What did we learn from the Shanghai hepatitis A epidemic?

Vaccination in Patients with Liver Cirrhosis: A Neglected Topic

Patients with liver cirrhosis, due to their weakened innate and adaptive immunity, are more prone to frequent and severe vaccine-preventable infections. Moreover, impaired adaptive immunity results in a limited antibody response to vaccines. Despite this suboptimal antibody response, vaccines have proven to be very effective in reducing severe outcomes and deaths in these patients. In the Western world, regulatory authorities and scientific liver societies (e.g., AASLD and EASL) have recommended vaccinations for cirrhotic patients. However, despite these strong recommendations, vaccine coverage remains suboptimal. Improving vaccine effectiveness and safety information, providing comprehensive counseling to patients, fact-checking to combat fake news and disinformation and removing barriers to vaccination for disadvantaged individuals may help overcome the low coverage rate. In view of this, vaccines should be administered early in the course of chronic liver diseases, as their efficacy declines with the increasing severity of the disease.

Hepatitis A hospitalisations in the United States and risk factors for inpatient mortality: A nationwide population study, 1998-2020

Hepatitis A virus infections in the United States have been declining; however, recent widespread outbreaks have brought the disease back into the spotlight. We aim to describe the epidemiology of hepatitis A hospitalisations from 1998 to 2020 in the United States and investigate risk factors for inpatient mortality. We utilised the National Inpatient Sample database and identified hepatitis A-related hospitalisations using ICD-9 and ICD-10 diagnosis codes. Demographic and clinical data including death, coinfections, comorbidities and pregnancy status were extracted. Data were analysed by logistic and Poisson regression. We identified a total of 213,681 hepatitis A-related hospitalisations between 1998 and 2020, with hospitalisation rates ranging between 22.4 per 1,000,000 and 62.9 per 1,000,000. Between 1998 and 2015, the hospitalisation rate for hepatitis A was decreasing (IRR = 0.98; 95% CI: 0.97-0.98; p < .001); however, between 2015 and 2020, it increased overall (IRR = 1.22; 95% CI: 1.21-1.23; p < .001). The overall inpatient mortality rate was 2.7%. Age ≥55 years (OR = 1.84; 95% CI: 1.41-2.40; p < .001), alcoholic cirrhosis (OR = 2.53; 95% CI: 1.64-3.90; p < .001), ascites (OR = 2.65; 95% CI: 1.86-3.78; p < .001), hepatorenal syndrome (OR = 9.04; 95% CI: 5.93-13.80; p < .001), heart failure (OR = 1.76; 95% CI: 1.29-2.39; p < .001), pulmonary hypertension (OR = 2.02; 95% CI: 1.28-3.19; p = .003) and malignant neoplasm (OR = 1.75; 95% CI: 1.25-2.45; p = .001) were associated with increased odds of mortality. Tobacco use disorder (OR = 0.52; 95% CI: 0.38-0.70; p < .001) was associated with decreased odds of mortality. None of the hepatitis A-associated hospitalisations involving pregnant women resulted in death. Hepatitis A hospitalisations initially declined but increased rapidly after 2015. Certain risk factors can be used to predict prognosis of hospitalised patients.

Consensus recommendations on the management of hepatitis C in Australia's prisons

INTRODUCTION

Prison settings represent the highest concentration of prevalent hepatitis C cases in Australia due to the high rates of incarceration among people who inject drugs. Highly effective direct-acting antiviral (DAA) therapies for hepatitis C virus (HCV) infection are available to people incarcerated in Australian prisons. However, multiple challenges to health care implementation in the prison sector present barriers to people in prison reliably accessing hepatitis C testing, treatment, and prevention measures.

MAIN RECOMMENDATIONS

This Consensus statement highlights important considerations for the management of hepatitis C in Australian prisons. High coverage testing, scale-up of streamlined DAA treatment pathways, improved coverage of opioid agonist therapy, and implementation and evaluation of regulated provision of prison needle and syringe programs to reduce HCV infection and reinfection are needed.

CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT

The recommendations set current best practice standards in hepatitis C diagnosis, treatment and prevention in the Australian prison sector based on available evidence. Prison-based health services should strive to simplify and improve efficiency in the provision of the hepatitis C care cascade, including strategies such as universal opt-out testing, point-of-care testing, simplified assessment protocols, and earlier confirmation of cure. Optimising hepatitis C management in prisons is essential to prevent long term adverse outcomes for a marginalised population living with HCV. Scale-up of testing and treatment in prisons will make a major contribution towards Australia's efforts to eliminate hepatitis C as a public health threat by 2030.

Safety of concomitant administration of inactivated hepatitis A vaccine with other vaccines in children under 16 years old in post-marketing surveillance

BACKGROUND

Concomitant administration refers to the receipt of two or more vaccines during a single healthcare encounter, which is an efficient way to increase vaccination coverage in children. However, the post-marketing safety studies of concomitant administration are scarce. Inactivated hepatitis A vaccine (Healive®) has been used widely in China and other countries for more than a decade. We aimed to explore the safety of Healive® co-administered with other vaccines compared to Healive® alone in children under 16 years old.

METHODS

We retrieved Adverse Events Following Immunization (AEFI) cases and vaccination doses of Healive® during 2020-2021 in Shanghai, China. The AEFI cases were divided into concomitant administration group and Healive® alone group. We used administrative data on vaccine doses as denominators to calculate and compare crude reporting rates between groups. We also compared baseline gender and age distribution, clinical diagnoses, and time interval from vaccination to onset of symptoms between groups.

