Oregon health care workers will have to get vaccinated for COVID-19 or face weekly testing, Gov. Kate Brown’s office said Wednesday, in an apparent step to fight the state’s run-away coronavirus case numbers fueled by the delta variant.

The move comes amid a nationwide push to drive up vaccination rates, both for the general public and among health care workers in particular. Brown’s intervention effectively neutralizes an Oregon law that says employers can’t fire health care workers for not being vaccinated.

Brown’s order, through the Oregon Health Authority, sidesteps the law by mandating weekly testing while allowing for an exemption from the requirement for those who can prove they’ve been immunized.

“This new safety measure is necessary to stop delta from causing severe illness among our first line of defense: our doctors, nurses, medical students, and frontline health care workers,” Brown said in a statement announcing the change. “Severe illness from COVID-19 is now largely preventable, and vaccination is clearly our best defense.”

A state-issued vaccine requirement for health care personnel won’t drive vaccinations up to a level necessary to reach herd immunity in Oregon. But it may help shore up a strained health care system from potential staff shortages due to infections, while potentially signaling to employers in other industries that vaccine mandates are a state-supported option.

Brown’s move comes less than three weeks after The Oregonian/OregonLive highlighted the unique problems Oregon’s health care system and patients face due to an obscure law dating to 1989, which prohibits those systems from requiring vaccinations among employees and firing those who refuse.

Oregon appears to be the only state in the nation with the prohibition specifically for health care workers, and one of the sponsors of the bill was perplexed by the ramifications, saying, “Why the hell did we do that?”

Scrutiny of the law came too late for lawmakers to act this year, said Rep. Lisa Reynolds, D- Portland, who has said she believes it should be changed. For months, vaccines were in such high demand it wasn’t yet clear that tens of thousands of health care workers would decline them.

Brown’s office said she plans to address the law in the February 2022 legislative session.

As of the most recent data available, about 70% of Oregon’s 120,000 employed and licensed health care workers had gotten shots.

Of the state’s roughly 12,000 working physicians, 87% have received COVID-19 vaccine shots. Three in four of Oregon’s approximately 39,000 registered nurses are vaccinated. But those rates go down in other groups, with only 64% of paramedics and 57% of certified nursing assistants vaccinated.

The Oregon Health Authority will issue a regulation codifying Brown’s policy this week. Per the broad-brush strokes described by the governor’s office, health care workers will have to show they’ve been vaccinated for COVID-19 starting Sept. 30 or submit to coronavirus testing once a week. Employers will have to figure out how to pay for the tests, Brown’s office said.

The state chose not to go with a full-blown vaccine mandate because no COVID-19 vaccines have full federal approval, a spokesman for the governor said in an email.

The Oregon Nurses Association, which had previously opposed vaccine mandates, supports Brown’s measure.

“This is a reasonable and sensible approach which respects the individual choices of health care workers while also protecting public health,” union spokesman Scott Palmer said in a statement.

And the Oregon Association of Health Systems and Hospitals, an early and vocal supporter of regulations to override the law, came out on the same side as the nurses association.

“With these additional tools we can better respond to this evolving pandemic and provide the safest possible environment for those who depend on us,” President and Chief Executive Officer Becky Hultberg said in a statement.

The state’s move follows previous announcements by multiple health care systems in Oregon that they will mandate COVID-19 shots for their staff, including Oregon Health & Science University, Kaiser Permanente and PeaceHealth, despite the Oregon law barring mandates.

Brown’s office said the rule will apply to “licensed health care providers, long-term care facilities, outpatient facilities, in-home care, pharmacies, urgent care centers, specialty centers, and more.” There are about 266,000 licensed and unlicensed health care workers in Oregon, according to employment data cited by Brown’s office.

A smorgasbord of efforts to drive up vaccinations have shown moderate success, with only about 5,000 new doses administered per day as of Tuesday. About 91,000 more Oregonians must get shots for 80% of the population to be vaccinated.

While Brown’s lifting of emergency restrictions June 30 was supposed to signal the beginning of the end of the pandemic, circumstances have shifted dramatically since then, with hospitalizations inching closer to 400 Tuesday and case counts rising toward pandemic peak levels.

The de facto vaccination mandate is at least the third policy change to slow the coronavirus since Brown lifted restrictions, with a recent mask mandate in K-12 schools and government buildings and a statewide mask recommendation.

Earlier predictions for this stage of the pandemic assumed more people would be vaccinated and that the virus wouldn’t be nearly as virulent as the delta variant.

The rapid spread of disease has put pressure on employers and local and state officials to do something to curb the spread, whether through mask recommendations or mandates or incentives to get more people vaccinated.

Oregon has turned to a hands-off approach beginning with the June 30 reopening, asking counties to decide if they want to put mask or capacity restrictions in place. But counties have been loath to do so, with none renewing requirements.