WASHINGTON — Most American adults need to be checked for hepatitis C, say guidelines released Monday that urge millions more people to get screened for the liver-damaging virus that can fester for decades before it’s spotted.

The call for expanded screening for Americans ages 18 to 79 is the first since 2013 when U.S. health authorities urged all baby boomers to get a one-time hepatitis C test because that age group appeared at particularly high risk.

The U.S. Preventive Services Task Force said Monday that hepatitis C is on the rise because of the opioid crisis, prompting the recommendation to expand testing.

Finding infection early is critical now that drugs are available that cure most people after two to three months of treatment. And the price of those costly medications has dropped sharply.

Authorities estimate only half of people with hepatitis C know they’re infected. The task force concluded that more widespread screening would be cost-saving, giving its recommendation a rating that requires insurance companies to cover testing without patient co-pays.