RESULTS

A total 319,247 doses of inactivated hepatitis A vaccine (Healive®) were used and 1,020 AEFI cases (319.50 per million doses) associated with Healive® were reported during 2020-2021 in Shanghai. There were 259,346 doses concomitantly administered with other vaccines and 830 AEFI cases (320.04 per million doses) were reported. There were 59,901 doses of Healive® that vaccinated alone, with 190 AEFI cases (317.19 per million doses). There was only one case with serious AEFI in concomitant administration group, with a rate of 0.39 per million doses. Reported rates of AEFI cases were similar between groups in general (p > 0.05).

CONCLUSION

Concomitant administration of inactivated hepatitis A vaccine (Healive®) with other vaccines has a similar safe profile as Healive® alone.

A community-wide epidemic of hepatitis A virus genotype IA associated with consumption of shellfish in Yantai, eastern China, January to March 2020

During the first quarter of 2020, a considerable increase in reports of symptomatic hepatitis A cases was noted in Yantai, a coastal city in eastern China. This study aimed to characterize the epidemic and identify the probable source. Serum samples from cases with onsets from 1 January to 31 March 2020 and suspected bivalve mollusk samples from the local seafood market were screened for hepatitis A virus (HAV) RNA by PCR amplification and sequencing of the VP1/2A region. We also analyzed the characteristics and risk exposures of these cases. In total, 110 confirmed cases were notified during the epidemic. Among the 103 cases investigated, the median age was 41 years (range: 25-70 years), and 74 (71.8%) were male. Eighty-eight cases (85.4%) reported having eaten shellfish and 72 (69.9%) specifically oysters. HAV RNA was detected and sequenced successfully in 80.2% (69/86) of the cases, as well as in one oyster out of 20 shellfish samples. Phylogenetic analysis revealed that all isolates belonged to a single genotype IA but presented the co-circulation of five distinct genomic sub-lineages. The oyster-derived HAV strain shared over 98.2% nucleotide identity with all clinical strains obtained during the epidemic, particularly 100% homology with the strains of seven cases. These data indicated that contaminated oyster consumption was probably a common source of this epidemic, although multiple HAV strains were involved. We recommend strengthening shellfish surveillance, changing dietary habits in seafood consumption, and encouraging vaccination for target adults in coastal areas with a high prevalence of hepatitis A.

Epidemiology of liver failure in Asia-Pacific region

The global burden of deaths caused by liver failure is substantial. The Asia-Pacific region is home to more than half of the global population and accounted for 62.6% of global deaths because of liver diseases in 2015. The aetiology of liver failure varies in different countries at different times. Viruses (Hepatitis A, B and E), drugs (herbs and anti-tuberculous drugs), toxins (alcohol use) and autoimmune flares are mainly responsible of majority of liver failure in individuals with normal liver (acute liver failure; ALF); else these may precipitate liver failure in those with chronic liver disease (acute-on-chronic liver failure; ACLF). Concomitant increases in alcohol misuse and metabolic syndrome in recent years are concerning. Ongoing efforts to address liver failure-related morbidity and mortality require accurate contemporary estimates of epidemiology and outcomes. In light of the ever-changing nature of liver disease epidemiology, accurate estimates for the burden of liver failure across the countries are vital for setting clinical, research and policy priorities. In this review, we aimed to describe the current as well as changing epidemiological trends of common liver failure syndromes, ALF and ACLF in the Asia-Pacific region.

Assessing countermeasures during a hepatitis A virus outbreak among men who have sex with men

Background

A hepatitis A epidemic occurred among men who have sex with men (MSM) in Japan in 2017–2018. In this study, we employ a parsimonious mathematical model to epidemiologically investigate the dynamics of infection, aiming to evaluate the effectiveness of campaign-based interventions among MSM to raise awareness of the situation.

Methods

A mathematical model describing a mixture of human-to-human transmission and environmental transmission was fitted to surveillance data. Taking seasonally varying environmental transmission into account, we estimated the reproduction number of hepatitis A virus during the course of epidemic, and, especially, the abrupt decline in this reproduction number following campaign-based interventions.

Results

The reproduction number prior to the countermeasures ranged from 2.6 to 3.1 and then began to decrease following campaign-based interventions. After the first countermeasure, the reproduction number decreased, but the epidemic remained supercritical (i.e., R_t > 1). The value of R_t dropped well below one following the second countermeasure, which used web articles to widely disseminate information about the epidemic risk.

Conclusions

Although the effective reproduction number, R_t, changes because of both intrinsic and extrinsic factors, the timing of the examined countermeasures against hepatitis A in the MSM population was consistent with the abrupt declines observed in R_t. Even without vaccination, the epidemic was brought under control, and risky behaviors may have been changed by the increase in situation awareness reached through web articles.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12976-021-00150-1.

Knockdown of Mitogen-Activated Protein Kinase Kinase 3 Negatively Regulates Hepatitis A Virus Replication

Zinc chloride is known to be effective in combatting hepatitis A virus (HAV) infection, and zinc ions seem to be especially involved in Toll-like receptor (TLR) signaling pathways. In the present study, we examined this involvement in human hepatoma cell lines using a human TLR signaling target RT-PCR array. We also observed that zinc chloride inhibited mitogen-activated protein kinase kinase 3 (MAP2K3) expression, which could downregulate HAV replication in human hepatocytes. It is possible that zinc chloride may inhibit HAV replication in association with its inhibition of MAP2K3. In that regard, this study set out to determine whether MAP2K3 could be considered a modulating factor in the development of the HAV pathogen-associated molecular pattern (PAMP) and its triggering of interferon-β production. Because MAP2K3 seems to play a role in antiviral immunity against HAV infection, it is a promising target for drug development. The inhibition of MAP2K3 may also prevent HAV patients from developing a severe hepatitis A infection.

