DETROIT — Michigan had one of the highest increases in COVID-19 cases per 100,000 people in the country last week, the latest indication of what experts say is a slow surge that could get worse.
Overall, Michigan now ranks 12th nationally for new cases per population over the last seven days, according to data from the federal Centers for Disease Control and Prevention. Two weeks earlier, the state ranked 20th.
From Oct. 11 to Oct. 18, Michigan experienced an increase in cases per 100,000 people of about 2.58%. That's the 10th largest percentage increase in the country, just behind such states as Alaska, Montana and Idaho, which are seeing surges.
The numbers are part of an upward case trend during the past three months, producing a volume of weekly cases that Michigan hasn't experienced since the spring surge began receding. The percentage of COVID-19 tests with positive results and hospitalizations also hit marks not seen since May and are worse than they were a year ago.
Many of the top 10 states for growth of cases per capita have much lower vaccination rates than Michigan, CDC data shows. Alaska, which experienced a 5.42% increase in the number of cases between last week and this week and leads the country in case growth, has about 51.7% of its population fully vaccinated. Michigan is slightly higher at 53%, while the country is about 57% vaccinated.
But vaccination isn't the only factor at play in this most recent surge. Vermont, which is one of the most vaccinated states in the nation with 70.6% of all people fully vaccinated, has the third-highest case increase in the country over the last week, CDC data shows.
That doesn't indicate vaccinations don't work, though. Even adjusted for population, the number of cases per capita are much lower in Vermont than in other states.
"With the delta variant, you don't need many unvaccinated folks to see a surge," said Dr. Vikas Parekh, associate chief medical officer for Michigan Medicine, the University of Michigan's health system. "Even in vaccinated people, there are definitely breakthroughs. That's not a majority of vaccinated people or even a huge percentage, but people who got vaccinated early are seeing waning immunity."
The weather is also likely playing a role. In the South during the hottest parts of the year, COVID cases were way up as people stayed indoors in the air conditioning, said Dr. Matthew Sims, director of infectious disease research for Beaumont Health, Michigan's largest hospital system. As temperatures dropped and people felt more comfortable going outside again, cases also fell in much of the South, he said.
In the upper regions of the nation, the inverse is happening — as it gets cooler, many northerners are finding themselves inside more often.
The return to indoors also coincided with the return to schools, Sims noted. Children are getting hit harder by COVID than they were before, in part, because of schools that don't require students to wear masks, he said.
"When you see symptomatic kids, there's a lot more asymptomatic kids you don't see," Sims said. "But they're both taking it back to their families and spreading it."
Rural counties with low vaccination rates and without mask mandates for students have been driving the recent jumps in Michigan's COVID-19 infections, a Detroit News analysis found last week. Since Sept. 1 — about the time school started in many districts — 15 rural counties have led the state in new cases per population.
In addition, Macomb County is leading the state in the number of schools with new COVID-19 outbreaks, with 25 of the state's 101 new clusters reported there on Monday.
Macomb County has no countywide mask mandate. Eight of the county's 21 districts have some mask rules while 13 others remain mask-optional. The Macomb County Intermediate School District has a mask rule at its buildings.
Eisenhower High School in Shelby Township has the highest number of new cases at a single school — 53 — according to state health officials, while Stevenson High School in Sterling Heights has the second highest with 45 cases. Eisenhower and Stevenson are in the Utica Community Schools district, which has no mask mandate.
All those factors come together to create what Sims called the "slow incline going up" that the state has experienced as cases have continued to rise since the summer.
The state reported 8,496 cases of COVID-19 on Monday, which includes cases from Saturday and Sunday. That brings the statewide pandemic total to 1,090,021 cases reported since March 2020. In Michigan, 21,609 COVID-19 patients have died, including 46 from Saturday to Monday.
Over the last seven days, the state Department of Health and Human Service has reported 25,464 new cases, a 1% increase over the previous seven-day total. However, last week, the percentage of COVID-19 tests with positive results reached 11.5%, the highest rate in 25 weeks. And the number of adults hospitalized with the virus hit 2,072 on Monday, the highest since mid-May. On May 12, the tally was 2,086.
All of the measures are worse than they were a year ago at this time. On Monday, Oct. 19, 2020, the state had 916 adults hospitalized with COVID-19 cases and a positivity rate of about 4.6%. Over the seven-day period of Oct. 13-19, 2020, the state reported 11,341 cases, less than half of the total from the past week.
A data presentation last week by the Michigan Department of Health and Human Services said COVID-19 transmission remained high in the state and "early indicators" showed the delta variant, which causes nearly every COVID-19 case in the U.S., might be surging again.
Experts agree that it is hard to say for sure what comes next. Steve Hall, health officer for the Central Michigan District Health Department, said last week that he believes the state is in a surge that "will last for a while longer."
Parekh said he felt the next few weeks would really be the best indication for how the state will fare over the winter. A bigger surge is possible, he said, or the state could begin to see a drop again.
"It's not very predictable, which makes it challenging to forecast," Parekh said.
Projections from the Institute for Health Metrics and Evaluation, or IHME, at the University of Washington show that based on current trends, Michigan is likely to see a continued rise in the number of cases — and the number of deaths from the virus.
In the worst-case scenarios where Michiganians stop wearing masks and new variants are worse, Michigan could see more than 200 deaths a day during a peak predicted in mid-December, according to the University of Washington forecast. In contrast, if 95% of people started wearing masks, the state could return to levels that more closely reflected summertime rates.
The Michigan Department of Health and Human Services did not answer specific questions on what the state is doing to combat the increase in cases. But department spokeswoman Chelsea Wuth encouraged Michiganians to get vaccinated, calling it "our best defense against the virus."
Doctors and other experts agreed.
"There's no magic formula, but if people get vaccinated and keep taking precautions, like masking, social distancing, limiting the activities you have in environments where that's hard to do, those things will all help," Parekh said. "If you're unvaccinated, you have a totally different level of risk, but those are the things that will help everyone.
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(Staff Writer Jennifer Chambers contributed to this story.)
