Changes in seroprevalence of hepatitis A after the implementation of universal childhood vaccination in Shandong Province, China: A comparison between 2006 and 2014

The Use of Residual Blood Specimens in Seroprevalence Studies for Vaccine-Preventable Diseases: A Scoping Review

Background: Residual blood specimens offer a cost- and time-efficient alternative for conducting serological surveys. However, their use is often criticized due to potential issues with the representativeness of the target population and/or limited availability of associated metadata. We conducted a scoping review to examine where, when, how, and why residual blood specimens have been used in serological surveys for vaccine-preventable diseases (VPDs) and how potential selection biases are addressed. Methods: The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines and identified relevant papers published in 1990-2022. Results: A total of 601 articles met the inclusion criteria after title, abstract screening, and full-text review. The most studied VPDs using residual blood specimens were COVID-19 (27%), hepatitis E (16%), hepatitis B (10%), influenza (9%), HPV (7%), and measles (7%). Residual blood specimens were primarily sourced from diagnostic specimens (61%) or blood and plasma donations (37%). Almost all articles used specimens linked to basic demographic data (e.g., age and sex), with 47% having access to extended demographic data (e.g., geographic location). Common strategies to address potential biases included comparing results with published estimates (78%) and performing stratified analyses (71%). Conclusions: Residual blood specimens are widely used in seroprevalence studies, particularly during emerging disease outbreaks when rapid estimates are critical. However, this review highlighted inconsistencies in how researchers analyze and report the use of residual specimens. We propose a set of recommendations to improve the analysis, reporting, and ethical considerations of serological surveys using residual specimens.

Evolution and Impact of Hepatitis A Epidemiology in Europe-Systematic Literature Review of the Last 20 Years

While globally hepatitis A (hepA) infections occur in 150 million people annually, European high-income countries now have a low endemicity. However, this results in a more susceptible adult population which is prone to severe illness. To determine current epidemiological characteristics, we performed a systematic literature review to assess the severity of hepA disease in the past two decades in 11 European countries (i.e., Denmark, France, Germany, Greece, Hungary, Italy, the Netherlands, Spain, Sweden, Switzerland and the United Kingdom). Literature search was performed using PubMed and Embase between 1 January 2001 and 14 April 2021. Search terms included the disease (hepA), the 11 selected countries, the term 'outbreaks' and its synonyms, outcomes and terms for hepA virus circulation. In total, 43 records reported data on hepA disease outcomes. Hospitalisation rates varied between the countries, with annual rates exceeding 50% at least once in seven countries. The lowest hospitalisation rates were reported for the Netherlands (≤ 32%) and the highest for Greece (≥ 81%). Liver failure, haemorrhagic and other complications were rarely reported, and case fatality rates were low (0.03%-0.26%). Our findings are consistent with the trends observed globally. This systematic literature review highlights the need to increase awareness of hepA risks and to strengthen prevention strategies. Continuous monitoring of epidemiological data is crucial to assess which populations would most benefit from prevention, mainly with respect to future vaccination recommendations.

The Effectiveness of National Expanded Program on Immunization With Hepatitis A Vaccines in the Chinese Mainland: Interrupted Time-Series Analysis

BACKGROUND

The high prevalence of hepatitis A delivered a blow to public health decades ago. The World Health Organization (WHO) set a goal to eliminate viral hepatitis including hepatitis A by 2030. In 2008, hepatitis A vaccines were integrated into the Expanded Program on Immunization (EPI) in China to alleviate the burden of hepatitis A, although the effectiveness of the EPI has not been well investigated.

OBJECTIVE

We aimed to evaluate the intervention effect at both provincial and national levels on the incidence of hepatitis A in the Chinese mainland from 2005 to 2019.

METHODS

Based on the monthly reported number of hepatitis A cases from 2005 to 2019 in each provincial-level administrative division, we adopted generalized additive models with an interrupted time-series design to estimate province-specific effects of the EPI on the incidence of hepatitis A among the target population (children aged 2-9 years) from 2005 to 2019. We then pooled province-specific effect estimates using random-effects meta-analyses. We also assessed the effect among the nontarget population and the whole population.

