What is Hepatitis A?
Hepatitis A is an acute liver disease caused by the hepatitis A virus, a small RNA virus (Picornaviridae) that infects the liver. The disease severity may range from asymptomatic illness to severe disabling symptoms that may last several months. In rare cases, fulminant hepatic failure (acute liver failure) may occur.
What Causes Hepatitis A?
Hepatitis A is caused by ingestion of fecal matter contaminated with the hepatitis A virus. Poor hygiene and inadequate sanitary conditions are associated with the spread of hepatitis A. Consequently, consumption of raw or undercooked shellfish, raw food or vegetables washed with contaminated water or prepared by an infected food handler are risks for hepatitis A acquisition.
What are Hepatitis A Symptoms?
Symptoms are variable and depend on the age of infection, with the severity of illness increasing with the age of infection. In developing countries where hepatitis A is endemic, people are typically infected as children and symptoms are clinically asymptomatic or mild. In the developed world, individuals typically acquire hepatitis A as adults. Symptoms typically manifest 28-30 days (range of 15-50 days) after exposure. Onset of symptoms is usually sudden, with individuals presenting with fever, malaise, loss of appetite, diarrhea, nausea and abdominal discomfort that may be accompanied by jaundice (yellowing of the eyes and skin and passage of dark urine). In some individuals, these symptoms may be severe and accompanied by a slow convalescence. A small portion of individuals (~15%) experience relapsing hepatitis that may last up to a year. Chronic infection with hepatitis A does not occur.
What are Trends in Hepatitis A Epidemiology?
Hepatitis A is prevalent in many parts of the developing world. Specific regions of high or intermediate endemicity include the Indian sub-continent (particularly Bangladesh, India, Nepal and Pakistan), Africa, parts of Asia, South and Central America and the Middle East. While the risk of acquiring hepatitis A in developed countries is low, non-immune travelers are at risk of contracting the disease during visits to countries of high or intermediate endemicity. Hepatitis A is one of the most common travel-related vaccine-preventable diseases.
PaxVax’s Hep A Vaccine Pipeline Candidate
PaxVax is in the process of re-developing a virosomal hepatitis A vaccine that was previously licensed in more than 40 countries.