Modest declines in COVID-19 numbers in Minnesota, where health authorities reported 307 newly diagnosed cases and 20 deaths on Tuesday, built more evidence that the state is on the downside of at least the first wave of the pandemic.

The Minnesota Department of Health also reported 455 people with the infectious disease in hospital care, including 199 who needed intensive care due to severe respiratory or other symptoms. At peak demand on May 28, there were 606 such patients hospitalized.

The pandemic so far has caused 28,523 known COVID-19 cases and 1,217 deaths in Minnesota — with 968 of those deaths involving mostly older residents of long-term care and assisted-living facilities. The number of COVID-19 cases diagnosed in health care workers has now surpassed 3,000 in Minnesota.

The 20 deaths reported Tuesday included 13 residents of long-term care, and 17 people 70 or older, but also someone 39 or younger. That total was a slight increase from the previous two days, but lower than the seven-day average for the past week.

State Health Commissioner Jan Malcolm on Monday urged Minnesotans to remain cautious, even as the state takes another step toward normalcy on Wednesday with the reopening of limited indoor bar and restaurant service, movie theaters and fitness centers — along with expanded capacity for church services and salons.

“It’s looking kind of like a plateau with some waves within it,” Malcolm said Monday of the declining but erratic pattern of COVID-19 cases in Minnesota.

There is no scientific proof, yet, that summer heat drives down the spread of the novel coronavirus that causes COVID-19, said Kris Ehresmann, state infectious disease director.

“There have been some discussions about whether there might be a seasonality to the virus, having to do with humidity and various things like that,” Ehresmann said on Monday. “At this point, we don’t have good data about how this particular coronavirus will be behaving with respect to seasonality.”

A decline in cases related specifically to climate also could mean an increase when fall or winter arrives, she warned.

The plateau or decline in cases is nonetheless good news for Minnesota health officials, as they assess the impact of increased public mobility following the end on May 18 of a statewide stay-at-home order that lasted 51 days.

Health officials also are concerned about rising cases following protests over the death of George Floyd in police custody, but have some hopes that virus transmission at these demonstrations was lessened by the outdoor air.

Minnesotans are still encouraged to wear masks, work from home when possible, stay at home when sick, and remain 6 feet away from others in public. The new guidelines that take effect Wednesday do allow for indoor gatherings of 10 people, and outdoor gatherings of 25 people.