presented with pleural effusion on the left side. Hepatomegaly and ascites occurred concurrently in 80% and 70% respectively. Supportive treatment without invasive procedures (except one chylothorax case) yielded complete recovery in 95% of cases, while only one case progressed to fulminant liver failure followed by death.

Conclusion

Acute hepatitis A virus rarely presents with pleural effusion, usually following a benign course with spontaneous resolution in most patients. Pleural effusion does not change the prognosis or require any invasive treatment. Thus, further invasive procedures are not recommended and would only complicate this self-resolving benign condition.

Hepatitis A: Epidemiology, High-Risk Groups, Prevention and Research on Antiviral Treatment

The hepatitis A virus (HAV) is a leading cause of acute viral hepatitis worldwide. It is transmitted mainly by direct contact with patients who have been infected or by ingesting contaminated water or food. The virus is endemic in low-income countries where sanitary and sociodemographic conditions are poor. Paradoxically, improving sanitary conditions in these countries, which reduces the incidence of HAV infections, can lead to more severe disease in susceptible adults. The populations of developed countries are highly susceptible to HAV, and large outbreaks can occur when the virus is spread by globalization and by increased travel and movement of foodstuffs. Most of these outbreaks occur among high-risk groups: travellers, men who have sex with men, people who use substances, and people facing homelessness. Hepatitis A infections can be prevented by vaccination; safe and effective vaccines have been available for decades. Several countries have successfully introduced universal mass vaccination for children, but high-risk groups in high-income countries remain insufficiently protected. The development of HAV antivirals may be important to control HAV outbreaks in developed countries where a universal vaccination programme is not recommended.

Acute Hepatitis A Causing Severe Hemolysis and Renal Failure in Undiagnosed Glucose-6-Phosphate Dehydrogenase Deficient Patient: A Case Report and Review of the Literature

Infection with hepatitis A virus is usually a self-limited illness that rarely results in fulminant liver failure. Severe hemolysis is an uncommon complication but has been reported in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Here, we report a case with undiagnosed G6PD deficiency who presented with hyperbilirubinemia, severe hemolysis, and acute renal failure precipitated by acute hepatitis A infection.

Pathogenicity and virulence of hepatitis A virus

Hepatitis A is an acute infection of the liver, which is mostly asymptomatic in children and increases the severity with age. Although in most patients the infection resolves completely, in a few of them it may follow a prolonged or relapsed course or even a fulminant form. The reason for these different outcomes is unknown, but it is generally accepted that host factors such as the immunological status, age and the occurrence of underlaying hepatic diseases are the main determinants of the severity. However, it cannot be ruled out that some virus traits may also contribute to the severe clinical outcomes. In this review, we will analyze which genetic determinants of the virus may determine virulence, in the context of a paradigmatic virus in terms of its genomic, molecular, replicative, and evolutionary features.

Polyvalent Human Immune Globulin: A Prospective, Open-Label Study Assessing Anti-Hepatitis A Virus (HAV) Antibody Levels, Pharmacokinetics, and Safety in HAV-Seronegative Healthy Subjects

Background

Analytical data suggesting that immunoglobulin given intramuscularly (IGIM) may have reduced protection against hepatitis A virus (HAV) infection led to an update in the recommended IGIM dose (0.2 ml/kg).

Methods

This prospective, open-label, single-arm clinical study evaluated whether a single 0.2 ml/kg dose of IGIM provided protective levels of anti-HAV antibodies (≥ 10 mIU/ml for up to 60 days) in HAV-seronegative healthy adults.

Results

Of the 28 subjects enrolled and dosed, 26 (93%) completed the study. Mean uncorrected anti-HAV antibody titers peaked at 109 mIU/ml on day 5 and stayed above 10 mIU/ml through day 60 (N = 26). The mean uncorrected anti-HAV antibody titers had a median T_max of 95.33 h, a mean C_max of 118 mIU/ml, and a mean observed T_half of 63.3 days; baseline-corrected titers had a median T_max of 95.33 h, a mean C_max of 114 mIU/ml, and a mean observed T_half of 47.1 days (N = 27). All subjects (28/28) experienced at least 1 treatment-emergent adverse event (TEAE), with a total of 83 TEAEs reported; none was serious, and 96% (80/83) resolved without sequelae. Most (63%) events judged definitely and possibly related to study treatment involved localized pain due to intramuscular injections. There were no serious adverse events and no deaths or discontinuations due to TEAEs.

Conclusions

A single 0.2 ml/kg dose of IGIM provided protective anti-HAV levels for at least 60 days, with acceptable safety and tolerability profiles in healthy subjects. Uncorrected and baseline-corrected pharmacokinetic findings were similar and consistent with the corresponding sampling points in previous research.

Trial Registration

ClinicalTrials.gov Identifier, NCT03351933.

Travel and biologic therapy: travel-related infection risk, vaccine response and recommendations

BACKGROUND

Biologic therapy has revolutionized the management of refractory chronic autoimmune and auto-inflammatory disease, as well as several malignancies, providing rapid symptomatic relief and/or disease remission. Patients receiving biologic therapies have an improved quality of life, facilitating travel to exotic destinations and potentially placing them at risk of a range of infections. For each biologic agent, we review associated travel-related infection risk and expected travel vaccine response and effectiveness.

METHODS

A PUBMED search [vaccination OR vaccine] AND/OR ['specific vaccine'] AND/OR [immunology OR immune response OR response] AND [biologic OR biological OR biologic agent] was performed. A review of the literature was performed in order to develop recommendations on vaccination for patients in receipt of biologic therapy travelling to high-risk travel destinations.

RESULTS

There is a paucity of literature in this area, however, it is apparent that travel-related infection risk is increased in patients on biologic therapy and when illness occurs they are at a higher risk of complication and hospitalization. Patients in receipt of biologic agents are deemed as having a high level of immunosuppression-live vaccines, including the yellow fever vaccine, are contraindicated. Inactivated vaccines are considered safe; however, vaccine response can be attenuated by the patient's biologic therapy, thereby resulting in reduced vaccine effectiveness and protection.

