Increasing Burden of Hepatitis A in Adolescents and Adults and the Need for Long-Term Protection: A Review from the Indian Subcontinent

Abstract

Hepatitis A, an acute inflammatory liver disease caused by hepatitis A virus (HAV) infection from close contact with infected people, is highly endemic in the Indian subcontinent. Due to poor sanitary conditions, most of the population is exposed to the virus in childhood. At this age, the disease is asymptomatic and provides lifelong protection against the disease. Due to rapid socioeconomic development in some areas, however, pockets of the population are reaching adolescence/ adulthood without prior exposure to the virus and are thus susceptible to infection. At these ages, infection carries a higher risk of symptomatic disease and complications including mortality. This review of epidemiology and burden of disease studies in the Indian subcontinent, published since 2005, shows increasing evidence of a shift from high to intermediate endemicity in high-income-typically urban-populations. The prevalence of anti-HAV antibodies (previously reported at [ 90%) is lower now in adolescents and young adults (e.g., around 80% in Bangladesh and 55% in 5-15 years in India). As a result, HAV is responsible for more acute viral hepatitis predominantly in this age group (e.g., [ 15 years: 3.

Food products as potential carriers of SARS-CoV-2

“…The incubation period generally ranges between 15 and 50 days, during which the viral particles are shed by an infected person. The prevalence of HAV is correlated with sanitation, unavailability of safe drinking water, and socioeconomic condition ( Agrawal et al, 2019 ). Although most outbreaks of HAV take place during the establishment of food products and due to cross-contamination by a food handler, contamination of food before distribution lead to more widespread foodborne outbreaks.…”

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

“…fever, malaise, diarrhea) 51 and providing long-term immunity against HAV. 52 However, if HAV is encountered for the first time in adulthood, most people will have symptoms (e.g. jaundice, pain), and it is associated with a mortality rate of around 1%.…”

“… 53 Historically, many people in India were exposed to HAV during childhood, resulting in life-long protection. 52 However, with improved sanitation and hygiene, children are becoming less likely to be exposed to HAV, resulting in increasing number of adolescents and adults who are at risk of infection, and a paradoxical increase in morbidity and mortality due to HAV. 51 , 52 , 54 , 55 Thus, and taking into account the high heterogeneity across the Indian continent, India is now thought to be shifting from high to intermediate HAV endemicity.…”

“… 52 However, with improved sanitation and hygiene, children are becoming less likely to be exposed to HAV, resulting in increasing number of adolescents and adults who are at risk of infection, and a paradoxical increase in morbidity and mortality due to HAV. 51 , 52 , 54 , 55 Thus, and taking into account the high heterogeneity across the Indian continent, India is now thought to be shifting from high to intermediate HAV endemicity. 51 , 54 This situation is particularly challenging, as in high HAV endemicity areas, most children are exposed, resulting in mild disease and lifelong immunity, while in low endemicity areas, the chance of exposure in adulthood is low.…”

Long-Term Persistence of Antibody Response with Two Doses of Inactivated Hepatitis A Vaccine in Children

“…Awareness in adolescents and adults, however, is low, even though they are at higher risk of more complicated severe disease if not immunised earlier in life. Vaccination in childhood, therefore, provides an opportunity for protection against hepatitis A in adulthood, providing the induced immune response lasts long enough [4]. Several welltolerated, highly immunogenic and effective hepatitis A inactivated vaccines from GSK are available in various doses [360, 720 or 1440 enzyme-linked immunosorbent assay units (EU) of inactivated hepatitis A viral antigen] and schedules (2 or 3 doses), administered as a monovalent hepatitis A vaccine (HAV) or combination hepatitis A and B vaccine (HAB).…”