Numerous Democratic-leaning states that run their own insurance markets have already reopened enrollment in recent weeks as the coronavirus threat grew. The Trump administration oversees enrollment for about two-thirds of states.

Insurers said they had expected Trump to announce a special enrollment period last Friday based on conversations they had with officials at the Centers for Medicare and Medicaid Services, which runs HealthCare.gov enrollment. It wasn’t immediately clear why the Trump administration decided against the special enrollment period. CMS deferred comment to the White House.

Trump confirmed last week he was seriously considering a special enrollment period, but he also doubled down on his support of a lawsuit by Republican states that could destroy the entire Affordable Care Act, along with coverage for the 20 million people insured through the law.

People losing their workplace coverage have some insurance options outside of the law's marketplaces. They can extend their employer plan for up to 18 months through COBRA, but that's an especially pricey option. Medicaid is also an option for low-income adults in about two-thirds of states that have adopted Obamacare's expansion of the program.

Short-term health insurance alternatives promoted by Trump, which allow enrollment year-round, is also an option for many who entered the crisis without coverage. Those plans offer skimpier coverage and typically exclude insurance protections for preexisting conditions, and some blue states like California and have banned them or severely restricted them. The quality of the plans vary significantly and, depending on the contract, insurers can change coverage terms on the fly and leave patients with exorbitant medical bills.