CONCLUSIONS

Best practice requires a collaborative approach between the patient's primary healthcare physician, relevant specialist and travel medicine expert, who should all be familiar with the immunosuppressive and immunomodulatory effects resulting from the biologic therapies. Timing of vaccines should be carefully planned, and if possible, vaccination provided well before established immunosuppression.

An extra priming dose of hepatitis A vaccine to adult patients with rheumatoid arthritis and drug induced immunosuppression - A prospective, open-label, multi-center study

BACKGROUND

Previous studies have indicated that a pre-travel single dose of hepatitis A vaccine is not sufficient as protection against hepatitis A in immunocompromised travelers. We evaluated if an extra dose of hepatitis A vaccine given shortly prior to traveling ensures seroconversion.

METHOD

Patients with rheumatoid arthritis (n = 69, median age = 55 years) treated with Tumor Necrosis Factor inhibitor(TNFi) and/or Methotrexate (MTX) were immunized with two doses of hepatitis A vaccine, either as double dose or four weeks apart, followed by a booster dose at six months. Furthermore, 48 healthy individuals, median age = 60 years were immunized with two doses, six months apart. Anti-hepatitis A antibodies were measured at 0, 1, 2, 6, 7 and 12 months.

RESULTS

Two months after the initial vaccination, 88% of the RA patients had protective antibodies, compared to 85% of the healthy individuals. There was no significant difference between the two vaccine schedules. At twelve months, 99% of RA patients and 100% of healthy individuals had seroprotective antibodies.

CONCLUSION

An extra priming dos of hepatitis A vaccine prior to traveling offered an acceptable protection in individuals treated with TNFi and/or MTX. This constitutes an attractive pre-travel solution to this vulnerable group of patients.

International travelers receiving pharmacological immunosuppression: Challenges and opportunities

There is an increasing number of international travelers receiving immunosuppressive therapy due to the better life expectation and quality offered by this kind of treatment. The complexity of pre-travel counseling in these patients lies in their greater susceptibility to certain travel-related infections and the potential severity of these, as well as in the contraindications and interactions that may occur between certain vaccines and/or prophylaxis and their base therapy. Counseling the traveler represents a challenge for clinicians who have to tailor vaccinations and other recommended preventive measures to the immunosuppressed patients. Thus, pre-travel assessment of patients receiving immunosuppressive therapy should be performed in a specialized Traveler's Medical Unit, working closely with the specialist doctor in charge of treating the patient's underlying medical condition. The purpose of this article is to review available evidence on the health recommendations indicated in the pre-travel administration of vaccines, antimalarial chemoprophylaxis and other measures to prevent communicable diseases in travelers receiving immunosuppressive therapy.

Type A viral hepatitis: A summary and update on the molecular virology, epidemiology, pathogenesis and prevention

Although epidemic jaundice was well known to physicians of antiquity, it is only in recent years that medical science has begun to unravel the origins of hepatitis A virus (HAV) and the unique pathobiology underlying acute hepatitis A in humans. Improvements in sanitation and the successful development of highly efficacious vaccines have markedly reduced the worldwide prevalence and incidence of this enterically-transmitted infection over the past quarter century, yet the virus persists in vulnerable populations and remains a common cause of food-borne disease outbreaks in economically-advantaged societies. Reductions in the prevalence of HAV have led to increases in the median age at which infection occurs, often resulting in more severe disease in affected persons and paradoxical increases in disease burden in some developing nations. Here, we summarize recent advances in the molecular virology of HAV, an atypical member of the Picornaviridae family, survey what is known of the pathogenesis of hepatitis A in humans and the host-pathogen interactions that typify the infection, and review medical and public health aspects of immunisation and disease prevention.

Hepatitis B and C

Chronic viral hepatitis is a global health threat and financial burden. Hepatitis B and C viruses (HBV and HCV) are the most common causes of chronic viral hepatitis in the United States. Most cases are asymptomatic before adulthood. Research has resulted in effective therapy for HCV and the promise of effective therapies for HBV. For HCV, therapy is pegylated interferon and ribavirin. Clinical trials with effective direct-acting antiviral agents are underway in pediatrics. For HBV, approved agents are alpha-interferon, lamivudine, adefovir, tenofovir, and entecavir. However, treatment seldom results in functional cure and more effective therapies are urgently needed.

Frequency and prognosis of acute pancreatitis associated with fulminant or non-fulminant acute hepatitis A: A systematic review

BACKGROUND

Acute pancreatitis (AP) in patients with fulminant viral hepatitis is well recognized and its mortality depends on the severity of hepatitis rather than pancreatitis. Acute pancreatitis associated with non-fulminant acute hepatitis A (AHA) has been rarely described, and is considered to have a benign course with good response to conservative management.

OBJECTIVE

To perform a systematic review of the frequency and prognosis of AP associated with fulminant or non-fulminant AHA.

RATIONALE

An increasing number of reports describe AP associated with AHA. Some life-threatening complications related to AP may occur, and death has been reported. In addition, it is possible that early diagnosis of these cases may help in reducing the morbidity and mortality.

DATA SOURCES

Ovid Medline In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, Scopus, Google Scholar, and reference lists of relevant articles.

STUDY SELECTION

All available studies discussing AP associated with fulminant or non-fulminant AHA.

DATA EXTRACTION AND ASSESSMENT

Two blinded independent observers extracted and assessed the frequency of AP associated with AHA based on large studies including all cases of AHA observed during a prolonged period of time, diagnosis of AHA based on anti-HAV IgM, diagnosis of fulminant hepatitis (FH) based on the American Association for the study of Liver Diseases (AASLD) position paper, diagnosis of AP based on the American College of Gastroenterology (ACG) guidelines, diagnosis of AP associated with AHA based on Makharia's association, and diagnosis of AP severity based on the Revision of the Atlanta Classification (RAC). We have developed a tool for risk of bias assessment of case reports and case-series and applied it to the included studies.

