LANSING, Mich. (AP) — Michigan will expand its use of a COVID-19 treatment in the hopes of substantially reducing its rising numbers of hospitalizations and deaths, state officials announced Wednesday amid their efforts to bring down the nation’s highest infection rate.

Additional doses of monoclonal antibodies will be given to hospitals and other providers, which will be asked to expand the number of sites where patients can get infusions from the more than 70 that are operating in 37 of Michigan’s 83 counties.

The drugs, delivered intravenously and made by Regeneron Pharmaceuticals and Eli Lily, have concentrated doses of lab-made antibodies to fight COVID-19 and are geared toward people who are at high risk for severe symptoms or having to be hospitalized.

Gov. Gretchen Whitmer said the treatment could save lives, adding that it “very likely” helped then-President Donald Trump when he was infected last fall. People who qualify — an estimated 30% of infected residents — include seniors and those with preexisting or underlying health risks.

“If you are diagnosed with COVID, talk to a physician to see if you are eligible for this treatment,” the governor said. “Time is of the essence with these therapeutics. The sooner you receive them after you test positive, the more effective they will be.”

More than 6,600 residents have been treated with the drugs since they were approved for emergency use in November, with 65% reporting they felt better within two days and less than 5% requiring hospitalization. Whitmer said her administration also was working with the federal government to add doses of remdesivir, an antiviral medicine given to hospitalized patients through an IV.

The state health department on Wednesday reported nearly 8,000 additional COVID-19 cases and 33 deaths from the disease. The number of hospitalized adults with confirmed cases, about 4,000, dipped slightly but remained near the state’s record high. Some hospitals reported being at or near capacity. Case rates and positivity rates have quintupled since mid-February.

The seven-day average of daily confirmed and probable cases was highest for people ages 20 to 39. Hospitalizations were highest among 50- to 69-year-old residents.

“Patients are again lining our hallways like they were last spring. This situation is very serious,” said Dr. Joneigh Khaldun, the state’s chief medical executive and an emergency room doctor in Detroit. “We need to be using every tool in our toolbox right now to get these cases and hospitalizations down.”

She asked every doctor in Michigan to check whether their COVID-19 patients are eligible for the antibody treatment.

Whitmer, a Democrat, continued to push vaccines and masks — not tougher restrictions — as the way out. At least 42% of residents ages 16 and up have received at least one dose. Earlier this week, the director of the Centers for Disease Control and Prevention said Michigan should “close things down” to address the outbreak.

Republicans who have criticized the governor for limits on business capacity and gathering sizes supported her for not tightening them. In a tweet, Senate Majority Leader Mike Shirkey, of Clarklake, applauded Whitmer “for resisting the tremendous pressure to lock our state down and trusting Michiganders to do the right thing.”

In Detroit, Mayor Mike Duggan made a desperate plea to residents to get vaccinated. He said the seven-day positive rate climbed this week to 20.7% compared to 3.5% in mid-March.

“The worst is still ahead of us,” Duggan said.

He displayed a photo of suburban residents in Sterling Heights willing to stand in rain for three hours last week to get a shot. Duggan reminded Detroiters that there was immediate access to drive-up vaccinations at a convention center as well as neighborhood clinics at schools.

About 24% of Detroit residents 16 or older have at least one dose, well below suburban and statewide results. Duggan said his staff is considering whether incentives offered by companies to get people vaccinated would help.

Associated Press writer Ed White in Detroit contributed.