Need for hepatitis A prevention in patients with chronic liver disease in the changing epidemiological setting of India

The burden of chronic liver disease (CLD) in India is high, particularly among middle-aged men, with nearly 220,000 deaths due to cirrhosis in 2017. CLD increases the risk of infection, severe disease (e.g. hepatitis A virus or HAV superinfection, acute-on-chronic liver failure, fulminant hepatic failure), and mortality. Hence, various countries recommend HAV vaccination for CLD patients. While historic Indian studies showed high seroprevalences of protective HAV antibodies among Indian adults with CLD, the most recent ones found that nearly 7% of CLD patients were susceptible to HAV infection. Studies in healthy individuals have shown that HAV infection in childhood is decreasing in India, resulting in an increasing population of adults susceptible to HAV infection. As patients with CLD are at increased risk of severe HAV infection, now may be the time to recommend HAV vaccination among people with CLD in India.

From hepatitis A to E: A critical review of viral hepatitis

Viral infections affecting the liver have had an important impact on humanity, as they have led to significant morbidity and mortality in patients with acute and chronic infections. Once an unknown etiology, the discovery of the viral agents triggered interest of the scientific community to establish the pathogenesis and diagnostic modalities to identify the affected population. With the rapid scientific and technological advances in the last centuries, controlling and even curing the infections became a possibility, with a large focus on preventive medicine through vaccination. Hence, a comprehensive understanding of hepatitis A, B, C, D and E is required by primary care physicians and gastroenterologists to provide care to these patients. The review article describes the epidemiology, pathogenesis, clinical presentation, diagnostic tools and current medication regimens, with a focus on upcoming treatment options and the role of liver transplantation.

Changing Epidemiology of Hepatitis A in China: Evidence From Three National Serological Surveys and the National Notifiable Disease Reporting System

BACKGROUND AND AIMS

China has conducted surveillance for hepatitis A since 1990, and hepatitis A was highly-to-intermediately endemic in 1992 when a Chinese hepatitis A vaccine (HepA) was licensed and introduced as a family-pay vaccine. In 2008, HepA was introduced into the Expanded Program on Immunization as a free childhood vaccine.

APPROACH AND RESULTS

Three nationally representative surveys conducted in 1992, 2006, and 2014 assessed hepatitis B serology. The 1992 survey included hepatitis A virus (HAV) serology, and we tested sera from the 2006 and 2014 surveys for HAV antibodies. We used surveillance, seroprevalence, and vaccination status data to describe the changing epidemiology of hepatitis A in China from 1990 through 2014. Before HepA licensure, anti-HAV seroprevalence was 60% at 4 years of age, 70% at 10 years, and 90% at 59 years; incidence was 52/100,000 and peaked at 4 years. In 2006, after >10 years of private sector vaccination, HepA coverage was <30% among children <5 years, and incidence was 5.4/100,000 with a peak at 10 years. In 2014, coverage was >90% among children under 5 years; incidence was 1.9/100,000. Individuals born before the national introduction of HepA (1988-2004) had lower anti-HAV seroprevalence than earlier and later birth cohorts.

CONCLUSIONS

The incidence of hepatitis A declined markedly following HepA introduction and improvement of sanitation and hygiene. The emerging epidemiology is consistent with disease-induced immunity having been replaced by vaccine-induced immunity, resulting in a low incidence of hepatitis A. Catch-up HepA campaigns to close the immunity gap among the 1998-2004 birth cohorts should be considered.

Food safety in fisheries: Application of One Health approach

Fisheries comprise the fastest growing sector meeting the global protein requirements. Being an affordable enterprise, it is considered a safe source of food and the muscles of healthy fishes are almost sterile. However, a multitude of hazards (biological, chemical, and environmental) can be introduced into aquaculture throughout the production and supply chain. Also, it can originate from unsuitable farming practices, environmental pollution, and socio-cultural habits prevailing in various regions. Hence, with an increasing global population and demands for aquacultural products, assessment and regulation of food safety concerns are becoming significantly evident. Ensuring safe, secure, affordable, and quality food for all in a global context is pragmatically difficult. In this context, it is quite imperative to understand the ecology and dynamics of these hazards throughout the entire production chain in a One Health approach. Here, we discuss the issues and challenges faced in the fisheries sector as a whole and the need for a One Health approach to overcome such hurdles.

The History of Hepatitis A

Watch an interview with the author.

Natural Host-Environmental Media-Human: A New Potential Pathway of COVID-19 Outbreak

Identifying the first infected case (patient zero) is key in tracing the origin of a virus; however, doing so is extremely challenging. Patient zero for coronavirus disease 2019 (COVID-19) is likely to be permanently unknown. Here, we propose a new viral transmission route by focusing on the environmental media containing viruses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or RaTG3-related bat-borne coronavirus (Bat-CoV), which we term the "environmental quasi-host." We reason that the environmental quasi-host is likely to be a key node in helping recognize the origin of SARS-CoV-2; thus, SARS-CoV-2 might be transmitted along the route of natural host-environmental media-human. Reflecting upon viral outbreaks in the history of humanity, we realize that many epidemic events are caused by direct contact between humans and environmental media containing infectious viruses. Indeed, contacts between humans and environmental quasi-hosts are greatly increasing as the space of human activity incrementally overlaps with animals' living spaces, due to the rapid development and population growth of human society. Moreover, viruses can survive for a long time in environmental media. Therefore, we propose a new potential mechanism to trace the origin of the COVID-19 outbreak.

