Hepatitis A and Hepatitis A Vaccine

This is a disease of the liver caused by the hepatitis A virus. It affects tens of millions of people each year, though many infected people have little or no symptoms at all. It is especially common in regions with poor sanitation and contaminated drinking water. While most people with hepatitis A symptoms recover without treatment, the best action is prevention with a hepatitis A vaccine.

What is hepatitis A?

Hepatitis A, sometimes called hep A or HAV, is the mild form of acute infectious liver disease that normally has no lasting consequences and subsides without a specific treatment. While most infected people experience no or mild symptoms, some become severely ill for several months. The hepatitis A virus (HAV) is a RNA virus of the picornavirus family that infects and replicates in liver cells. Hepatitis A is typically contracted from contaminated food or water or from close contact with someone who is already infected. Good sanitation and hygiene are important in order to protect against the disease. However, prevention through the hepatitis A vaccine continues to be the best way to cut down the number of hepatitis A infections.

Where does hepatitis A come from?

The earliest descriptions of symptoms of liver diseases like hepatitis A, such as jaundice, were described by Hippocrates. The infectious nature of the disease was discovered in the 8th century. Epidemics of jaundice during the wars in the 17th, 18th and 19th century were traced back to the transmission of the hepatitis virus through blood via blood transfusions and syringes. Further evidence for the blood-borne origin the virus was found after a number of jaundice outbreaks following measles and yellow vaccinations during World War II. It was not until 1947 that Hepatitis A was differentiated from Hepatitis B. Yet, the specific virus was not isolated until the early 1970s. The hepatitis A vaccine was introduced in 1995 and was initially made available to children living in high-risk areas of exposure.

How is hepatitis A transmitted?

The hepatitis virus is mainly transmitted via the fecal-oral route. It can be spread to another person from an infected person who has not adequately washed their hands after using the restroom. Fecal particles containing the virus can be passed to a person through direct touch. Sexual contact with an infected person can also lead to contact with fecal matter. A person may also become infected indirectly through items touched by an infected person. Eating or drinking contaminated food or water may also result in hepatitis A infection. Raw, frozen and undercooked food items, as well as shellfish, fruits and vegetables are the most likely foods to be contaminated. Hepatitis A is not known to be spread via saliva. In very rare cases it has been spread via contaminated blood transfusions.

What are hepatitis A symptoms?

Not everyone that comes into contact with hepatitis A develops symptoms, although they will still be contagious. The virus takes a long time to mature and show symptoms, from two to six weeks. Once they appear, they will increase in intensity over a few days and can last from two to six months. When hepatitis A symptoms do appear, they can show up in a number of ways including a mild fever, a feeling of fatigue, loss of appetite, pain in the abdomen, dark colored urine, pain in the joints, and a yellow color in the eyes or skin. Treatment of hepatitis A is by ameliorating the symptoms until the illness has left the body. There is no direct treatment of the virus once it has infected the liver.

What is the hepatitis A vaccine?

The hepatitis A vaccine history started with its development in 1995, which resulted in a decline in this virus’ occurrence after a peak number of cases in 1995. Two types of hepatitis A vaccines are available: the inactivated and the live, attenuated vaccine. Both vaccines prevent future infection but will not treat a current illness. The hep A vaccine is also available in combination with the hepatitis B vaccine.The vaccine is given as an intramuscular injection in the muscle of the upper arm. The hepatitis A injection is recommended at age 1. A booster injection 6 – 12 months later can provide protection for up to 20 years. Routine vaccinations are also recommended for men who have sexual intercourse with men, people who use street drugs, and people with chronic liver disease, among others. For people who have not had hepatitis A and have not been vaccinated, but who travel to developing countries should consider a pre-departure hepatitis A vaccination. It is important to allow at least two weeks before departure for vaccination. The vaccine contains no live virus and is safe even for people with reduced immune function.

What are the hepatitis A vaccine side effects?

The side effects, if any, from a hepatitis A vaccine are mild and can mimic a slight allergic reaction. Very rarely will the side effects be severe and require medical attention. The most likely side effects from this vaccination last only one to two days and include tenderness in the area of the injection for one to two days, a mild headache lasting two to three days, a feeling of fatigue lasting two to three days and loss of appetite for one to two days.

Who should not get the hepatitis A vaccine?

Someone who has had a severe allergic reaction to other vaccines should not get this vaccine. A severe latex allergy may prevent someone from getting the vaccine because of components in the vaccine itself. Someone currently ill or recovering from a sickness should wait until they are fully recovered before getting the vaccine. A mild illness may not prevent someone from getting the vaccine. Pregnant women should speak with their doctor before getting the vaccine in case they have any concerns about the risk of side effects.

Sources:

http://www.cdc.gov/vaccines/hcp/vis/vis-statements/hep-a.html

http://www.historyofvaccines.org/content/articles/hepatitis-and-hepatitis-b

http://www.immunizationinfo.org/vaccines/hepatitis

Join the conversation