Hepatitis B and Hepatitis B Vaccine

Hepatitis B is a serious disease that affects the liver and can result in lifelong infection, cirrhosis (scarring) of the liver, liver cancer, liver failure and even death. The illness comes in acute as well as in chronic form. Either way, a hepatitis B infection can go completely unrecognized. However, the hepatitis B virus is 50 – 100 times more infectious than HIV. The infection is preventable by vaccination.

What is hepatitis B?

Hepatitis B, sometimes called hep B or HPB, is the name of a virus that attacks the liver. It is a hepadnavirus (hepa from hepatotropic – infectious and replicating in the liver – and dna because it is a DNA virus). Once contracted, the virus replicates in the liver and spreads to the blood. Most people who get infected with hepatitis B develop the acute form of the disease. The illness just lasts for just a few weeks and most recover fully. Yet, few people may develop severe liver disease (fulminant hepatic failure) and may even die as a result. Sometimes the virus can cause a longer-term infection, which is called chronic hepatitis B. Over time, chronic hepatitis B can cause serious damage to the liver, such as cirrhosis or liver cancer. Young children and babies who are infected are more likely to contract the chronic form of hepatitis B. It is possible to have hepatitis B and not be aware of it, as its symptoms can be mild or completely absent. However, an infected person can spread the virus to other people through blood and bodily fluids.

Where does hepatitis B come from?

The symptoms of liver diseases like hepatitis B, like jaundice, were described by Hippocrates and found to be infectious as early as the 8th century. In the late 19th century, it was discovered that hepatitis was transmissible through blood transfusions and syringes when epidemics of jaundice broke out during the wars of the 17th to the 19th century. A series of outbreaks after measles and yellow fever vaccinations during World War II provided further evidence that the hepatitis virus was blood-borne. F.O. MacCallum classified viral hepatitis into two types, hepatitis A and hepatitis B; this is essentially when the hepatitis B vaccine history started. In 1965, Baruch Blumberg found the Australia antigen (later known as hepatitis B surface antigen) in the blood of aboriginal people. The antigen was isolated in the late 1970s, which led to the development of the hepatitis B vaccine in 1981.

How is hepatitis B transmitted?

The hepatitis B virus is spread through the blood and other bodily fluids. The disease can be contracted through sharing needles for drug use with an infected person, having sexual sex with an infected person without using a condom, sharing personal items like a toothbrush or a razor or with an infected person, getting a piercing or a tattoo with a tool that was used on an infected person and was not sterilized. A mother with the hepatitis B virus can also pass it on to her baby during the delivery. Medical experts recommend that pregnant women get tested for the hepatitis B virus. If a mother has the virus, her baby may receive shots to help prevent them from becoming infected. Hepatitis B can normally not be contracted from casual contact like hugging, kissing, coughing, sneezing or sharing drinks or food items with an infected person.

What are hepatitis b symptoms?

Most people do not experience any symptoms during the acute infection phase. However, some people (usually adults) do experience symptoms that last several weeks, including a mild fever, persistent headache, abdominal pain, low appetite, extreme fatigue, nausea, diarrhea, constipation, joint pain, muscle aches, a skin rash, dark urine, and jaundice. Symptoms typically appear 3 months after exposure, but may appear any time between 6 weeks and 6 months after exposure. More than 90% of healthy adults who are infected with the hepatitis B virus will recover fully and be completely free of the virus within 6 months. Most persons who have the chronic form of hepatitis B present no symptoms. About 15% – 25% of people with chronic Hepatitis B develop serious liver conditions, like cirrhosis or liver cancer, even though people with these conditions might not present symptoms.

What is the hepatitis b vaccine?

The modern hepatitis B vaccine (HBV) has been available in the United States since 1986. The creation of the vaccine involves the genetic sequence of a protein contained in the virus which is inserted into a yeast cell, and then cultured, purified, and made into a recombinant vaccine. When administered via intramuscular injection, the vaccine safely induces an immune response. It cannot infect the vaccine recipient with the virus. There is a range of hepatitis B vaccines available. It is recommended that the hepatitis vaccine be administered as soon as possible after birth (preferably within 24 hours), which should be followed by 2 or 3 doses to complete the primary series. The complete vaccine series induces protective antibody levels in more than 95% of infants, children and young adults. Protection lasts at least 20 years and is possibly lifelong. The hep B vaccine is very safe and effective. Vaccination has reduced the rate of chronic hepatitis B to less than 1% among immunized children.

What are the hepatitis b vaccine side effects?

The majority of those who receive the hepatitis B vaccine will not experience any adverse reaction at all. The vaccine contains non-infectious material, and cannot

cause hepatitis B infection. Some people will develop pain and tenderness where the shot was given. Others might also experience a low-grade fever. However, serious reactions are very rare. About .001% (less than 1 in 10,000) will experience a serious allergic reaction that can include anaphylaxis (a life-threatening allergic response). More than 100 million people in the United States alone have been vaccinated with the hepatitis B vaccine.

Who should not get the hepatitis B vaccine?

People who have had a severe adverse or serious allergic reaction to a previous dose of the hepatitis B vaccine should not receive any subsequent or additional doses. Persons who are severely or moderately ill should consult with their doctor before receiving any type of vaccine, including the hepatitis B vaccine. That said, the vaccine is considered safe and is recommended by the following professional groups by the Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention, the American Academy of Family Physicians, the American Academy of Pediatrics, and the American Thoracic Society.

Sources:

http://www.cdc.gov/Vaccines/vpd-vac/hepb/default.htm

http://www.cdc.gov/vaccines/hcp/vis/vis-statements/hep-b.pdf

http://www.who.int/mediacentre/factsheets/fs204/en/

http://www.stanford.edu/group/virus/1999/tchang/history.htm

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