RESULTS

The frequency of reported AP associated with AHA is 0-0.1%. Thirty-eight publications with a total of 54 patients meeting the inclusion criteria have been published. Twenty-two studies had a low risk for bias, 10 had moderate risk and 6 had high risk. Patients originated from all continents but most of them were from Asia. The median age at diagnosis was 16 years (range: 2-81) with a male to female ratio of 2. The median interval between the onset of jaundice and onset of AP pain was 4 days (range: 0-30). AP was severe in 9% of patients. The median hospital stay for AP was 8 days (range: 3-35). Most cases occur in patients without FH (94%). Mortality was reported in 2 patients (3.7%).

CONCLUSION

Acute pancreatitis associated with AHA is rare with an estimated frequency of 0-0.1%. Fifty-four documented cases, mostly in Asian patients, have been reported. The median age of patients is 16 years with a M/F ratio of 2. Acute pancreatitis occurs less than one week after the onset of jaundice and mostly in patients without FH. Acute pancreatitis in this setting is severe in 9% of patients with a mortality rate similar to all other causes of AP.

Hospitalization and mortality due to hepatitis A in Taiwan: a 15-year nationwide cohort study

Hepatitis A virus (HAV) is the most common food-borne hepatitis in the world. The study objectives were (i) to describe the epidemiology of HAV-related hospitalizations during 1997-2011 in Taiwan, (ii) to examine the age effect on the length of stay (LOS) in hospital and (iii) to study the factors associated with death. The hospitalized cases were identified from the Taiwan National Health Insurance Research Database between 1997 and 2011 by ICD-9-CM code of 070.0/070.1. Patient sex, birthday, dates of hospitalization and death were analysed. A total of 3990 HAV-hospitalized cases, males 2467 (62%), were identified. The LOS increased as patients' age increased. The overall mortality rate was 16.8 per 1000 hospitalizations. Males had significantly higher case fatality rate than females (20.7 vs 10.5 per 1000 cases). The adjusted odds ratio (aOR) for death rose by age and increased rapidly over 40 years of age. The aOR and 95% confidence interval [95%CI] for aged 40-59 years and aged over 60 years were 7.89 (1.06-58.98) and 14.88 (2.02-109.40) compared to aged 0-19 years, respectively. Patients with chronic liver disease and cirrhosis had significantly higher risk of death (aOR=1.03 [1.01-1.04]), compared to those without liver disease. However, patients with liver disease, but no cirrhosis did not have higher risk of death (aOR=1.00 [0.99-1.01]). The aOR [95%CI] for LOS >9 day was 3.26 (1.96-5.40) compared to cases with LOS ≤9 days. Male sex, age over 40 years, cirrhotic liver and long LOS are significant factors associated with death in HAV-hospitalized cases.

Risk factors for hospitalisation and associated costs among patients with hepatitis A associated with imported pomegranate arils, United States, 2013

OBJECTIVES

To assess hospitalisation risk factors and economic effects associated with a multistate hepatitis A outbreak in 2013.

STUDY DESIGN

Retrospective case series.

METHODS

Eligible outbreak-related cases confirmed by September 1, 2013, were defined as acute hepatitis symptoms and positive IgM anti-hepatitis A during March 15-August 12 among patients who consumed the food vehicle or had the outbreak genotype. We reviewed medical records, comparing demographic and clinical characteristics among hospitalized and non-hospitalized patients; we used logistic regression analysis to identify factors associated with hospitalization. We interviewed patients regarding symptom duration and healthcare usage and estimated per-patient and total costs. Health departments reported outbreak-related personnel hours.

RESULTS

Medical records were reviewed for 147/159 (92%) eligible patients; median age was 48 (range: 1-84) years, and 64 (44%) patients were hospitalized. Having any chronic medical condition was independently associated with hospitalisation (odds ratio, 3.80; 95% confidence interval, 1.68-8.62). Interviews were completed for 114 (72%) eligible patients; estimated per-patient cost of healthcare and productivity loss was $13,467 for hospitalized and $2138 for non-hospitalized patients and $1,304,648 for all 165 outbreak-related cases. State and local public health personnel expenditures included 82 h and $3221/outbreak-related case.

CONCLUSIONS

Hospitalisations in this outbreak were associated with chronic medical conditions and resulted in substantial healthcare usage and lost productivity. These data can be used to inform future evaluation of expansion of hepatitis A vaccination recommendations to include adults with chronic medical conditions.

Self-reported hepatitis A vaccination as a predictor of hepatitis A virus antibody protection in U.S. adults: National Health and Nutrition Examination Survey 2007-2012

OBJECTIVES

To estimate the predictive value of self-reported hepatitis A vaccine (HepA) receipt for the presence of hepatitis A virus (HAV) antibody (anti-HAV) from either past infection or vaccination, as an indicator of HAV protection.

METHODS

Using 2007-2012 National Health and Nutrition Examination Survey data, we assigned participants to 4 groups based on self-reported HepA receipt and anti-HAV results. We compared characteristics across groups and calculated three measures of agreement between self-report and serologic status (anti-HAV): percentage concordance, and positive (PPV) and negative (NPV) predictive values. Using logistic regression we investigated factors associated with agreement between self-reported vaccination status and serological results.

RESULTS

Demographic and other characteristics varied significantly across the 4 groups. Overall agreement between self-reported HepA receipt and serological results was 63.6% (95% confidence interval [CI] 61.9-65.2); PPV and NPV of self-reported vaccination status for serological result were 47.0% (95% CI 44.2-49.8) and 69.4% (95% CI 67.0-71.8), respectively. Mexican American and foreign-born adults had the highest PPVs (71.5% [95% CI 65.9-76.5], and 75.8% [95% CI 71.4-79.7]) and the lowest NPVs (21.8% [95% CI 18.5-25.4], and 20.0% [95% CI 17.2-23.1]), respectively. Young (ages 20-29 years), US-born, and non-Hispanic White adults had the lowest PPVs (37.9% [95% CI 34.5-41.5], 39.1% [95% CI, 36.0-42.3], and 39.8% [36.1-43.7]), and the highest NPVs (76.9% [95% CI 72.2-81.0, 78.5% [95% CI 76.5-80.4)], and 80.6% [95% CI 78.2-82.8), respectively. Multivariate logistic analyses found age, race/ethnicity, education, place of birth and income to be significantly associated with agreement between self-reported vaccination status and serological results.

