A slew of new medications to treat the hepatitis C virus entered the market last year, promising that just about anyone with the disease can be cured. The medications were a groundbreaking development, especially for older patients who’ve suffered through earlier, less effective treatments, only to have the disease return.

“The developments are coming fast and furious like nothing I’ve ever seen before, in terms of treatment improvements,” said Michael Allerton, M.S., who works for The Permanente Medical Group in the fields of HIV and hep C.

Of the over five million people living in the United States thought to be infected with hep C, persons born between 1945 and 1965 have suffered the most acute impact from the disease. The CDC found that of nearly 5,000 hepatitis C patients, three-quarters were born between 1945 and 1965; over three percent of Americans in that generation had been infected. Another study suggested that only half of Americans with hepatitis C had received complete testing for the virus. All this points to a looming rise in hep C diagnoses, now that health authorities have agreed on comprehensive testing for baby boomers.

Two direct-acting antivirals, Sovaldi (sofosbuvir) and Olysio (simpeprevir), have reported cure rates above 90 percent for patients previously thought untreatable—even opening the door to a cure without interferon, a brutal regimen with serious and debilitating side effects that has traditionally been part of hep C treatment.

“They have made treatment available for all. Even those who are interferon ineligible can get treated,” says Diana Sylvestre, M.D., a doctor in Oakland who treats mostly patients with Medi-Cal. “It has been unbelievable.”

Previously, people with existing health problems were often unable to buy coverage and others were excluded from Medicaid. Because the Affordable Care Act has barred these practices, ACA enrollees are reportedly more likely to have hep C. Insurers are scrambling to resolve when and how much they will cover the costs of the new medications.

Gilead has been widely criticized for its $86,000 price tag for a course of treatment with Sovaldi, but some say the outrage is misdirected and mostly generated by insurance companies.

Most Americans with hep C have insurance, says Lorren Sandt, Executive Director of Caring Ambassadors, a national nonprofit that focuses on hepatitis C and lung cancer. And while most people in advanced stages of the disease are older – 65 and up – many with hep C don’t yet have Medicare. Private insurers are resisting paying for treatment for this rise in newly-diagnosed patients.

“A lot of this is, insurance companies for years have been waiting for the [baby boomer] population to age into Medicare so that they didn’t have to take care of them,”

The fear of higher drug costs stems mostly from the jump in number of patients now eligible for treatment, says Sandt.

The previous treatment of interferon was even more expensive, per patient, than newer medications – but its toxicity meant far fewer people could use it. “This is night and day, the difference in therapy,” she says. “Everybody is up in arms, and I hate the price just as much as everyone else. But the reality is, it’s still cheaper therapy and it’s a cure.”

A 2010 study of veterans showed almost 70 percent of veterans weren’t eligible for interferon. Now, says Sandt, with less toxic treatments, the majority of the people living with hepatitis C are candidates for a cure. “All of a sudden, the VA can treat most of their patients,” she says. “So that’s a huge increase [financially] but it’s an increase that’s so much better for patients.”

Still, the aggregate cost poses a problem for fixed budget programs like Medicare and Medicaid. Those programs are working to develop clear, clinical guidelines for which patients qualify to have their treatment paid for.

Sylvestre pointed out that Medi-Cal covers her patients’ drugs on a limited basis. “For patients with more limited fibrosis or who have not tried therapy with a less expensive regimen, the medication request may be denied,” said Sylestre. She said doctors must justify the need for treatment.

“That is disease discrimination,” says Sandt. “We would never, ever tell a breast cancer patient, let’s wait till the cancer gets worse before we treat.”

As it stands, many private insurers are also likely to challenge claims for the high-price regimens.

Project Inform, an HIV and hepatitis C advocacy organization based in San Francisco, compiled a list of California insurance plans’ coverage of available hepatitis C medications. The sheet gives a glimpse into the confusion patients will face when choosing a plan. Plans participating in California’s insurance exchange – Covered California – vary widely in their coverage of hep C medications.

The sheer prevalence of hepatitis C in the United States ensures that the amount spent on prescription drugs will go up – at least temporarily.

Even if the state only paid for treatment for patients with advanced liver fibrosis, said researchers at a March meeting of the California Technology Assessment Forum, first year drug expenditures would increase by $6.3 billion. “Just do the math,” says Allerton. “Figure these pills are about a thousand a piece. Ancillary tests can be $40 thousand a person, multiply that by infected baby boomers, the system can’t handle that.”

The panel concluded that Sovaldi would therefore be a “low value” treatment, considering its cost compared with older drugs, and the supposition that many people with hep C will not develop liver damage. Allerton noted that doctors don’t always know which cases will progress to liver damage. “Then there is the conundrum of, ‘Why wait till people get sick?’”

Hepatitis C is the leading cause of liver transplantation, liver cancer, and cirrhosis. Sandt says that if the costs of treating hep C seem high now, the future costs will be enormous, as the virus continues to spread and make people ill.

“While not everybody gets liver disease, hepatitis C causes other diseases which decrease the quality of life,” she says. “Hep c is an infection – and now we have an outbreak in youth – that we can cure by treating everyone. We can eradicate it from our society.”