Hepatitis A vaccine should receive priority in national immunization schedule in India

摘要

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 world-wide 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.