The Food and Drug Administration (FDA) licensed HAVRIX in February 1995 for children (≥2 years), adults and travelers. Hepatitis A vaccine is also available as a combined preparation with Hepatitis B vaccine in the form of TWINRIX (GlaxoSmithKline) Table 1. Other monovalent formalin inactivated HAV vaccines available in market today include AVAXIM (Aventis Pasteur), HEALIVE (Sinovac Biotech Co Ltd), Weisairuian (Institute of Medical Biology of the Chinese Academy of Medical Sciences Kunming), Veraxim (Shanghai Wison Bioengineering Inc) and EPAXAL (Crucell/Berna Biotech). The adverse reactions following vaccination were minimal, and seroconversion after two doses was found to be quite high (99.8%) . Two laboratory-attenuated strains HM175 and CR326F respectively were used for vaccine production. īy 1992, the clinical efficacy of two formalin-inactivated hepatitis A vaccines HAVRIX (Smith-Kline Beecham) and VAQTA (Merck, Sharpe and Dohme) became obvious. Live attenuated hepatitis A vaccine was developed subsequently. In 1991, a preliminary study was published among vaccinees, demonstrating neutralizing antibodies following the administration of formalin-inactivated vaccines. įirst HAV vaccine was developed in early 1900. Joseph Stokes, a pediatrician working at the University of Pennsylvania School of Medicine, used the knowledge in curtailing hepatitis A outbreak among children by administering gamma globulins. Gamma globulin was found to be effective in prevention of measles in susceptible household contacts in the year 1944. According to the WHO, the most effective way to prevent HAV infection is to improve sanitation and immunization. The discovery of hepatitis A virus, its propagation in cell culture and cloning of its genome culminated almost two decades later in the development and licensing of an effective vaccine. Figure 1 depicts the timeline of Hepatitis A virus. The RNA transcripts derived from cDNA clone proved infectious in cell cultures. The viral genome was identified by reverse-transcriptase polymerase chain reaction. The virus was first cultured in the year 1979. While, it was MacCallum who proposed the terms hepatitis A and hepatitis B in the year 1947. The differentiation between infectious hepatitis and serum jaundice was provided by a series of experiments carried out among mentally disabled residents at the Willowbrook State School, Staten Island. Havens et al., at Yale University, United States of America, successfully transmitted jaundice by feeding serum and stool filtrate to 12 volunteers. He published his findings in Munich Medical Weekly in 1942. Voegt successfully transmitted hepatitis A through duodenal juice. Although person-to-person contact was evident, the virus was thought to spread via droplet nuclei. It was not until early 1900s that the mode of transmission of hepatitis A was identified. It was first seen under immune electron microscope in fecal suspension from infected Joliet prison inmates. The virus was identified when the focus of investigation changed from serum to feces. Viral origin of the disease was first indicated by McDonald. The pathologists Bamberger and Virchow proposed the name “catarrhal jaundice”, as they believed the disease to be caused by mucus blockage of common bile duct. Outbreaks resembling hepatitis A have been reported from Europe in the 17th and 18th centuries during the period of war. This has led to a more symptomatic disease, since hepatitis A infection among children is usually asymptomatic this is known as the paradox of Hepatitis A epidemiology. The age of acquiring hepatitis A virus is also shifting toward adolescents and adults. Some countries have experienced shifting of endemicity due to improvement of environmental hygiene, swelled International travel and national recommendations for hepatitis A vaccination. Major geographic differences have existed in endemicity of the disease depending primarily upon hygiene and sanitation practices. Hepatitis A occurs worldwide and frequent outbreaks have been reported over the years. The discovery of hepatitis A virus vaccine is considered a milestone in the history of acute viral hepatitis. The virus is most commonly transmitted through contaminated food, water, or sexual contact (oral-anal sex). It was not until World War II (1973) when hepatitis A virus was first identified by an American virologist, Stephen Mark Feinstone. Hepatitis A virus is a common infectious etiology of acute hepatitis worldwide.
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