In 1972, Vernon Sears was fresh out of the Marine Corps, with time on his hands and a feeling of omnipotence. One day he took up a friend's offer and injected methamphetamine, the drug known as speed.
"If I counted on one hand the number of times I tried it, I'd have fingers left over," he said recently.
It didn't matter, though, that this period of risky experimentation was brief. In a shot with a borrowed needle, Sears became infected with the hepatitis C virus. Now a 50-year-old artist living in Prince George's County, Md., Sears is part of a huge, but largely unknown, epidemic in the U.S.
Over the past 30 years, about 4 million Americans have contracted hepatitis C, an infection of the liver that usually is lifelong and incurable. It is four times more common than the AIDS virus. What will happen to those people--1.8% of the country's population--is one of medicine's biggest questions.
"I think it's going to be the next big public health problem in infectious disease, though we're not going to see it until the next century," said David L. Thomas, a hepatitis researcher at the Johns Hopkins University School of Medicine.
Although the existence of the disease had been suspected for decades, the virus that causes the infection was not isolated until 1989. A laboratory test for hepatitis C, and research, quickly followed. Since then, researchers have begun to develop a better understanding of the magnitude of the hepatitis C problem.
The National Institutes of Health held a "consensus conference" in Bethesda, Md., earlier this summer to discuss the latest research. While much remains unknown, a few things are becoming clear about this "emerging" infection.
Hepatitis C rarely causes immediate illness. Often, it is diagnosed by chance, years, or even decades, after a person contracts it. In about 85% of cases, the infection is permanent and people with it become chronic carriers.
In a minority of cases, hepatitis C causes severe liver scarring--cirrhosis--or, more rarely, liver cancer. Although neither complication surfaces until decades after the infection occurs, about 20% of patients are expected to develop them sometime in their lives, according to current projections. Already, complications from hepatitis C are the leading reason for liver transplants in the United States.
"We may have an epidemic of chronic liver disease in 20 years," said Miriam J. Alter, chief epidemiologist of the hepatitis branch of the federal Centers for Disease Control and Prevention in Atlanta. "The medical system may be overcome with individuals . . . coming to get it treated."
Carriers can transmit the virus indefinitely, although not by casual contact. Sexual transmission occurs, but appears to be relatively uncommon. In blood, however, the virus passes with astonishing ease.
Although the hepatitis C virus was isolated only eight years ago, physicians had long suspected a microbe was behind a mild form of liver disease that began to be noticed in the late 1960s in some people who had received blood transfusions. When those patients were tested, they did not have either hepatitis A or hepatitis B.
Doctors called the new liver disease "non-A, non-B" (NANB) hepatitis because they could not identify the virus until decades later. Once they did, doctors determined that most of the cases were actually hepatitis C.
Experts now believe that hepatitis C started to spread to a much larger segment of the population when, by chance, a few of the people infected with it became intravenous drug users decades ago.
By studying those who originally received NANB hepatitis diagnoses, researchers have gotten a picture of the "natural history" of hepatitis C. Mild symptoms, such as fatigue and vague abdominal pain, do not appear for a decade or more. It takes 20 years, on average, for cirrhosis to develop. Liver cancer rarely occurs until nearly 30 years after infection.
The infection is most common among ages 30 to 49. Unlike the blood transfusion cases, these people were neither sick nor middle-aged when they acquired the virus.
In some populations, however, hepatitis C is astonishingly common. In 1992, a survey of people using the emergency room at Johns Hopkins Hospital found that 18% of patients tested positive for hepatitis C. Between 8% and 10% of black men in their 30s or 40s are infected. And when Canadian researchers recruited 600 IV drug users in Vancouver in the spring for a study of a needle-exchange program, they found 90% already infected with hepatitis C. The number of new cases in this country has fallen steeply since 1989.
The only existing treatment for hepatitis C does not work very well. Patients get three weekly injections of interferon-alpha, an antiviral substance made naturally by the body in minute quantities. Given as a drug, interferon can cause flu-like symptoms and depression. A course of treatment costs about $2,500 for six months, and two courses are often given. It only permanently suppresses liver inflammation in 10% to 20% of patients.
Like many patients with the infection, Sears, the artist, was treated not because he had any symptoms, but because a biopsy of his liver showed chronic inflammation in the organ. The inflammation disappeared after a course of interferon in 1994.
Later, however, the enzyme test again became abnormal. Sears' physicians now are giving him a second course of the drug.