Co-Occurrence of Hepatitis A Infection and Chronic Liver Disease

Hepatitis A virus (HAV) infection occasionally leads to a critical condition in patients with or without chronic liver diseases. Acute-on-chronic liver disease includes acute-on-chronic liver failure (ACLF) and non-ACLF. In this review, we searched the literature concerning the association between HAV infection and chronic liver diseases in PubMed. Chronic liver diseases, such as metabolic associated fatty liver disease and alcoholic liver disease, coinfection with other viruses, and host genetic factors may be associated with severe hepatitis A. It is important to understand these conditions and mechanisms. There may be no etiological correlation between liver failure and HAV infection, but there is an association between the level of chronic liver damage and the severity of acute-on-chronic liver disease. While the application of an HAV vaccination is important for preventing HAV infection, the development of antivirals against HAV may be important for preventing the development of ACLF with HAV infection as an acute insult. The latter is all the more urgent given that the lives of patients with HAV infection and a chronic liver disease of another etiology may be at immediate risk.

Public Awareness, Individual Prevention Practice, and Psychological Effect at the Beginning of the COVID-19 Outbreak in China

BACKGROUND

The COVID-19 has spread to more than 200 countries and territories. But less is known about the knowledge, protection behavior and anxiety regarding the outbreak among the general population.

METHODS

A cross-sectional, population-based online survey was conducted in China and abroad from January 28 to February 1, 2020. Socio-demographic information was collected and knowledge scores, practice scores, anxiety scores and perceived risk were calculated. General linear model and binary logistic regression were used to identify possible associations.

RESULTS

We included 9,764 individuals in this study, and 156 (1.6%) were from Hubei Province. The average knowledge score was 4.7 (standard deviation, 1.0) (scored on a 6-point scale); 96.1% maintained hand hygiene, and 90.3% of participants had varying levels of anxiety. People in Hubei Province were the most anxious, followed by those in Beijing and Shanghai. People who had experienced risk behaviors did not pay more attention to wearing masks and hand hygiene.

CONCLUSIONS

The public had high awareness on knowledge of COVID-19 outbreak, and a high proportion of people practiced good hand hygiene behavior. Many people claimed anxiety, especially in heavily affected areas during pandemic, suggesting the importance of closing the gap between risk awareness and good practice and conduct psychological counseling to public and patients.

Hepatitis A vaccination

Hepatitis A is an important public health issue worldwide. Hepatitis A vaccine (HepA) was first licensed in 1992. Both inactivated HepA (HepA-I) and live attenuated HepA (HepA-L) are highly immunogenic and well tolerated, and immune protection postvaccination can persist for at least 20 y. HepA is effective for both preexposure and postexposure prophylaxis, especially among children and young adults. The strategy of HepA vaccination varies in different countries and mainly includes vaccination among high-risk populations, regional childhood vaccination and universal childhood vaccination. The incidence of hepatitis A has decreased greatly in many countries in the last 30 y, but hepatitis A outbreaks frequently occur among high-risk populations and those who have not been covered by universal child vaccination programs in recent years. Disease surveillance and serosurveys are suggested to clarify the shift in the epidemiology of hepatitis A. The long-term persistence of immune protection after one dose of HepA should be further studied, as well as the cost-effective evaluation of different strategies of HepA vaccination. Based on this evidence, the recommendation on HepA vaccination should be put forward scientifically and updated in a timely and well-implemented manner.

Prevention of Hepatitis A Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices, 2020

HEPATITIS A IS A VACCINE-PREVENTABLE, COMMUNICABLE DISEASE OF THE LIVER CAUSED BY THE HEPATITIS A VIRUS (HAV). THE INFECTION IS TRANSMITTED VIA THE FECAL-ORAL ROUTE, USUALLY FROM DIRECT PERSON-TO-PERSON CONTACT OR CONSUMPTION OF CONTAMINATED FOOD OR WATER. HEPATITIS A IS AN ACUTE, SELF-LIMITED DISEASE THAT DOES NOT RESULT IN CHRONIC INFECTION. HAV ANTIBODIES (IMMUNOGLOBULIN G [IGG] ANTI-HAV) PRODUCED IN RESPONSE TO HAV INFECTION PERSIST FOR LIFE AND PROTECT AGAINST REINFECTION; IGG ANTI-HAV PRODUCED AFTER VACCINATION CONFER LONG-TERM IMMUNITY. THIS REPORT SUPPLANTS AND SUMMARIZES PREVIOUSLY PUBLISHED RECOMMENDATIONS FROM THE ADVISORY COMMITTEE ON IMMUNIZATION PRACTICES (ACIP) REGARDING THE PREVENTION OF HAV INFECTION IN THE UNITED STATES. ACIP RECOMMENDS ROUTINE VACCINATION OF CHILDREN AGED 12-23 MONTHS AND CATCH-UP VACCINATION FOR CHILDREN AND ADOLESCENTS AGED 2-18 YEARS WHO HAVE NOT PREVIOUSLY RECEIVED HEPATITIS A (HEPA) VACCINE AT ANY AGE. ACIP RECOMMENDS HEPA VACCINATION FOR ADULTS AT RISK FOR HAV INFECTION OR SEVERE DISEASE FROM HAV INFECTION AND FOR ADULTS REQUESTING PROTECTION AGAINST HAV WITHOUT ACKNOWLEDGMENT OF A RISK FACTOR. THESE RECOMMENDATIONS ALSO PROVIDE GUIDANCE FOR VACCINATION BEFORE TRAVEL, FOR POSTEXPOSURE PROPHYLAXIS, IN SETTINGS PROVIDING SERVICES TO ADULTS, AND DURING OUTBREAKS.

