Hepatitis C is a leading cause of liver cancer and it could impact as many as 5 million Americans.

That’s the bad news. The good news is that if caught early it’s curable nearly 90 percent of the time, Dr. Joseph Lim, director of the Yale Viral Hepatitis Program, said Tuesday.

“A single pill taken for 8 to 12 weeks will likely cure more than 90 percent of the patients,” Lim said. “It’s truly striking and I think it’s in that context where screening actually makes a difference.”

The population at the greatest risk, according to the Centers for Disease Control, are Baby Boomers born between 1945 and 1965. In 2012, the CDC recommended that everyone in that age group — 79 million Americans — get tested for the disease.

Only about one-third of those carrying the virus have been diagnosed, Lim said.

Most of Lim’s patients learn they have the disease after a routine blood test or a life insurance exam.

“It’s relatively uncommon that someone comes in with some type of symptom and then are diagnosed. It’s usually because they are screened for other reasons,” Lim said.

He said there’s also a misconception that it’s only illicit drug users who contract the disease. Intravenous drug use is one way to get the virus, but some patients got it from transfusions before 1992, when blood wasn’t screened for the virus. Others got it from tattoos, and a majority of patients don’t know where they got it.

In an effort to crack down on what Lim and others see as a growing public health epidemic, the General Assembly unanimously passed legislation that requires physicians to screen patients born between 1945 and 1965 for the virus.

According to the CDC, if everyone born during those decades was tested it would prevent more than 120,000 deaths.

Lim understands that not all of his medical colleagues favor the idea of mandated screening for Hepatitis C, but he said it will reduce future medical costs and prevent deaths. He also admits that he is biased because he focuses on viral Hepatitis.

“In a perfect world we wouldn’t need a law, but I think the reality is that because what I know very well first-hand in our own state is that our own physicians are not screening,” Lim said. “There are exceptions to the rule, but that’s the vast minority. The vast majority of physicians are either unaware of these recommendations altogether, or if they are aware, they’re too busy to do it or don’t believe it’s necessary.”

But not everyone agrees with Lim.

The Connecticut State Medical Society and the Connecticut Chapter of the American College of Physicians testified against the bill, which passed on the final day of the legislative session and is on its way to the governor’s desk.

Dr. Robert Nardino, an internist with Northeast Medical Group in New Haven, said the objections to the legislation have nothing to do with screening for Hepatitis C.

“Physicians object to the need to pass laws as a way to entice physicians to do certain procedures or tests,” Nardino said. “Is this the way that we’re going to approach health care now by legislating it?”

The physician groups felt the bill was unnecessary, that it codifies a medical protocol and interferes with the physician-patient relationship.

“We feel resources would be better spent educating physicians and the public of the need for hepatitis screening for citizens born between those years as well as others at high risk, rather than mandated protocols,” the two groups testified in March.

In a phone interview Tuesday, Nardino said that if this helps increase awareness then it might be helpful.

“Educating people about it is more important than them passing a law,” Nardino said. “I think that the legislature should focus on making sure that people who are screened and have Hepatitis C get access to the specialized care they will need.”