(CNN) Many Aetna policyholders will not have to pay for coronavirus treatment if they are hospitalized, the insurer announced Wednesday.

The cost of treatment, which could run hundreds or thousands of dollars, has emerged as a major concern, as Americans fill hospitals nationwide after falling ill with coronavirus. Many insurers, including Aetna, have agreed to waive the cost of testing for many members to encourage people to get checked out if they feel sick.

But Aetna, part of CVS Health and among the nation's largest insurers, is one of the first to cover the cost of treatment for certain members as well, which is a significant step.

Aetna said it will waive cost-sharing and co-pays for inpatient hospital admissions at in-network facilities related to coronavirus for those with employer-based coverage. Larger companies with self-insured plans who pay for the workers' claims can opt-out. The offer, which could apply to as many as 17.7 million of Aetna's roughly 23 million members, is effective through June 1.

Aetna previously agreed to pick up the tab for telemedicine visits