Culture, eating behavior, and infectious disease control and prevention

Humans need to obtain nutrients from foods for survival and health. Culture and belief play important roles in food selection and intake. Throughout human history, dietary factor has been one of the important factors inducing and causing outbreaks of infectious diseases. If unhealthy eating behavior, like eating raw/undercooked food or meat and products from wild animals, are not abandoned, foodborne infectious diseases will remain an important risk factor of outbreaks and epidemics. The misconception of dietary culture is one of the important factors that triggers unhealthy eating behavior. Therefore, it is vital to change people’s conceptions and knowledge about what is healthy to eat, in order to completely eliminate unhealthy eating behavior and prevent the recurrence of foodborne infectious diseases. Meanwhile, many factors such as family, society, region, and religion should be involved in.

Perspectives on Acute Hepatitis A Control in Korea

Until 1995, the incidence of symptomatic acute hepatitis A was minimal and there were no cases of national outbreak in Korea. However, there was a nationwide outbreak of hepatitis A that peaked in 2009. In 2019, a total of 10,083 cases of acute hepatitis A were reported for seven months of the year according to the Korea Center for Disease Control and Prevention. This may be attributed to the proportion of susceptible subjects in the Korean population, as about 10 years have passed since herd immunity was induced by the epidemic occurring during the late 2000s. Recent studies have shown that the rate of seropositivity for anti-hepatitis A virus antibodies (anti-HAV) is the lowest in adults in their 20s and has not changed much over the past 10 years, and seropositivity of anti-HAV in adults in their 30s has continued to decline from 69.6% in 2005 to 32.4% in 2014. Most young adults who have not yet experienced hepatitis A and are not vaccinated are vulnerable to hepatitis A infection. This year's epidemic of hepatitis A is a predictable outcome for vulnerable populations. Therefore, effective acute hepatitis A control and prevention strategies are needed, particularly for those in their 20s and 30s.

Burden of liver diseases in the world

Liver disease accounts for approximately 2 million deaths per year worldwide, 1 million due to complications of cirrhosis and 1million due to viral hepatitis and hepatocellular carcinoma. Cirrhosis is currently the 11th most common cause of death globally and liver cancer is the 16th leading cause of death; combined, they account for 3.5% of all deaths worldwide. Cirrhosis is within the top 20 causes of disability-adjusted life years and years of life lost, accounting for 1.6% and 2.1% of the worldwide burden. About 2 billion people consume alcohol worldwide and upwards of 75 million are diagnosed with alcohol-use disorders and are at risk of alcohol-associated liver disease. Approximately 2 billion adults are obese or overweight and over 400 million have diabetes; both of which are risk factors for non-alcoholic fatty liver disease and hepatocellular carcinoma. The global prevalence of viral hepatitis remains high, while drug-induced liver injury continues to increase as a major cause of acute hepatitis. Liver transplantation is the second most common solid organ transplantation, yet less than 10% of global transplantation needs are met at current rates. Though these numbers are sobering, they highlight an important opportunity to improve public health given that most causes of liver diseases are preventable.

Natural History, Clinical Manifestations, and Pathogenesis of Hepatitis A

Hepatitis A virus (HAV) is transmitted by the fecal-oral route and is a major cause of acute viral hepatitis. The clinical manifestations of HAV infection range from asymptomatic infection to acute liver failure (ALF), but do not include progression to chronic hepatitis. Risk factors for severe acute hepatitis A are older age (>40 years) and preexisting liver disease. Some patients may show atypical clinical features such as relapsing hepatitis, prolonged cholestasis, or extrahepatic manifestations. Almost all hepatitis A patients spontaneously recover with supportive care. However, in the case of ALF (<1%), intensive care and urgent decision on liver transplantation are required. Liver injury during hepatitis A is not directly caused by HAV but is known to be caused by immune-mediated mechanisms. In this review, the natural history and clinical manifestations of hepatitis A are described. In addition, mechanisms of immunopathogenesis in hepatitis A are discussed.

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 A virus genotype IA-infected patient with marked elevation of aspartate aminotransferase levels

We describe a case of acute liver failure (ALF) without hepatic encephalopathy with marked elevation of aminotransferase due to hepatitis A, according to the revised Japanese criteria of ALF. This liver biopsy of the patient showed compatible to acute viral hepatitis and she immediately recovered without intensive care. She had no comorbid disorders. Of interest, phylogenetic tree analysis using almost complete genomes of hepatitis A virus (HAV) demonstrated that the HAV isolate from her belonged to the HAV subgenotype IA strain and was similar to the HAJFF-Kan12 strain (99% nucleotide identity) or FH1 strain (98% nucleotide identity), which is associated with severe or fulminant hepatitis A. Careful interpretation of the association between HAV genome variations and severity of hepatitis A is needed and the mechanism of the severe hepatitis should be explored.

Shellfish-Associated Enteric Virus Illness: Virus Localization, Disease Outbreaks and Prevention

Numerous outbreaks of shellfish-borne enteric virus illness have been reported worldwide. Most notable among the outbreaks are those caused by NoV and HAV. Lessons learned from outbreak investigations indicate that most outbreaks are preventable. Anthropogenic sources of contamination will continue to invade shellfish growing waters. Shellfish, by their very nature, will continue to bioconcentrate these contaminants, including enteric viruses. There is no quick fix for enteric virus contamination of shellfish; however, vigilance on behalf of the industry, regulatory agencies, and the consumer could substantially reduce the incidence of illness. Enhanced monitoring in all areas of shellfish production, harvesting, distribution, and processing would help to reduce viral illnesses. Pollution abatement and improved hygienic practices on behalf of the industry and consumers are needed. Improved analytical techniques for the detection of enteric viruses in shellfish will lead to enhanced shellfish safety and better protection for the consumer and the industry. Better reporting and epidemiological follow-up of outbreaks are keys to reducing the transmission of foodborne viral infections. It is anticipated that recent advances in analytical techniques, particularly for NoV, will lead to better monitoring capabilities for food and water and a reduction in the incidence of enteric virus illness among shellfish consumers.

