Oscar Health, which sells coverage in Florida and 14 other states, also ended free Covid treatment this week. It cited the widespread availability of the vaccine as a key reason.

“We started waiving cost sharing for Covid-19 treatment at the peak of the pandemic in 2020, when there were few options available for those who fell ill with the virus,” said Jackie Khan, an Oscar spokeswoman. “We believe that the Covid vaccine is our best way to beat this pandemic, and we are committed to covering it and testing at $0 for our members.”

The new policies generally apply to all patients, including the vaccinated; people who get sick with a breakthrough infection; and children under 12, who are not yet eligible for the vaccine.

“If you have a small kid who gets Covid at school and ends up at the I.C.U., that family is going to now be stuck with the bill even though that patient did not have the ability to get vaccinated,” said Dr. Kao-Ping Chua, a pediatrician at the University of Michigan who researches Covid care costs.