The National Academies

The National Academies: What You Need To Know About Infectious Disease

What You Need To Know About Infectious Disease

Hepatitis B

Hepatitis B is a contagious, usually acute infection of the liver caused by the Hepatitis B virus. The virus can be spread through contact with the blood or other body fluids of an infected person. The most common means of transmission are through sexual contact, childbirth, and contact with the blood of an infected person via cuts or sores on the skin, or by sharing needles when injecting drugs.

An acute episode of Hepatitis B can cause loss of appetite; fatigue; pain in the muscles, joints, or stomach; diarrhea and vomiting; and jaundice. In some cases, people may go on to develop a chronic illness, which can result in liver damage (cirrhosis) and liver cancer. Newborns and children are more likely to develop chronic Hepatitis B than are adults.

For an acute episode, resting, drinking plenty of fluids, and eating a healthy diet are the best ways to let the liver heal. The acute illness usually goes away after 2 to 3 weeks, and the liver returns to normal within 4 to 6 months. During the acute phase, the liver should be monitored with blood tests. Chronic Hepatitis B can be treated with antiviral medications or a medication called peginterferon. People with this condition should avoid alcohol and check with their doctors before taking any medications, including acetaminophen or ibuprofen. Frequent monitoring of liver function is also recommended.

There is a vaccine available for Hepatitis B, and since 1991 children in the United States have routinely received the inoculation. The vaccine is given in a series of three or four shots. Children receive their first shot as a newborn and are done with the regimen by 6 to 18 months of age. All adolescents and adults who were not vaccinated as children should receive the shots. Since widespread vaccination began, the incidence of Hepatitis B has decreased by more than 95 percent among children and by 75 percent in all other age groups.


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What do you know about infectious disease?

Which are larger?

  • Correct!

    Bacteria are 10 to 100 times larger than viruses.

  • Sorry, that’s incorrect.

    Bacteria are 10 to 100 times larger than viruses.

Infectious Disease Defined


A branch of science that deals with the relation of organisms to one another and their physical environment.

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