Comparison of the safety and immunogenicity of live attenuated and inactivated hepatitis A vaccine in healthy Chinese children aged 18 months to 16 years: results from a randomized, parallel controlled, phase IV study

For large-scale immunization of children with hepatitis A (HA) vaccines in China, accurately designed studies comparing the safety and immunogenicity of the live attenuated HA vaccine (HA-L) and inactivated HA vaccine (HA-I) are necessary. A randomized, parallel controlled, phase IV clinical trial was conducted with 6000 healthy children aged 18 months to 16 years. HA-L or HA-I was administered at a ratio of 1: 1 to randomized selected participants. The safety and immunogenicity were evaluated. Both HA-L and HA-I were well tolerated by all participants. The immunogenicity results showed that the seroconversion rates (HA-L versus HA-I: 98.0% versus 100%, respectively, p >0.05), and geometric mean concentrations in participants negative for antibodies against HA virus IgG (anti-HAV IgG) before vaccination did not differ significantly between the two types of vaccines (HA-L versus HA-I first dose: 898.9 versus 886.2 mIU/mL, respectively, p >0.05). After administration of the booster dose of HA-I, the geometric mean concentrations of anti-HAV IgG (HA-I booster dose: 2591.2 mIU/mL) was higher than that after the first dose (p <0.05) and that reported in participants administered HA-L (p <0.05). Additionally, 12 (25%) of the 48 randomized selected participants who received HA-L tested positive for HA antigen in stool samples. Hence, both HA-L and HA-I could provide acceptable immunogenicity in children. The effects of long-term immunogenicity after natural exposure to wild-type HA virus and the possibility of mutational shifts of the live vaccine virus in the field need to be studied in more detail.

Vaccinating Adult Patients with Cirrhosis: Trends over a Decade in the United States

Introduction. The progression of chronic liver disease to cirrhosis involves both innate and adaptive immune system dysfunction resulting in increased risk of infectious complications. Vaccinations against pneumococcus, hepatitis A virus (HAV), and hepatitis B virus (HBV) are well tolerated and effective in disease prevention and reduction in morbidity and mortality. Prior studies assessing vaccination rates in patients with cirrhosis have specific limitations and to date no study has provided a comprehensive evaluation of vaccination rates in patients with cirrhosis in the United States. Aim. This study assessed vaccination rates for pneumococcus, HAV, and HBV in patients with cirrhosis. Results. Overall 59.7% of patients with cirrhosis received at least 1 vaccination during the study period. Vaccination rates within the same or following year of cirrhosis diagnosis were 19.9%, 7.7%, and 11.0% against pneumococcus, HAV, and HBV, respectively. Trend analysis revealed significant increases in vaccination rates for pneumococcus in all patients with cirrhosis and within subgroups based on age, gender, and presence of concomitant diabetes. Conclusion. The study demonstrated that vaccination rates in patients with cirrhosis remain suboptimal. Ultimately, the use of electronic medical record (EMR) reminders improved communication between healthcare professionals and public health programs to increase awareness are fundamental to reducing morbidity, mortality, and health-care related costs of vaccine preventable diseases in patients with cirrhosis.

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.

Epidemiology and prevention of hepatitis A in travelers

BACKGROUND

Hepatitis A is the second most common vaccine-preventable travel-associated infectious disease and hepatitis A virus (HAV) is the most common cause of viral hepatitis. The incidence of infection is closely related to sanitary conditions and the level of economic development.

METHODS

We evaluated HAV incidence, infection-related risk factors, and HAV vaccination rates in international travelers through retrospective analyses using major databases, such as CENTRAL, MEDLINE, EMBASE, and the current literature describing epidemiological data for HAV infection in recent years.

RESULTS AND CONCLUSIONS

We found that the incidence of HAV infection in developed countries is very low. As international travel increases, the incidence of hepatitis A among travelers remains high and likely leads to regional outbreaks. Travelers should visit the Centers for Disease Control and Prevention website or Infectious Disease Prevention Center of their countries to learn about the incidence of infectious diseases associated with their destination before going abroad to determine if they should be vaccinated.

Hepatitis A vaccine should receive priority in National Immunization Schedule in India

Hepatitis A is an acute, usually self-limiting infection of the liver caused by a virus known as hepatitis A virus (HAV). Humans are the only reservoir of the virus; transmission occurs primarily through the fecal-oral route and is closely associated with poor sanitary conditions. The virus has a worldwide distribution and causes about 1.5 million cases of clinical hepatitis each year. The risk of developing symptomatic illness following HAV infection is directly correlated with age. As many 85% of children below 2 y and 50% of those between 2-5 y infected with HAV are anicteric, and among older children and adults, infection usually causes clinical disease, with jaundice occurring in more than 70% of cases. The infection is usually self-limiting with occasional fulminant hepatic failure and mortality. In most developing countries in Asia and Africa, hepatitis A is highly endemic such that a large proportion of the population acquires immunity through asymptomatic infection early in life. HAV is endemic in India; most of the population is infected asymptomatically in early childhood with life-long immunity. Several outbreaks of hepatitis A in various parts of India have been recorded in the past decade such that anti-HAV positivity varied from 26 to 85%. Almost 50% of children of ages 1-5 y were found to be susceptible to HAV. Any one of the licensed vaccines may be used since all have nearly similar efficacy and safety profiles (except for post-exposure prophylaxis / immunocompromised patients, where only inactivated vaccines may be used). Two doses 6 mo apart are recommended for all vaccines. All Hepatitis A vaccines are licensed for use in children aged 1 y or older. However in the Indian scenario, it is preferable to administer the vaccines at age 18 mo or more when maternal antibodies have completely declined. Vaccination at this age is preferable to later since it is easier to integrate with the existing schedule, protects those who have no antibodies, and protects children by the time they attend day care. In India the vaccine against hepatitis A is available for the people who can afford it, but the government of India should give this vaccine as a priority in the national immunization schedule.