CONCLUSIONS

When assessing hepatitis A protection, self-report of not having received HepA was most likely to identify persons at risk for hepatitis A infection (no anti-HAV) among young, US-born and non-Hispanic White adults, and self-report of HepA receipt was least likely to be reliable among adults with the same characteristics.

Trends in disease and complications of hepatitis A virus infection in the United States, 1999-2011: a new concern for adults

BACKGROUND

In recent years, few US adults have had exposure and resultant immunity to hepatitis A virus (HAV). Further, persons with liver disease have an increased risk of adverse consequences if they are infected with HAV.

METHODS

This study used 1999-2011 National Notifiable Diseases Surveillance System and Multiple Cause of Death data to assess trends in the incidence of HAV infection, HAV-related hospitalization, and HAV-related mortality.

RESULTS

During 1999-2011, the incidence of HAV infection declined from 6.0 cases/100 000 to 0.4 cases/100 000. Similar declines were seen by sex and age, but persons aged ≥80 years had the highest incidence of HAV infection in 2011 (0.8 cases/100 000). HAV-related hospitalizations increased from 7.3% in 1999 to 24.5% in 2011. The mean age of hospitalized cases increased from 36.0 years in 1999 to 45.1 years in 2011. While HAV-related mortality declined, the mean age at death among decedents with HAV infection increased from 48.0 years in 1999 to 76.2 years in 2011. The median age range of decedents who had HAV infection and a liver-related condition was 51.0 to 68.0 years.

CONCLUSIONS

Although vaccine-preventable, HAV-related hospitalizations increased greatly, mostly among adults, and liver-related conditions were frequently reported among HAV-infected individuals who died. Public health efforts should focus on the need to assess protection from hepatitis A among adults, including those with liver disease.

Clinical Factors and Viral Load Influencing Severity of Acute Hepatitis A

Background and Aims

Clinical manifestations of hepatitis A virus (HAV) infection vary from mild to fulminant hepatic failure (FHF) in adults. We investigated the relationship between laboratory findings, including viral load, and clinical outcomes in patients with acute hepatitis A (AHA) and evaluated predictive factors for severe acute hepatitis (s-AH).

Methods

We analyzed the clinical manifestations of AHA in 770 patients. Patients with a prothrombin time (PT) of less than 40% of normal were classified as s-AH and included 4 patients with FHF, 11 patients with acute renal failure, and 3 patients with prolonged jaundice (n = 128). Other patients were defined as mild acute hepatitis (m-AH) (n = 642). Serum samples were obtained from 48 patients with acute hepatitis A. Among them, 20 with s-AH, and 28 with m-AH, were tested for HAV RNA titer.

Results

In a multivariate analysis, age (HR = 1.042, P = 0.041), peak creatinine (HR = 4.014, P = 0.001), bilirubin (HR = 1.153, P = 0.003), alanine aminotransferase (ALT) (HR = 1.001, P<0.001), initial lactate dehydrogenase (LDH) (HR = 1.000, P = 0.045) and total cholesterol (HR = 0.978, P<0.001) were independent factors for s-AH. Serum HAV RNA was detected in 20/20 (100%) patients with s-AH and 22/28 (78.6%) patients with m-AH. In a multivariate analysis of the 48 patients who were tested for HAV RNA, peak ALT (HR = 1.001, P = 0.004) and HAV RNA titer (HR = 2.076, P = 0.012) were independent factors for s-AH.

Conclusions

Clinical factors including age, peak creatinine, bilirubin, ALT, initial LDH and total cholesterol were independent factors for s-AH in a multivariate analysis. In particular, HAV load strongly correlated with the severity of hepatitis A.

HAV Immunity in Iranian Medical Students

BACKGROUND

Hepatitis A, a fecal-oral transmitted disease, which has been considered endemic in developing countries, seems to change its pattern in developing countries because of their improved socioeconomic status.

OBJECTIVES

In the present study, we aimed to determine the need of vaccination in 270 students at AJA University of Medical Sciences.

MATERIALS AND METHODS

The serum level of anti-HAV antibody was checked in 270 students of AJA University of medical students, and effect of different factors, including age, gender, pre-university entrance exam region, familial education, familial income, clean water availability, and previous history of jaundice were tested.

RESULTS

Of total 270 students, 30 were female. Their age ranged between 18 and 30 years old with the mean age of 20.58 years and just 34% of students had positive level of anti-HAV antibody. Age and sex had no role in positive serum level of anti-HAV antibody. According to analyzed data, lack of clean water availability, pre-university entrance exam region, lower family education, and poor health status estimation increased statistically the risk of HAV infection.

CONCLUSIONS

Because 66% of students were anti-HAV antibody negative and they will work as health care workers in future, our study suggest vaccinating all students accepted at AJA University of Medical Sciences.

Recent advances in management of acute liver failure

Acute liver failure (ALF) is a life-threatening illness, where a previously normal liver fails within days to weeks. Sudden loss of synthetic and detoxification function of liver results in jaundice, encephalopathy, coagulopathy, and multiorgan failure. The etiology of ALF varies demographically. The mortality of ALF is as high as 40-50%. The initial care of patients with ALF depends on prompt recognition of the condition and early detection of etiology. Management includes intensive care support, treatment of specific etiology if present and early detection of candidates for liver transplantation. Liver transplantation remains the only therapeutic intervention with proven survival benefit in patients with irreversible ALF. Living related liver transplantation, auxiliary liver transplantation, and  ABO-incompatible liver transplantation are coming up in a big way. Liver assist devices and hepatocyte transplant remain experimental and further advances are required. Public health measures to control hepatitis A, B, E, and drug-induced liver injury will reduce the incidence and mortality of ALF.

