Hepatitis A - Another Vaccination Success

Armen Hareyan's picture
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Hepatitis A

Hepatitis is an inflammation of the liver that can have many causes but is commonly due to an infection, usually a virus. There are five types of hepatitis virus, termed A through E. Hepatitis is often referred to as "yellow jaundice" because the skin and eyes turn brownish-yellow from high levels of bilirubin. Bilirubin is a by-product of red blood cell recycling. It leaks from the liver into the blood when the impaired liver can not remove it from the system.

Hepatitis E is not typically seen in the United States unless brought back by a visit to an endemic area such as Mexico, Africa and Asia. Infection with hepatitis E occurs through contaminated food and water, like hepatitis A. Hepatitis D is only a problem when a person has it in conjunction with hepatitis B. Hepatitis C is contracted by contaminated blood such as through intravenous drug use or receipt of blood products and is similar to hepatitis B in that way. Hepatitis B remains a big problem for those who contact blood through drug use, medical procedures, needle punctures with contaminated blood and sexual contact with infected individuals.

Hepatitis A is contracted through ingestion of the virus in contaminated food or water or by contact with an infected person. Although it is possible to contract hepatitis A from contaminated blood by sharing needles, infection typically occurs from eating or drinking contaminated food. Blood donations can be effectively screened so this is no longer a risk.

Hepatitis A is only found in humans. Areas of the world with poor sanitation have a higher incidence. Nonetheless, in the United States, about 11,000 cases were reported in 2001 out of a probable total of about 45,000 occurrences. Epidemiologists estimate only one in four symptomatic cases are reported and half the cases are not symptomatic. Younger people are less likely to have jaundice, making hepatitis less suspect when they present to a physician. Blood tests show about one-third of the U.S. population has had hepatitis A.

Infected people shed hepatitis A virus in their stools and saliva and become infectious about two weeks prior to becoming ill. Consequently, food handlers and close family members may spread infection to others if they do not pay close attention to good hygiene. Fresh produce can become contaminated anywhere from the field if untreated human waste is used for fertilizer to the table if food handlers are infected. Children in and employees of day-care facilities and household contacts of those infected account for about 22 percent of cases while no source is identified in almost half.

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Most of the time, people recover from hepatitis A, but it can take weeks to months with up to a fifth of those infected requiring hospitalization. About 1 percent of cases, usually people older than 50 or with reduced immunity, develop fulminant hepatitis which can have a fatality rate up to 50 percent. The good news is that hepatitis A is preventable.

Previously, a person traveling to an area where hepatitis A was present received a shot of immune serum globulin, formerly called gamma globulin, before traveling to reduce the chance of infection. Immune globulin is concentrated antibodies from donated blood and usually contains sufficient antibody against hepatitis A to prevent it. Its effect wears off after about six months, and it is not completely effective.

In 1995 hepatitis A vaccine was licensed in the United States. Initially it was recommended for vaccination of high risk populations and children older than age 2 in states with the highest incidence of hepatitis A - mostly the states west of the Mississippi. In five years the incidence of hepatitis A plummeted from about 12 cases per 100,000 to less than three. Results have been so impressive that recommendations for vaccination have been expanded. This year the Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention has recommended that all children be immunized for hepatitis A starting at age 1. Children under age 1 may have antibodies to hepatitis A passed from their mothers before birth and the antibodies interfere with the ability to respond to the vaccine.

The vaccine is quite safe with minimal side effects. A second dose six months after the first is recommended for full immunity although there is greater than 97 percent immunity after the first dose. It may be administered with other vaccines but should be given two weeks before possible exposure.

Although it is being added to the routine vaccine regimen for children, anyone may be immunized against hepatitis A. It is highly recommended for people traveling to Africa, Asia, the Caribbean, Mexico, Central and South America, Eastern Europe, the Mediterranean and the Middle East. Others who should receive it are those who are at higher risk due to living in endemic areas, people who work in day-care centers or group homes, food handlers and people who engage in unsafe sexual practices. However, as recent events related to a restaurant outbreak show, hepatitis A can show up anywhere, so it is reasonable for anyone to be immunized.

Insurance companies will likely pay for the vaccine in most cases. If not, cost for the two-dose series is about $175 based on retail cost to physicians. Each case of hepatitis A costs about $2,000 for medical care and results in about a month of lost work or school. Add to that a mortality rate between 0.2 and 2 percent and the vaccine looks like a worthwhile investment.

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