While the majority of the country is no longer under advisement to wear masks indoors, the majority of Maine residents should keep wearing masks when they step inside businesses and public spaces, according to new guidance announced by the U.S. Centers for Disease Control and Prevention on Friday.

Thirteen of Maine’s 16 counties are considered to have high potential for health care system strain, the CDC said. Those counties are home to about 84% of the state’s residents based on the latest available census data.

Three counties — Kennebec, Waldo and Somerset — have been reclassified as having medium potential for strain on hospitals. That means masks are now recommended for certain at-risk groups but considered a personal choice for most people, according to the U.S. CDC.

The new guidelines released Feb. 25 take into account hospitalizations and hospital capacity, in addition to virus transmission rates.

“As the virus continues to circulate in our communities, we must focus our metrics beyond just cases in the community and direct our efforts toward protecting people at high risk for severe illness and preventing COVID-19 from overwhelming our hospitals and our health care system,” CDC Director Rochelle Walensky said.

It was not immediately clear why those counties were reclassified and others were not, or why most of Maine remains in the high risk category unlike much of the country.

The CDC said the new guidelines are based on how many people are hospitalized with COVID-19, how much capacity hospitals have for more patients and the current caseloads in each county. The classifications used to be based on two measures — the rate of new COVID-19 cases and the percentage of positive test results over the previous week.

Maine has had an artificially high count of new cases in recent weeks because the Maine CDC was clearing a massive backlog of positive tests that overwhelmed the agency during the peak of the omicron wave in January. It was not immediately clear if the backlogged cases influenced the new classifications.

Maine CDC did not immediately respond to questions about the changes. Maine CDC has generally updated state guidelines in response to federal changes.

Meanwhile, the omicron wave continues to subside in Maine.

The statewide number of hospital inpatients with COVID-19 dropped to 181 on Friday, a 58% decline from the peak of 436 on Jan. 13. Thursday was the first day  in four months that the number of inpatients statewide had dropped below 200.

The number of patients in intensive care dropped to 39 on Friday, the smallest number since mid-August, when the delta variant was taking hold in Maine. Statewide, 14 patients were on ventilators Friday.

With pressures easing on Maine hospitals, the deployment of nearly 200 Maine Army National Guard members came to an end on Friday. The Guard members had been activated in December and January to provide staff support as the omicron surge pushed the limits of hospital capacity.

Gov. Janet Mills issued a statement thanking the Guard and its members for stepping up. “We are immensely grateful for all that you have done and for the sacrifice of your families and your employers,” Mills said.

Meanwhile, the death toll of the pandemic in Maine has continued to rise, partly because of deaths that occurred in past weeks and were later identified as COVID-related through periodic vital records reviews. The total number of Maine lives lost during the pandemic is now 2,042, according to the Maine Center for Disease Control and Prevention.

The state on Friday also added 1,205 confirmed or probable cases of COVID-19, bringing the pandemic total to 225,253.

Those cases do not reflect current conditions because Maine officials have been working to clear the backlog of unprocessed positive COVID-19 tests that reached nearly 60,000 at the peak of the omicron wave.

The state’s shift to a partially automated process for screening tests, together with a dramatic drop in the number of new tests submitted each day, have allowed CDC staff to catch up on several weeks’ worth of cases that had not made it into the state’s official count. State officials have said they hoped to have all the old tests processed by the end of this week.