A rare presentation of hepatitis a infection with extrahepatic manifestations

Hepatitis A has a variety of associated extrahepatic manifestations that clinicians should be aware of for early diagnosis and treatment. We report a unique case of hepatitis A presenting with multiple extrahepatic manifestations not previously described in a single patient. A 34-year-old male presented with sudden onset of left sided facial pain, swelling, and skin rash, with diffuse body pains and muscle weakness, and was found to be positive for hepatitis A immunoglobulin M (IgM). He was initially started on antibiotics for concerns of bacterial parotitis but did not show any improvement. A punch biopsy of his mandibular rash and swelling was done which showed lymphohistiocytic infiltration with a few eosinophils. A trial of prednisone resulted in improvement of his symptoms. Clinicians should be aware to look for hepatitis A infection in a patient with atypical clinical picture causing a widespread systemic inflammatory response. Treatment with prednisone may result in resolution.

Clinical features and risk factors for severe complications among patients with acute hepatitis A virus infection in the Jeonbuk Province of Korea

BACKGROUND/AIMS

The frequency of symptomatic acute HAV infections in adulthood are increasing in Korea. This study analyzes the clinical severity in patients with acute HAV infection and investigates risk factors associated with three severe complications: prolonged cholestasis, acute kidney injury, and acute liver failure.

METHODS

We performed a retrospective analysis of 726 patients diagnosed from January 2006 to December 2010 at three tertiary hospitals in Jeonbuk Province, Republic of Korea with acute HAV infection.

RESULTS

In the group of 726 patients, the mean age was 30.3 years, 426 (58.6%) were male, and 34 (4.7%) were HBsAg positive. Severe complications from acute HAV infection occurred as follows: prolonged cholestasis in 33 (4.6%), acute kidney injury in 17 (2.3%), and acute liver failure in 16 (2.2%). Through multivariate analysis, age ≥40 years (OR 2.63, p=0.024) and peak PT (INR) ≥1.5 (OR 5.81, p=0.035) were found to be significant risk factors for prolonged cholestasis. Age ≥40 years (OR 5.24, p=0.002) and female gender (OR 3.11, p=0.036) were significant risk factors for acute kidney injury. Age ≥40 years (OR 6.91, p=0.002), HBsAg positivity (OR 5.02, p=0.049), and peak total bilirubin (OR 1.11, p=0.001) were significant risk factors for acute liver failure.

CONCLUSIONS

Age ≥40 years, female gender, HBsAg positivity, peak PT (INR) ≥1.5, and peak total bilirubin were significant risk factors for severe complications in acute HAV infections.

Whole genome sequencing to identify host genetic risk factors for severe outcomes of hepatitis a virus infection

Acute liver failure is a severe, but rare, outcome of hepatitis A virus infection. Unusual presentations of prevalent infections have often been attributed to pathogen-specific immune deficits that exhibit Mendelian inheritance. Genome-wide resequencing of unrelated cases has proven to be a powerful approach for identifying highly penetrant risk alleles that underlie such syndromes. Rare mutations likely to affect protein expression or function can be identified from sequence data, and their association with a similarly rare phenotype rests on their existence in multiple affected individuals. A rare or novel sequence variant that is enriched to a significant degree in a genetically diverse cohort suggests a candidate susceptibility allele. Whole genome sequencing of ten individuals from ethnically diverse backgrounds with HAV-associated acute liver failure was performed. A set of rational filtering criteria was used to identify genetic variants that are rare in the population, but enriched in this cohort. Single nucleotide polymorphisms, insertions, and deletions were considered and autosomal dominant, autosomal recessive, and polygenic models were applied. Analysis of the protein-coding exome identified no single gene with putatively deleterious mutations shared by multiple individuals, arguing against a simple Mendelian model of inheritance. A number of rare variants were significantly enriched in this cohort, consistent with a complex and genetically heterogeneous trait. Several of the variants identified in this genome-wide study lie within genes important to hepatic pathophysiology and are candidate susceptibility alleles for hepatitis A virus infection.

Hepatitis A vaccine for immunosuppressed patients with rheumatoid arthritis: a prospective, open-label, multi-centre study

BACKGROUND

Hepatitis A vaccine is the most frequently used travel vaccine, yet data are scarce about its ability to induce protection in patients with concurrent immunosuppressive treatment. We assessed the immunogenicity of this vaccine in rheumatoid arthritis (RA) patients treated with tumour necrosis factor-inhibitors (TNFi) and/or methotrexate (MTX).

METHODS

Hepatitis A vaccine was administered to non-immune RA patients at 0 and 6 months. Hepatitis A virus (HAV) antibodies were assessed at 0, 1, 6, 7, 12, and 24 months with a quantitative Chemiluminescent Microparticle Immuno Assay (CMIA) for HAV-IgG. Samples from month 1, 6, and 7 were, in addition, analysed with a microparticle EIA (MEIA) for anti-HAV IgM + IgG.

RESULTS

The final study population consisted of 53 patients treated with TNFi (n = 15), TNFi + MTX (n = 21) or MTX (n = 17). One and six months after the first dose, 10% and 33% of the patients had attained seroprotection. One and six months after the second dose 83% and 72% were seroprotected. At month 24, 86% of the vaccinees showed protective levels.

CONCLUSIONS

Two doses of hepatitis A vaccine at a 6-month interval provided protection for most immunosuppressed RA patients. A single dose does not seem to afford sufficient protection to this group of patients.

Hepatitis A in children- clinical course, complications and laboratory profile

OBJECTIVE

To study the course and complications of hepatitis A in children.

METHODS

Seventy eight children diagnosed as acute viral hepatitis A by IgM antiHAV were prospectively studied for involvement of other systems and complications.