RESULTS

A total of 98,275 hepatitis A cases among children aged 2-9 years were reported in the Chinese mainland from 2005 to 2019, with an average annual incidence of 5.33 cases per 100,000 persons. Nationally, the EPI decreased the hepatitis A incidence by 80.77% (excess risk [ER] -80.77%, 95% CI -85.86% to -72.92%) during the study period, guarding an annual average of 28.52 (95% empirical CI [eCI] 27.37-29.00) cases per 100,000 persons among the target children against hepatitis A. Western China saw a more significant effect of the EPI on the decrease in the incidence of hepatitis A among the target children. A greater number of target children were protected from onset in Northwest and Southwest China, with an excess incidence rate of -129.72 (95% eCI -135.67 to -117.86) and -66.61 (95% eCI -67.63 to -64.22) cases per 100,000 persons on average, respectively. Intervention effects among nontarget (ER -32.88%, 95% CI -39.76% to -25.21%) and whole populations (ER -31.97%, 95% CI -39.61% to -23.37%) were relatively small.

CONCLUSIONS

The EPI has presented a lasting positive effect on the containment of hepatitis A in the target population in China. The EPI's effect on the target children also provided a degree of indirect protection for unvaccinated individuals. The continuous surveillance of hepatitis A and the maintenance of mass vaccination should shore up the accomplishment in the decline of hepatitis A incidence to ultimately achieve the goal set by the WHO.

The Shifting Epidemiology of Hepatitis A in the World Health Organization Western Pacific Region

Within the past few decades, improvement in sanitation and economic growth has driven a changing epidemiology of hepatitis A in the Western Pacific Region (WPR) of the World Health Organization (WHO). In this review, we gathered available published information on hepatitis A epidemiology of the countries in the WPR and reviewed the trends reported in the literature from the years 2000 to 2021. Many countries have shifted from high endemicity to low endemicity. Moreover, the administration of the hepatitis A vaccine among children in recent years has shifted disease susceptibility to the older population. Seroprevalence among children has decreased in most countries, while nearly 100% seropositivity is seen in mid adulthood. This is contrary to the epidemiology seen in previous decades when most children achieved immunity by age ten. This also presents a paradox in that better living conditions have caused more vulnerability to the older age groups who are at higher risk for severe disease. Given these trends, we recommend vaccination of vulnerable populations such as the older age groups and inclusion of the hepatitis A vaccine in government immunization programs.

Hepatitis a Vaccine as Opportunity of Primary Prevention for Food Handlers: A Narrative Review

The hepatitis A virus (HAV) is still a leading cause of viral hepatitis worldwide. After a long incubation period, the clinical manifestations range from asymptomatic infection to acute liver failure. The severity of the disease increases with age and pre-existing liver disease. The transmission is mainly via person-to-person contact or ingestion of contaminated food or water. Food contamination can occur at any step of the food chain, especially when infected people handle not-heated or otherwise-treated food. HAV is endemic in low-income countries because of poor sanitary and sociodemographic conditions. The populations of developed countries are highly susceptible, and large outbreaks occur when HAV is introduced from endemic countries due to globalization, travel, and movement of foodstuffs. HAV prevention includes hygiene practices, immunoglobulins, and vaccination. Safe and effective inactivated and live attenuated vaccines are available and provide long-term protection. The vaccine targets are children and subjects at increased risk of HAV exposure or serious clinical outcomes. This review discusses the critical role of food handlers in the spread of HAV and the opportunity for food industry employers to consider food handler immunization a tool to manage both food safety in compliance with HACCP principles and food operators' biologic risk.

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.

Clinical and Epidemiological Spectrum of Acute Viral Hepatitis Due to Hepatitis A and E in Children: A Descriptive, Cross-Sectional, Hospital-Based Study

Objective: Acute viral hepatitis (AVH) in children is a serious and major public health concern globally and in developing countries such as Pakistan. We conducted this study to determine the clinical and epidemiological spectrum of AVH due to hepatitis A virus (HAV) and hepatitis E virus (HEV) infection in children.

Methodology: This cross-sectional study was conducted at the Pediatric Medicine Department of a tertiary care hospital from February 20, 2020, to February 20, 2022. A total of 200 children 1-12 years of age who presented with symptoms and signs of AVH were enrolled. Demographic and clinical characteristics were noted, and venous blood was drawn for the assessment of HAV IgM and HEV IgM using an enzyme-linked immunosorbent assay (ELISA). Descriptive statistics are run, and the results are presented as tables.

Results: Of the children, 75% were diagnosed with acute HAV infection. The median duration of illness was six days (range: 2-21 days). The most common age group affected was 6-10 years (43.5%), of which 56.5% were males. Most of the children belonged to low and middle socioeconomic status (86.5%), and 41.5% consumed underground water for drinking. Fever was the most common symptom, followed by appetite loss and yellow discoloration of urine. Alanine aminotransferase (ALT) was significantly high in HEV compared to HAV infection (2060.2±1036.7 versus 1730.7±957.5 IU/L) (P=0.04).