Seroprevalence and Molecular Characterisation of Human Hepatitis A virus in Serum Samples of Tunisian Patients with Clinical Symptoms of Viral Hepatitis

The aim of the present study was to investigate the seroprevalence of Hepatitis A virus antibodies in patients with clinical symptoms of viral hepatitis and molecular characterization of the detected isolates. The present study deals with the seroprevalence and the genetic diversity of HAV in 400 Tunisian patients presenting in dispensaries (160 patients) and in University Hospitals (240 patients) with hepatitis symptoms between 2006 and 2008. The patients with acute hepatitis were mainly from rural regions. However, the total number of patients was decreased over time. The collected samples were from patients with hepatitis symptoms occurring mainly during January-March (36.7, 26, and 35.5%) and September-December (39.4, 43.4, and 35.5%) during the three years of study, respectively. However, HAV infection was established for only 110 among 400 patients. The detected isolates were clustered within sub-genotype IA. The present study constituted another report of the continued surveillance of HAV infection in the region of Monastir and the molecular characterisation of the detected strains.

A brief review of foodborne zoonoses in China

Foodborne zoonoses have a major impact on public health in China. Its booming economy and rapid socioeconomic changes have affected food production, food supplies and food consumption habits, resulting in an increase in the number of outbreaks of foodborne zoonoses. Both emerging and re-emerging foodborne zoonoses have attracted increasing national and international attention in recent years. This paper briefly reviews the main foodborne zoonoses that have had a major impact on public health over the last 20 years in China. The major causative microorganisms, including foodborne bacteria, parasites and viruses, are discussed. The prevention and control of foodborne zoonoses are difficult challenges in China. The information provided here may aid the development of effective prevention and control strategies for foodborne zoonoses.

Seroprevalence of anti-HAV among patients with chronic viral liver disease

AIM: To investigate the current seroprevalence of hepatitis A virus (HAV) antibodies in patients with chronic viral liver disease in Korea. We also tried to identify the factors affecting the prevalence of HAV antibodies.

METHODS: We performed an analysis of the clinical records of 986 patients (mean age: 49 ± 9 years, 714 males/272 females) with chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection who had undergone HAV antibody testing between January 2008 and December 2009.

RESULTS: The overall prevalence of IgG anti-HAV was 86.61% (854/986) in patients with chronic liver disease and was 88.13% (869/986) in age- and gender-matched patients from the Center for Health Promotion. The anti-HAV prevalence was 80.04% (405/506) in patients with chronic hepatitis B, 86.96% (20/23) in patients with chronic hepatitis C, 93.78% (422/450) in patients with HBV related liver cirrhosis, and 100% (7/7) in patients with HCV related liver cirrhosis. The anti-HAV prevalence according to the decade of age was as follows: 20s (6.67%), 30s (50.86%), 40s (92.29%), 50s (97.77%), and 60s (100%). The anti-HAV prevalence was significantly higher in patients older than 40 years compared with that in patients younger than 40 years of age. Multivariable analysis showed that age ≥ 40 years, female gender and metropolitan cities as the place of residence were independent risk factors for IgG anti-HAV seropositivity.

CONCLUSION: Most Korean patients with chronic liver disease and who are above 40 years of age have already been exposed to hepatitis A virus.

Hepatitis A surveillance and vaccine use in China from 1990 through 2007

Background

Hepatitis A vaccines have been highly effective in preventing hepatitis A. To investigate the epidemiology of hepatitis A in China after hepatitis A vaccine became available, we reviewed reported cases of hepatitis A and the use of hepatitis A vaccine in China during the period from 1990 through 2007.

Methods

Data from the National Notifiable Disease Reporting System from 1990 to 2007 and the Emergency Events Reporting System from 2004 to 2007 were reviewed and epidemiologic characteristics analyzed. Hepatitis A vaccine distribution between 1992 and 2007 was also reviewed.

Results

The incidence of hepatitis A has declined by 90% since 1990, from 56 to 5.9 per 10⁵/year. Declines in age-specific incidence were seen in all age groups, most dramatically among children younger than 10 years. Disease incidence still varies substantially: poorer western provinces have had the highest incidences since 2000. In high-incidence provinces, children younger than 10 years continue to have a high disease incidence. Only 50% of cases were laboratory-confirmed, and only 3% occurred in reported local outbreaks. Over 156 million doses of hepatitis A vaccine have been distributed since 1992, and use has continued to increase since 2003.

Conclusions

Incidence of hepatitis A has decreased in all age groups, likely due to changing socioeconomic conditions and increasing hepatitis A vaccine use. Nevertheless, western populations remain at high risk, with transmission predominantly occurring among children. The epidemiology of hepatitis A transmission is not well understood. Improved surveillance with better laboratory confirmation is needed to monitor the impact of universal hepatitis A vaccination of young children; this strategy began to be implemented in 2008.

