Three to four million people in the United States and an estimated 100,000 in Massachusetts have chronic hepatitis C, compared to 1 million who have HIV.
"(It's) a huge, huge problem worldwide," says Dr. Lucas Wolf, an infectious disease specialist who practices in Gloucester. "It's quickly becoming an extremely important disease in the U.S."
Wolf added that many baby boomers will be diagnosed with cirrhosis (fibrosis or scarring of the liver that prevents it from functioning properly) in the next 10 years, making hepatitis C a public-health threat.
Hepatitis C differs from the other types of hepatitis because nine out of 10 people who get it go on to suffer chronic infection. But unlike hepatitis A and B, there is no preventive vaccine for hepatitis C.
Hepatitis C also differs from the other types because there is virtually no acute phase. Often, it's only detected through routine liver function tests.
"It establishes itself with minimal or no symptoms other than some fatigue and abdominal pain," Wolf said. "People find out through an unexpected route as opposed to being symptomatic. Most of the 4 million infected don't know they have it."
The primary cause of hepatitis C is the sharing of infected needles, Wolf said. Blood-to-blood contact is required, he said, adding that the sharing of needles from heroin use is the most common route of transmission.
But while 80 percent of cases are due to intravenous drug use, there is a smattering of other transmission routes, including infection from nasally inhaled cocaine, tattoos made with dirty needles and blood transfusions before 1992.
Wolf encourages anyone who has ever shared a needle or who was a regular cocaine user to be tested.
"I generally see patients that are boomers and experimented with heroin once or twice in the late 1970s or 1980s," he said.
The North Shore Health Project in Gloucester focuses on hepatitis C and HIV services and offers testing, counseling and holistic health treatments such as acupuncture, massage, Reiki, energy healing, chiropractic care and yoga.
The group also provides case management and advocacy, assists clients with choosing medical care and offers congregate meals, educational programs and a drop-in center to support those facing hepatitis C. All services are free.