Conclusion: Acute HAV was more prevalent. Those who are male, 6-10 years of age, from lower and middle socioeconomic status, and using underground drinking water were more affected by acute viral hepatitis. The clinical and biochemical presentation of HAV and HEV did not differ significantly.

Viral hepatitis: Milestones, unresolved issues, and future goals

In this review the current overall knowledge on hepatitis A, B, C, D, and E will be discussed. These diseases are all characterized by liver inflammation but have significant differences in distribution, transmission routes, and outcomes. Hepatitis B virus and hepatitis C virus are transmitted by exposure to infected blood, and in addition to acute infection, they can cause chronic hepatitis, which in turn can evolve into cirrhosis. It is estimated that more than 300 million people suffer from chronic hepatitis B or C worldwide. Hepatitis D virus, which is also transmitted by blood, only affects hepatitis B virus infected people, and this dual infection results in worse liver-related outcomes. Hepatitis A and E spread via the fecal-oral route, which corresponds mainly to the ingestion of food or water contaminated with infected stools. However, in developed countries hepatitis E is predominantly a zoonosis. Although hepatitis A virus and hepatitis E virus are usually responsible for a self-limiting hepatitis, a serious, rarely fatal illness is also possible, and in immunosuppressed patients, such as organ transplant recipients, hepatitis E virus infection can become chronic. The description of goals achieved, unresolved issues, and the latest research on this topic may make it possible to speculate on future scenarios in the world of viral hepatitis.

Hepatitis A vaccination and its immunological and epidemiological long-term effects - a review of the evidence

Hepatitis A virus (HAV) infections continue to represent a significant disease burden causing approximately 200 million infections, 30 million symptomatic illnesses and 30,000 deaths each year. Effective and safe hepatitis A vaccines have been available since the early 1990s. Initially developed for individual prophylaxis, HAV vaccines are now increasingly used to control hepatitis A in endemic areas. The human enteral HAV is eradicable in principle, however, HAV eradication is currently not being pursued. Inactivated HAV vaccines are safe and, after two doses, elicit seroprotection in healthy children, adolescents, and young adults for an estimated 30-40 years, if not lifelong, with no need for a later second booster. The long-term effects of the single-dose live-attenuated HAV vaccines are less well documented but available data suggest they are safe and provide long-lasting immunity and protection. A universal mass vaccination strategy (UMV) based on two doses of inactivated vaccine is commonly implemented in endemic countries and eliminates clinical hepatitis A disease in toddlers within a few years. Consequently, older age groups also benefit due to the herd protection effects. Single-dose UMV programs have shown promising outcomes but need to be monitored for many more years in order to document an effective immune memory persistence. In non-endemic countries, prevention efforts need to focus on 'new' risk groups, such as men having sex with men, prisoners, the homeless, and families visiting friends and relatives in endemic countries. This narrative review presents the current evidence regarding the immunological and epidemiological long-term effects of the hepatitis A vaccination and finally discusses emerging issues and areas for research.

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.

Declining trends in Hepatitis A seroprevalence over the past two decades, 1998-2017, in Pune, Western India

Reduction in seroprevalence of Hepatitis A virus (HAV) is known to be associated with improvements in socioeconomic conditions of the community. National Institute of Virology, Pune has been studying seroprevalence of hepatitis viruses in Pune region over the past four decades. In total, 1438 samples were collected from urban general (UGEN), urban lower socioeconomic stratum (ULSES) and rural (RURAL) populations of the Pune district. Based on estimates in previous studies, subjects were enrolled from age groups ‘6–10’, ‘15–25’ and ‘40 + ’ years. HAV seroprevalence in younger population showed a significant decline. A significant decline in HAV seroprevalence in ‘15–25’ years age group in UGEN (from 85.9% to 73.9%; OR = 0.46, 95% CI: 0.25–0.86) and RURAL (from 98.6% to 91.4%; OR = 0.15, 95% CI: 0.05–0.45) populations suggested that the trend probably started more than a decade ago. Seroprevalence of HAV among ULSES ‘6–10’ children was found to be significantly higher (70.4%) than that among the RURAL children (44.2%; OR = 3.0, 95%CI: 1.7–5.2) and UGEN children (40.4%; OR = 3.5, 95%CI: 1.8–6.7). In view of increasing rates of urbanisation in India, ULSES population needs special consideration while designing future studies and viral hepatitis vaccination/elimination strategies. Our findings call for robust population-based studies that consider heterogeneity within populations and dynamics of socio-economic parameters in various regions of a country.