Hepatitis B is a serious disease that affects the liver. It is caused by the hepatitis B virus (HBV). HBV infection can vary in severity from a silent infection with no symptoms to a lifelong infection which may result in liver damage, liver cancer and even death. It is estimated that there are 2 billion cases of HBV infection worldwide, with 400 million people chronically infected and 1 million deaths each year from hepatitis B and its complications.

About 30% of those infected with HBV have no signs or symptoms. Some symptoms of acute (short-term) infection are loss of appetite, nausea, vomiting, diarrhea, jaundice (yellow skin and eyes), fatigue and pain in joints and muscles. Acute illness is more common in adults than children. Most people are able to fight off the infection and clear the virus from their blood but this may take up to six months and they can pass on the infection to others while the virus is in their blood. Some people go on to develop a chronic (long-term) infection which can be very serious and often leads to cirrhosis (scarring) of the liver, liver cancer, liver failure or death. Chronic infection is more common in infants and children.

Hepatitis B virus is spread through contact with the blood or body fluids of an infected person. People who are infected can spread the virus even if they have no signs of infection or don’t appear sick. Infection can occur through contact with an infected mother’s blood or body fluids at birth, unprotected sex with an infected partner, sharing needles when injecting drugs, receiving blood transfusions that have not been screened for HBV, or through needlesticks on the job. HBV can also be spread through contact with open cuts or sores, objects that may have blood or body fluids on them such as razors and toothbrushes, or during procedures such as tattooing and body piercing.

The frequency of HBV infection varies markedly throughout the world. Most areas of the United States, Canada, Western Europe, Australia and southern South America have a low (<2%) rate of chronic HBV infection. Areas with a high (>7%) prevalence include most of Africa, the Amazonian areas of South America and parts of South Asia, the Middle East and Eastern Europe. The rest of the world, including Jamaica, has an intermediate prevalence of HBV infection with chronic HBV infection occurring in 2% to 7% of the population.

The best means of preventing HBV infection is the hepatitis B vaccine which is usually given in a series of three shots. Fortunately most healthy adults who are infected with HBV will recover. However this is not true for infants and children -- 90% of infants infected at birth and up to 50% of children infected between 1 and 5 years of age will progress to chronic infection. This is why universal vaccination of infants and children is so important. Vaccination is recommended for all infants beginning at birth or shortly thereafter, as well as children and adolescents through 18 years old who were not previously vaccinated. The vaccine is also recommended for unvaccinated adults who are at increased risk of infection.

The hepatitis B vaccine is safe and effective and offers long-term protection from HBV infection. The vaccine does not contain blood or blood products and cannot cause HBV infection. The most common reactions to the vaccine are pain at the injection site and fever. As with any medicine, a vaccine could cause a serious reaction. However, the risk is extremely small and the hepatitis B vaccine is considered one of the safest vaccines ever made.