COVID-19 rates have declined slightly in Minnesota, where no new coronavirus mutations have emerged with the intensity of last fall's delta variant to present a threat to the state.

The seven-day average of lab-confirmed coronavirus infections had remained steady at around 1,400 per day for much of July and August, but dropped below 1,200 per day on Aug. 28, according to the state's weekly pandemic situation report.

The drop in infections appears to have combined with a nursing strike of 15 Twin Cities and Duluth area hospitals this week to reduce hospitalizations as well. The 6,791 patients in Minnesota hospitals on Tuesday, including 385 who had COVID-19, represented the lowest total since May 2021.

Hospitals had planned to delay or reschedule some non-urgent surgeries and appointments to weather the three-day strike at the start of this week, which could explain the 15% decline in total admitted patients in Minnesota from 7,981 on Sept. 9. It's also possible the strike affected the timeliness of hospitals reporting their numbers, though, so the impact of the labor action could become clearer later this fall.

State leaders encouraged Minnesotans to maximize their protection against COVID-19 by seeking the new booster vaccines that add protection against the dominant BA.5 and BA.4 omicron viral variants. They are recommended for anyone 12 and older — two months after their most recent COVID-19 vaccinations or three months after coronavirus infections.

"Staying up to date on your COVID-19 vaccines is a crucial part of protecting our state in the months ahead," said Jan Malcolm, state health commissioner.

Minnesotans also were encouraged earlier this week to order another four free home COVID-19 tests kits. Tests weren't available in many ZIP codes Thursday afternoon but a state official said inventory was being moved around so that people in those areas would have access again.

COVID-19 rates have mostly been flat this summer, but a look back shows some familiar patterns from earlier pandemic waves. Infections rose slightly after the July 4 holiday weekend, when travels and group events allowed for more viral transmission, and peaked in the first week of August. A slight peak of COVID-19 hospitalizations then occurred in mid-August and deaths increased to seven per day in the final week of the month.

The 31 COVID-19 deaths identified so far in September have raised Minnesota's toll in the pandemic to 13,199. Most of the recent COVID-19 deaths have been in seniors.

Death risks from COVID-19 have declined with the availability of antiviral treatments and the amount of immunity in the population from prior infections or recent vaccinations. The Centers for Disease Control and Prevention on Thursday reported that the rate of hospitalized COVID-19 patients who died dropped from 15.1% last fall when delta was predominant to 4.9% this spring when the omicron variant took hold.

Global surveillance had identified a BA.2.75 variant in other countries that could emerge and present the next source of COVID-19 growth. Monitoring by Minnesota wastewater plants has yet to produce any sign of that variant, but new results could change that on Friday.

Viral levels reported by 40 wastewater treatment plants in Minnesota were mostly flat or declining through Sept. 11. Mayo Clinic's 14-day forecast projected continued declines in COVID-19 cases in Minnesota through late September.