RESULTS

The mean age of children was 7.85 ± 3.4 y. Jaundice was present in all the patients as this was the inclusion criteria. Fever was present in 82.1 %, hepatomegaly in 98.7 % and splenomegaly in 39.7 %. More than 5 fold rise in Aspartate transaminase (AST) and Alaninetransaminase (ALT), were seen in 62 cases (79.5 %) and 55 cases (70.5 %) respectively. Coagulopathy (Prothrombin time INR > 1.5) was observed in 12 cases (15.4 %) and abnormal APTT in 10 cases (12.8 %). Thrombocytopenia was observed in 5.1 % of children and 8.9 % had more than 2 hematological abnormalities. Ascites was noted in 35 cases (44.9 %), gallbladder wall thickening in 32 cases (41 %) and pleural effusion in 11 cases (14.1 %). Acute renal failure, acute glomerulonephritis and acute pancreatitis were present in 1 case (1.3 %) each. Raised CK-MB values more than 3 times the normal was noted in 5 cases (6.4 %). On follow up, most of the children recovered completely by 2 mo and prolonged cholestasis was observed in 2 of them. In the present study mortality was 1.3 % and it was attributable to fulminant hepatic failure.

CONCLUSIONS

Eventhough hepatitis A infection is a self-limiting disease, extrahepatic manifestations and mortality are not uncommon. All cases should be followed up till complete recovery and only a strong index of suspicion will enable us to recognize the complications.

Liver physiology and liver diseases in the elderly

The liver experiences various changes with aging that could affect clinical characteristics and outcomes in patients with liver diseases. Both liver volume and blood flow decrease significantly with age. These changes and decreased cytochrome P450 activity can affect drug metabolism, increasing susceptibility to drug-induced liver injury. Immune responses against pathogens or neoplastic cells are lower in the elderly, although these individuals may be predisposed to autoimmunity through impairment of dendritic cell maturation and reduction of regulatory T cells. These changes in immune functions could alter the pathogenesis of viral hepatitis and autoimmune liver diseases, as well as the development of hepatocellular carcinoma. Moreover, elderly patients have significantly decreased reserve functions of various organs, reducing their tolerability to treatments for liver diseases. Collectively, aged patients show various changes of the liver and other organs that could affect the clinical characteristics and management of liver diseases in these patients.

Hepatitis A virus infection during pregnancy in Korea: Hepatitis A infection on pregnant women

Objective

Although there is a large body of data on acute hepatitis A virus (HAV) worldwide, data regarding the occurrence of HAV during pregnancy is limited. It is commonly acknowledged that HAV is not associated with severe outcomes or complications during pregnancy. In contrast, there are several reported cases of vertical HAV transmission. Moreover, it has been recently reported that HAV infection during pregnancy is associated with gestational complications. In Korea, the incidence of HAV infection has increased from 317 cases in 2002 to 13,117 cases in 2009. However, HAV infection during pregnancy is rarely reported in Korea.

Methods

This study was conducted as a retrospective cohort series of pregnant women presenting to Korea University Medical Center between January 2000 and October 2009 in whom a diagnosis of HAV infection was made.

Results

During study period, there were 12 cases of HAV in pregnant women, including two cases with preterm contraction, two cases with cholestatic hepatitis, and one case with fetal ascites and intra-abdominal calcification.

Conclusion

HAV infection during pregnancy is associated with high prevalence of maternal and fetal complications. Because the incidence of HAV infection in women of reproductive age is increasing, a further focus on preventing HAV infection during pregnancy is warranted.

Hepatitis A virus: host interactions, molecular epidemiology and evolution

Infection with hepatitis A virus (HAV) is the commonest viral cause of liver disease and presents an important public health problem worldwide. Several unique HAV properties and molecular mechanisms of its interaction with host were recently discovered and should aid in clarifying the pathogenesis of hepatitis A. Genetic characterization of HAV strains have resulted in the identification of different genotypes and subtypes, which exhibit a characteristic worldwide distribution. Shifts in HAV endemicity occurring in different parts of the world, introduction of genetically diverse strains from geographically distant regions, genotype displacement observed in some countries and population expansion detected in the last decades of the 20th century using phylogenetic analysis are important factors contributing to the complex dynamics of HAV infections worldwide. Strong selection pressures, some of which, like usage of deoptimized codons, are unique to HAV, limit genetic variability of the virus. Analysis of subgenomic regions has been proven useful for outbreak investigations. However, sharing short sequences among epidemiologically unrelated strains indicates that specific identification of HAV strains for molecular surveillance can be achieved only using whole-genome sequences. Here, we present up-to-date information on the HAV molecular epidemiology and evolution, and highlight the most relevant features of the HAV-host interactions.

Acute liver failure

Untreated acute liver failure (ALF) has a poor outcome and so rapid diagnosis and management is vital if the patient is to survive. ALF has such profound and widespread physiological consequences that whenever possible, patients with ALF should be managed in an intensive care unit. Management is to support the physiology and treat the underlying cause. Advice should be sought from a centre capable of performing liver transplantation. Should recovery seem unlikely, liver transplantation is a viable treatment option in some cases.

Comparative effectiveness of two doses versus three doses of hepatitis A vaccine in human immunodeficiency virus-infected and -uninfected men who have sex with men

The purpose of this prospective cohort study was to compare the serologic response between human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) receiving two and three doses of hepatitis A virus (HAV) vaccine and HIV-uninfected MSM receiving two doses of HAV vaccine. Between June 2009 and December 2010, 582 MSM aged 18 to 40 years who were seronegative for HAV were enrolled in the study. HIV-infected MSM received either two doses of HAV vaccine (1,440 enzyme-linked immunosorbent assay units) (n = 140) with the second dose given at week 24 or three doses (n = 225) with the second and third dose given at weeks 4 and 24, respectively, while HIV-uninfected MSM (n = 217) received two doses. The primary endpoint was seroconversion at week 48. The geometric mean concentration (GMC) of anti-HAV antibody was determined at weeks 48 and 72. At week 48, the seroconversion rate was 75.7%, 77.8%, and 88.5% in intention-to-treat analysis for two-dose HIV-infected, three-dose HIV-infected, and two-dose HIV-uninfected MSM, respectively. The GMC of anti-HAV antibody at week 48 for three-dose HIV-infected MSM (2.29 ± 0.73 log10 mIU/mL) was significantly higher than that for two-dose HIV-infected MSM (1.94 ± 0.66; P < 0.01), but was lower than HIV-uninfected MSM (2.49 ± 0.42; P < 0.01). Multivariate analysis revealed higher CD4 counts (adjusted odds ratio [AOR] for per 50 cells/μL increase, 1.13; 95% confidence interval [CI], 1.05-1.21) and undetectable plasma HIV RNA load (AOR, 1.90; 95% CI, 1.10-3.28) before HAV vaccination were predictive of seroconversion in HIV-infected patients.

