I was diagnosed two and a half years ago with acute hepatitis B virus. My symptoms subsided in a matter of weeks. Periodic screening since has shown normal liver function. Is my liver completely healed? Do I have to avoid liver-taxing substances such as occasional Tylenol and occasional alcohol? Am I contagious to a potential sexual partner? I have received conflicting answers from my gastroenterologist, the health department and my primary physician.

Joanne

I am surprised that there have been conflicting answers to your questions -- the issues are relatively straightforward. Hepatitis B is a common viral infection of the liver. It is responsible for two very important syndromes: acute hepatitis and chronic hepatitis. Acute hepatitis causes symptoms one to three months after exposure. More than half of patients have such a mild illness that it is not recognized as hepatitis at all. Jaundice, or yellowing of the skin and eyes, occurs in about 30 percent. Fever and pain on the right side of the abdomen are the other hallmarks of acute hepatitis. Most patients fully recover, with symptoms resolving in less than three months. In less than 1 percent of cases, there is a rapidly progressive course, causing mental confusion and even death. In about 5 percent of adult cases, the virus is not eradicated and chronic hepatitis results. The course of chronic hepatitis varies from a symptomless carrier state to a severe chronic infection of the liver resulting in cirrhosis (liver scarring) and death.

In virtually all cases, if there is resolution of the acute infection, without progression to fulminant hepatitis or chronic infection, there is nothing more to worry about. The liver may show subtle signs of past infection, but the infection never causes any trouble again. There would be no need to worry about alcohol, Tylenol or transmitting the virus to others.

Now, with a few simple tests, we should be able to determine whether your infection completely resolved, or whether you are now chronically infected. Hepatitis B is generally diagnosed by blood testing. We measure antibodies (proteins the body makes to fight infection) and antigens (proteins from the virus itself) to establish the diagnosis of acute and chronic hepatitis B. In the vast majority of cases, the status of the patient can be determined by measuring both "hepatitis B surface antigen" and "hepatitis B surface antibody." In acute hepatitis, the amount of surface antigen in the blood is high. Then, when the immune system starts to control the virus, the surface antibody replaces it. At some point, after the level of antigen has fallen but before the antibody appears in the blood, there may be a window period where neither is detectable. After that, usually either the antigen or the antibody is present.

If only the antibody is present, then the acute infection is over, and the patient is immune to future infection and should have nothing to worry about. If the antigen is still present more than six months after infection, then the patient has chronic hepatitis. He or she will need evaluation to determine the severity of this infection. There are people in whom both antigen and antibody are present. These patients should be considered to have chronic disease, because the antibodies are not controlling the infection. Occasionally, neither antigen nor antibody is present. This can be due to the gradual loss of the antigen or antibody years after infection, or due to the window period I described above. If it is long after infection, and if there is evidence of chronic liver disease, further testing should be done.

In your case, I would measure both the hepatitis B surface antigen and surface antibody. Most likely, you fully recovered from acute hepatitis B, and your surface antibody will be positive and the antigen will be negative. If this is the case, you really do not have much to worry about.