Hepatitis A vaccine recommendations

Since licensure in 1995 of a hepatitis A vaccine, the Centers for Disease Control and Prevention and the American Academy of Pediatrics have been implementing an incremental hepatitis A immunization strategy for children. In 1996, children living in populations with the highest rates of disease were targeted for immunization, and in 1999 the program was expanded to immunization of children 2 years and older living in states and counties with rates of hepatitis A that historically have been higher than the national average. The 1999 program has been successful; the current rate of hepatitis A is the lowest ever reported in the United States. Regional, ethnic, and racial differences in the incidence of hepatitis A have been eliminated. The incidence of hepatitis A in adults in immunizing states has decreased significantly, suggesting a strong herd-immunity effect associated with immunization. In 2005, the US Food and Drug Administration changed the youngest approved age of administration of hepatitis A vaccine from 24 to 12 months of age, which facilitated incorporation of the vaccine into the recommended childhood immunization schedule. As the next step in the implementation of the incremental vaccine immunization strategy, the American Academy of Pediatrics now recommends routine administration of a Food and Drug Administration-licensed hepatitis A vaccine to all children 12 to 23 months of age in all states according to a Centers for Disease Control and Prevention-approved immunization schedule. Available data suggest that hepatitis A vaccine can be coadministered with other childhood vaccines without decreasing immunogenicity. Hepatitis A vaccines have proven to be extremely safe. In prelicensure clinical trials of both Havrix (GlaxoSmithKline, Rixensart, Belgium) and Vaqta (Merck & Co Inc, Whitehouse Station, NJ), adverse events were uncommon and mild when they occurred, with resolution typically in less than 1 day. Hepatitis A vaccine is contraindicated in people with a history of severe allergic reaction to a previous dose of hepatitis A vaccine or to a vaccine component. Because the hepatitis A vaccine is an inactivated product, no special precautions are needed for administration to people who are immunocompromised. No data exist about administration of the hepatitis A vaccine to pregnant women, but because it is not a live vaccine, the risk to mother and fetus should be extremely low to nonexistent.

Susceptibility to hepatitis A in patients with chronic liver disease due to hepatitis C virus infection: missed opportunities for vaccination

Hepatitis A virus (HAV) superinfection is associated with a high risk of liver failure and death in patients with underlying chronic liver disease. Although HAV vaccination is recommended for all patients with chronic hepatitis C virus (HCV) infection, little is known about adherence to these recommendations in clinical practice. The aims of this study were to determine the frequency of HAV testing and vaccination among patients with chronic HCV infection. We conducted a retrospective cohort study of 1,193 patients diagnosed with chronic HCV infection over a 1-year period. During 1,646 person-years of follow-up, patients were seen by their primary care provider a median of 10.0 times (interquartile range, 4.0-20.0). HAV antibody testing was performed in 640 subjects (53.6%), and 317 (49.5%) of those tested were susceptible (HAV antibody negative). Only 94 of the 1,193 patients (7.9%) received the HAV vaccine, including 26.8% of the 317 susceptible patients, 0.9% of the 323 patients who were already immune to HAV, and 1.1% of the 553 subjects who were never tested. Among the 94 vaccinated patients, 45 received only one dose of the vaccine. Three of the unvaccinated patients developed acute HAV infection during follow-up, and 1 of them died of acute liver failure. In conclusion, despite published recommendations to vaccinate against HAV in patients with chronic HCV infection, we found that HAV testing and vaccination rates were low in clinical practice. Public health programs to increase awareness about HAV vaccination in patients with chronic liver disease are needed.

Vaccinations for adult solid-organ transplant recipients: current recommendations and protocols

Recipients of solid-organ transplantation are at risk of severe infections due to their life-long immunosuppression. Despite emerging evidence that vaccinations are safe and effective among immunosuppressed patients, most vaccines are still underutilized in these patients. The efficacy, safety, and protocols of several vaccines in this patient population are poorly understood. Timing of vaccination appears to be critical because response to vaccinations is decreased in patients with end-stage organ disease and in the first 6 months after transplantation. For these reasons, the primary immunizations should be given before transplantation, as early as possible during the course of disease. Vaccination strategy should include vaccination of household contacts and health care workers at transplant centers unless contraindicated. No conclusive data are available on the use of immunoadjuvants and screening for protective titers. Most vaccines appear to be safe in solid-organ transplantation recipients, but live vaccines should be avoided until further studies are available. The risk of rejection appears minimal. Recommended vaccines include pneumovax, hepatitis A and B, influenza, and tetanus-diphtheria. We outline specific protocols and recommendations in this particular patient population. Specific contraindications exist for other vaccines, such as yellow fever, oral polio vaccine, bacillus Calmette-Guerin, and vaccinia. We conclude that solid-organ recipients will benefit from consistent immunization practices. Further studies are recommended to improve established protocols in this patient population.

Viral hepatitis in international travellers: risks and prevention

Viral hepatitis is caused by a number of unrelated hepatotrophic viruses, known and unknown. Five hepatitis viruses namely HAV, HBV, HCV, HDV and HEV have been well characterized and the epidemiology and disease pattern of each agent has been defined. In the West, HAV, HBV and HCV are major causes of viral hepatitis. In the East, HEV is the most common cause of viral hepatitis. HAV is ubiquitous in childhood in such countries and accounts for less than 4% of disease in adults. Viral hepatitis becomes a problem to an international traveller when he envisages a journey from low endemic to high endemic area and is susceptible to the infection endemic at his destination. Millions of such potentially susceptible travellers from Europe, the USA, Canada, Japan, Australia, and New Zealand visit endemic areas every year for various reasons. Viral hepatitis is the most common reported immunization-preventable disease among travellers to developing countries. Imported viral hepatitis incapacitates the incumbents for an average of 4-10 weeks. Considering the magnitude of the travel, the number of cases of viral hepatitis and case fatality of around 2%, the disease causes significant morbidity and mortality in such communities. It has been estimated that viral hepatitis occurs 100 times more frequently than typhoid fever and 1,000 times more often than cholera in travellers to developing countries. Hepatitis A is the most common form of viral hepatitis in travellers and cumulative data have shown a risk of 3-6 cases/1,000 persons/month of stay whereas the risk of acquiring hepatitis B is 10 times lower.