CONCLUSION

Serologic response rate to three and two doses of HAV vaccine was similar in HIV-infected MSM, which was lower than that in HIV-uninfected MSM receiving two doses. HAV vaccination in HIV-infected patients with a higher CD4 count and suppression of HIV replication increased the seroconversion rate.

A case of severe acute hepatitis a complicated with pure red cell aplasia

Hepatitis A is typically a self-limited acute illness that does not progress to chronic hepatitis. In rare cases, acute hepatitis A can be associated with serious complications (such as fulminant hepatitis or acute kidney injury) and may result in death or liver transplantation. Pure red cell aplasia (PRCA) is a rare hematologic disorder characterized by anemia, reticulocytopenia in the blood, and isolated erythroblastopenia with normal granulopoiesis and megakaryopoiesis in the bone marrow. PRCA is a rare hematopoietic complication of acute viral hepatitis, and few cases associated with hepatitis A virus infection have been reported. Recently, we experienced a case of severe hepatitis A complicated by fulminant hepatitis and acute kidney injury followed by PRCA which showed a favorable response to oral corticosteroids.

Short-term assessment of toxicological aspects, oxidative and inflammatory response to dietary melon superoxide dismutase in rats

The protective effects of SODB, a gastro-resistant encapsulated melon superoxide dismutase, on haematological and biochemical parameters and inflammatory and oxidative status, were evaluated in the blood and liver tissue. The study consisted in a 28-day experiment on rats supplemented with three doses (10, 40 and 160USOD/day) of SODB-M, SODB-D or SODB-S, different depending on the nature of the coating (palm oil, shellac or gum Arabic respectively). No mortality, abnormal clinical signs, behavioural changes or macroscopic findings were observed whatever the groups. Haematological parameters (total red blood cell count, haemoglobin content, haematocrit, red cell indices, white blood cell count and platelets count) were not modified in SODB treated-groups. No marked change was recorded in biochemical parameters (plasma urea, creatinine, lipids, electrolytes, bilirubin, transaminases and gamma-glutamyl transferase). The liver endogenous antioxidant enzymes (copper/zinc and manganese superoxide dismutase) expressions were significantly increased in the rats receiving the highest dose of SODB (160USOD/day) whatever the coating. Moreover, interleukin-6, a marker of inflammation, was significantly decreased in these high dose-treated-groups. The present study indicates that dietary supplementation of SODB on rats has no harmful side effects and could be beneficial especially at high doses.

Does chronic hepatitis B infection affect the clinical course of acute hepatitis A?

The impact of chronic hepatitis B on the clinical outcome of acute hepatitis A remains controversial. The aim of present study was to evaluate the clinical characteristics of acute hepatitis A in cases with underlying chronic hepatitis B compared to cases of acute hepatitis A alone. Data on 758 patients with acute hepatitis A admitted at two university-affiliated hospitals were reviewed. Patients were classified into three groups: group A, patients with both acute hepatitis A and underlying chronic hepatitis B (n = 27); group B, patients infected by acute hepatitis A alone whose sexes and ages were matched with patients in group A (n  = 54); and group C, patients with acute hepatitis A alone (n = 731). None of the demographic features of group A were significantly different from those of group B or C, except for the proportion of males and body weight, which differed from group C. When comparing to group B, clinical symptoms were more frequent, and higher total bilirubin and lower albumin levels were observed in group A. When comparing to group C, the albumin levels were lower in group A. There were no differences in the duration of hospital stay, occurrence of acute kidney injury, acute liver failure, prolonged cholestasis, or relapsing hepatitis. This study revealed that clinical symptoms and laboratory findings were less favorable for patients with acute hepatitis A and chronic hepatitis B compared to those with acute hepatitis A alone. However, there were no differences in fatal outcomes or serious complications.

Hepatitis in the elderly: still a scourge

Liver disease presents with classic symptoms: fatigue, anorexia that progresses to nausea and vomiting, muscle and joint pain, and jaundice. Its most common cause is viral infection (hepatitis) with one of the hepatotropic hepatitis viruses. Although all types of hepatitis cause liver disease, their modes of transmission differ, and treatment may or may not be an option. In all types of hepatitis, people older than 65 years of age tend to develop more severe disease than those who are younger. Hepatitis A is rare in the United States, usually resolves completely with rest and supportive care, and there is no drug treatment. The Food and Drug Administration has approved several medications for hepatitis B, although comorbidities in the elderly may preclude their use. Hepatitis C is generally treated with interferon alpha and ribavirin in patients who can tolerate these agents. Chronic hepatitis D infection is more aggressive than chronic hepatitis B infection, leading to cirrhosis within two years in 10% to 15% of patients. Treatment with interferon for at least one year is recommended, but may not help. Hepatitis E virus infection-typically associated with large waterborne epidemics and endemic in Asia, Africa, and Mexico-is poorly understood and reported only sporadically in the United States. Consultant pharmacists can provide invaluable input concerning management of patients with hepatitis since few guidelines are available. Treatment is complex and often associated with side effects, and it is costly to treat. Complete adherence is critical. Residents, their families, and long-term care staff will need education and support in treating these patients. Pharmacist involvement is especially important as newly approved agents become available; side effects can cause clinicians and patients to abandon treatment.

Pleural effusion - An unusual cause

Hepatitis A (HAV) infection is one of the most common forms of hepatitis in the paediatric age group in developing countries. It is usually self-limiting and rarely accompanied by extra hepatic complication. In this article, we report two children with hepatitis A who had associated issues of pleural effusion and ascites. Both issues improved with resolution of hepatitis after symptomatic treatment. Although uncommon, extra hepatic manifestations can occur with hepatitis A. However, they resolve completely. Paediatricians in developing countries should be aware of this rare association to avoid unnecessary investigations.

