Hepatitis A

Hepatitis is an inflammation of the liver caused by several viruses. There are three principal kinds of hepatitis,  A, B, and C. Hepatitis A is caused by the hepatitis A virus, B by the B virus, and C by the C virus. Hepatitis A occurs worldwide as a sporadic or epidemic illness. It is ubiquitous in developing countries where adults are usually immune due to widespread exposure and mild illness acquired as young children.

Humans are generally susceptible to hepatitis virus infection. Life-long immunity follows natural infection with hepatitis A.

Hepatitis A virus causes an inflammation of the liver manifested by the rapid onset of fever, fatigue, loss of appetite, nausea and abdominal discomfort. Within a few days, jaundice (yellow-coloured skin) appears. In children, the infection may be unapparent or very mild. The illness can be mild and last for 1-2 weeks or can be severely disabling and last several months. Prolonged or relapsing hepatitis may occur for up to 1 year in about 15 percent of the cases. Convalescence may be prolonged, but usually patients make a complete recovery. Chronic infection does not occur. Deaths due to hepatitis A virus infection occur in 0.1 to 0.3 percent of the cases.

There is no specific treatment for acute hepatitis other than supportive measures. 

When administered within 2 weeks of last exposure, hepatitis immune globulin is 80 to 90 percent effective in preventing clinical hepatitis A. In scientific studies, the use of the hepatitis A vaccine within 14 days after exposure provided protection equivalent to that of immune globulin. 

There are high, intermediate and low levels of hepatitis A. Countries with low incomes have high levels; middle income countries have intermediate to low levels; and high income countries have very low levels of Hepatitis A. Most of sub-Saharan Africa, India, and Pakistan have high levels. Intermediate levels can be found in Mexico, Central and South America, northern Africa, and across the Middle East. Low levels are found in eastern European countries, Russia and China. Very low levels are found in Canada, United States, western European countries, and Australia.