Hepatitis A Vaccine
Hepatitis A
Hepatitis A is a viral illness of the liver, which is primarily spread by eating and drinking contaminated food and water. This includes eating raw seafood, uncooked fruits and vegetables, or foods that are contaminated by food handlers. Intimate contact with an infected patient can also spread the disease.
The virus is excreted in the stool, thereby spread by persons who do not practice good hygiene; this is another way to pick up the virus. Symptoms usually occur within 2 and 5 weeks of exposure and may include malaise, fever, headache, loss of appetite, nausea, vomiting and abdominal pain. Other signs that are seen are dark colored urine, light colored stools and jaundice. The disease can manifest itself over a wide spectrum ranging from a mild illness lasting 1-2 weeks to a severe disabling disease lasting several months. Mortality for people over 40 contracting the disease is 4%.Hepatitis A is an important risk for travelers to many areas of the developing world. Crowded living conditions and poor sanitation result in Hepatitis A being highly endemic in these regions of the world; it is present in the western world but is less endemic. The risk for travelers increases with the time spent in these regions either with long trips or with frequency of trips.
Each year in the US, about 100,000 cases of acute Hepatitis A are reported. This is responsible for about $200 million in economic losses and about 100 deaths in the US. Studies have shown that there is an average loss of 27 days from work per episode. With the tremendous increase in business/leisure travel, getting the vaccination makes good medical and economic sense. Inactivation of Hepatitis A virus is achieved by boiling or cooking food or water to 85 degrees C for at least 1 minute; proper chlorination of tap water also inactivates the virus. Hepatitis A vaccines have been available in the US since 1995, there are 2 vaccines with a reported efficacy rate of between 94-100%. The recommended schedule for both vaccines is a primary vaccine followed by a second dose 6-12 months after the primary one.
After the second one the projected protective antibody levels last for up to 20 years. Immune globulin, which is prepared from pooled plasma of several donors, also provides protection , but for shorter periods of 3-6 months depending on the dose used. Travelers less than 2 years of age are given the immune globulin because neither vaccine is licensed for this age group.
An easy rule to minimize food related illness is to — “boil it, cook it or forget it!”