Corticosteroid treatment of pure red cell aplasia in a patient with hepatitis A

Secondary pure red cell aplasia (PRCA), as an extrahepatic manifestation of hepatitis A virus infection, has been reported on rare occasions. We report herein an unusual case of hepatitis A complicated by PRCA. In addition, we reviewed nine cases reported in the English literature. Our case of nonfulminant hepatitis A complicated by PRCA and hemolytic anemia was successfully treated with initial transfusion and corticosteroid therapy for 18 weeks. The patient's hematologic abnormalities and liver function tests re-normalized completely. We review clinical features and effective therapeutic strategies for this disease entity.

Viral hepatitis in the elderly

As life expectancy continues to rise, elderly adults represent a rapidly growing proportion of the population. The likelihood of complications of acute and chronic liver disease and overall mortality are higher in elderly populations. Several physiological changes associated with aging, greater prevalence of co-morbid conditions, and cumulative exposure to hepatotropic viruses and environmental hepatotoxins may contribute to worse outcomes of viral hepatitis in the elderly. Although pharmacotherapy for hepatitis B and C continues to evolve, the efficacy, tolerability, and side effects of these agents have not been studied extensively in elderly adults. Immunization against hepatitis A and B in naïve elderly adults is an important public health intervention that needs to be revised and broadened.

Epidemiological changes in hepatitis A in Korea: increasing age and its effect on clinical outcomes

Korea has recently experienced an increasing number of acute hepatitis A cases. We investigated the dynamics of hepatitis A and changes in the mean age of patients in a hospital in Seoul, Korea. Mean age increased consistently from 19 years in 1996 to 30 years in 2009 (P < 0·0001). Between two acute hepatitis A outbreaks in 1998–1999 and in 2008–2009, mean age increased from 23 to 30 years (P < 0·001). However, the hepatitis A clinical outcomes were similar between the outbreaks. Duration of hospital stay, creatinine level and prothrombin time did not differ. Throughout the study period, individuals born in the 1970s and 1980s comprised the largest proportion (84%) of patients. As this susceptible generation ages, the mean age of hepatitis A patients in Korea will increase consistently. However, at present, the impact of increasing age on clinical outcomes is not apparent.

Fatal outbreaks of jaundice in pregnancy and the epidemic history of hepatitis E

Space-time clustering of people who fall acutely ill with jaundice, then slip into coma and death, is an alarming phenomenon, more markedly so when the victims are mostly or exclusively pregnant. Documentation of the peculiar, fatal predisposition of pregnant women during outbreaks of jaundice identifies hepatitis E and enables construction of its epidemic history. Between the last decade of the 18th century and the early decades of the 20th century, hepatitis E-like outbreaks were reported mainly from Western Europe and several of its colonies. During the latter half of the 20th century, reports of these epidemics, including those that became serologically confirmed as hepatitis E, emanated from, first, the eastern and southern Mediterranean littoral and, thereafter, Southern and Central Asia, Eastern Europe, and the rest of Africa. The dispersal has been accompanied by a trend towards more frequent and larger-scale occurrences. Epidemic and endemic hepatitis E still beset people inhabiting Asia and Africa, especially pregnant women and their fetuses and infants. Their relief necessitates not only accelerated access to potable water and sanitation but also vaccination against hepatitis E.

Factors influencing the severity of acute viral hepatitis A

Background/Aims

Most patients with acute viral hepatitis A have a favorable course, but a few of them suffer from severe forms of hepatitis such as fulminant hepatitis. This study was carried out to identify the factors influencing the severity of acute viral hepatitis A.

Methods

We retrospectively reviewed the medical records of 713 patients with acute hepatitis A, who were divided into two groups: severe hepatitis A (N=87) and non-severe hepatitis A (N=626). Severe hepatitis was defined as fulminant hepatitis or prolongation of prothrombin time (INR≥1.5). Clinical variables were compared between the two groups.

Results

The incidence of fulminant hepatitis was 1.4% (10/713) in patients with acute hepatitis A. Thirty-three (4.6%) cases exhibited HBsAg positivity. In multivariate analyses, significant alcohol intake and the presence of HBsAg were significant predictive factors of fulminant hepatitis A, and significant alcohol intake and age were significant predictive factors of severe hepatitis A. HBeAg and HBV-DNA status did not affect the clinical course of hepatitis A in chronic hepatitis B carriers.

Conclusions

While most patients with acute hepatitis A have an uncomplicated clinical course, our data suggest that a more-severe clinical course is correlated with being older, significant alcohol intake, and chronic hepatitis-B-virus infection.

Hepatitis A viral load in relation to severity of the infection

A correlation between hepatitis A virus (HAV) genomes and the clinical severity of hepatitis A has not been established. The viral load in sera of hepatitis A patients was examined to determine the possible association between hepatitis A severity and HAV replication. One hundred sixty-four serum samples from 91 Japanese patients with sporadic hepatitis A, comprising 11 patients with fulminant hepatitis, 10 with severe acute hepatitis, and 70 with self-limited acute hepatitis, were tested for HAV RNA. The sera included 83 serial samples from 20 patients. Viral load was measured by real-time RT-PCR. The detection rates of HAV RNA from fulminant, severe acute, and acute hepatitis were 10/11 (91%), 10/10 (100%), and 55/70 (79%), respectively. Mean values of HAV RNA at admission were 3.48 ± 1.30 logcopies/ml in fulminant, 4.19 ± 1.03 in severe acute, and 2.65 ± 1.64 in acute hepatitis. Patients with severe infection such as fulminant hepatitis and severe acute hepatitis had higher initial viral load than patients with less severe infection (P < 0.001). Viremia persisted for 14.2 ± 5.8 days in patients with severe infection and 21.4 ± 10.6 days in those with acute hepatitis after clinical onset (P = 0.19). HAV RNA was detectable quantitatively in the majority of the sera of hepatitis A cases during the early convalescent phase by real-time PCR. Higher initial viral replication was found in severely infected patients. An excessive host immune response might follow, reducing the viral load rapidly as a result of the destruction of large numbers of HAV-infected hepatocytes, and in turn severe disease might be induced.