Burden of disease and associated complications of hepatitis a in children and adults in Mexico: A retrospective database study

Seroprevalence and Shifting Endemicities of Hepatitis A Virus Infection in Two Different Geographical Areas in the Philippines

INTRODUCTION

Infection with hepatitis A virus (HAV) is often asymptomatic in young children, but most adolescents and adults will have symptoms ranging from nausea and tiredness to acute liver failure and even death. The risk of severe disease is higher in older adults and people with pre-existing liver disease. Immunization is recommended in regions with low HAV endemicity levels, i.e., where people get infected later in life. In the Philippines, recent epidemiologic data on HAV infection are lacking. The objective of this study was to assess age-specific seroprevalence and evaluate risk factors associated with HAV seropositivity.

METHODS

People from two geographic areas (urban and rural) were recruited/enrolled and stratified by age group. HAV-specific immunoglobulin G (IgG) antibodies were measured with a chemiluminescent microparticle immunoassay. Sociodemographic parameters, hepatitis medical history, disease knowledge, hygiene measures and sanitation were assessed via a purpose-made questionnaire. Age at midpoint of population immunity (AMPI) was estimated using Kaplan-Meier curves. Logistic regression analyses were carried out to determine factors that were statistically significantly associated (p < 0.05) with HAV seropositivity.

RESULTS

Overall, 1242 participants were included in the analysis; 250/602 (41.5%) participants from urban regions and 283/640 (44.2%) participants from rural regions tested positive for HAV IgG antibodies. AMPI was 35 and 37 years for the rural and urban region, respectively. Higher education was associated with lower HAV seropositivity prevalence ratios, while not living in the same region for the last 5 years, regularly consuming street food and lack of handwashing after defecation were associated with a higher likelihood of HAV seropositivity.

CONCLUSION

Results suggest that HAV endemicity is low in the Philippines. Factors associated with HAV seropositivity were traveling, consuming street food and lack of basic hygienic gestures. Immunization might be an option to protect vulnerable populations against severe hepatitis A disease.

Global outbreaks of foodborne hepatitis A: Systematic review and meta-analysis

Hepatitis A Virus (HAV) is a significant threat in terms of food safety. A systematic literature search with the research question "What are the clinical outcomes of foodborne Hepatitis A virus infections?" was conducted. The pooled estimate of the outcomes-mortality, hospitalization, and severity rates, along with a 95% confidence interval (CI), was estimated. After screening, 33 studies were included for the data extraction and meta-analysis. The pooled prevalence of hospitalization among the HAV-positive patients was estimated to be 32% (95% CI 21-44), with high heterogeneity (I2 = 98%, p < 0.01). Australia had the highest hospitalization rate, with 82%, followed by Europe (42%). The hospitalization rate showed a significantly increasing trend (beta = 0.015, p=0.002) over the period. The pooled prevalence of mortality among the HAV-positive patients was estimated to be <1%, with low heterogeneity (I2 = 5%, p = 0.39). A wide range of food products were linked with the HAV outbreaks.

Hepatitis A virus infection

Hepatitis A is a vaccine-preventable infection caused by the hepatitis A virus (HAV). Over 150 million new infections of hepatitis A occur annually. HAV causes an acute inflammatory reaction in the liver that usually resolves spontaneously without chronic sequelae. However, up to 20% of patients experience a prolonged or relapsed course and <1% experience acute liver failure. Host factors, such as immunological status, age, pregnancy and underlying hepatic diseases, can affect the severity of disease. Anti-HAV IgG antibodies produced in response to HAV infection persist for life and protect against re-infection; vaccine-induced antibodies against hepatitis A confer long-term protection. The WHO recommends vaccination for individuals at higher risk of infection and/or severe disease in countries with very low and low hepatitis A virus endemicity, and universal childhood vaccination in intermediate endemicity countries. To date, >25 countries worldwide have implemented such programmes, resulting in a reduction in the incidence of HAV infection. Improving hygiene and sanitation, rapid identification of outbreaks and fast and accurate intervention in outbreak control are essential to reducing HAV transmission.

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.