Jeremy Fritz stopped working as an assistant manager for a fitness center in Carlsbad, Calif., during the pandemic lockdown in the spring when gyms were first closed.

By the end of April, the company operating the fitness center, Active Wellness, eliminated his health insurance. And in July, he was laid off when it became clear the center where he worked would be closed through 2020. Most of the small company’s gyms are still shuttered.

Losing coverage in the middle of the corona¬≠virus crisis, as millions of other Americans have, was like “going into this thunderstorm without an umbrella,” Fritz recalled. Active Wellness put him in touch with an insurance broker, which helped him and his husband sign up for a plan under the Affordable Care Act.

For people such as Fritz, as well as those who qualify for Medicaid under the law, “there is still a safety net that wasn’t there 10 years ago,” said Sara R. Collins, a vice president at the Commonwealth Fund.

But that net is already fraying, with thousands of small businesses that had always expressed difficulty in providing employee health insurance under Obamacare now in far worse trouble because of the pandemic.

Hopes have also dimmed for another federal aid package before the presidential election.

Not only are businesses shedding workers, with the nation’s unemployed numbering roughly 13.6 million, but employers are also cutting expenses such as health coverage, and projections of rising numbers of uninsured have grown bleak.

Tens of millions of people could lose their job-based insurance by the end of the year, said Stan Dorn, director of the National Center for Coverage Innovation at Families USA, the Washington, D.C., consumer group. “The odds are we are on track to have the largest coverage losses in our history,” he said.

While estimates vary,