Wisconsin reported 1,046 new cases of COVID-19 Thursday, the largest total since Feb. 11, with the daily average nearly doubling over the past month in a surge fueled by more contagious variants and prominent in children, health officials said Thursday.
Half or more of samples recently sequenced from positive cases are of five worrisome variants being closely tracked, and cases overall are growing most among people 18 and younger, said Dr. Ryan Westergaard, a chief medical officer at the state Department of Health Services.
“We are in a new phase of the epidemic that is clearly worse than we were before, and it’s transmission among young people who are driving the change in the curve,” said Westergaard, who noted that schools are reopening and youth sports and other activities are resuming.
Vaccination rates continue to climb, with more than 2 million residents, or 35% of the state’s population, having received at least one dose and 21.9% fully vaccinated. But that’s well below the 80% coverage officials believe is needed to prevent COVID-19 flare-ups, a rate they have said could be achieved by June.
“What we’re doing is racing against the variants with the vaccine,” said Julie Willems Van Dijk, deputy secretary of the state health department.
The officials urged people to wear face masks, maintain distance from others, wash hands frequently, stay home when sick and get vaccinated as soon as possible, now that all state residents 16 and older are eligible for immunization. Those steps can reduce all coronavirus infections, including of the more contagious variants.
“The biggest difference, with the variants now circulating, is that we have to work harder,” Westergaard said. “There’s less room for error.”
Asked if COVID-19 restrictions should be relaxed, as they have been recently statewide and in places like Dane County, he said, “I’m very uncomfortable with the idea of loosening anything.”
The state Supreme Court last week overturned Gov. Tony Evers’ mask mandate. As of Wednesday, residents in Dane County have been allowed to gather in any capacity outdoors without masks, though physical distancing is required.
B117 most common
The B117 variant, first identified in England, is now the most common strain circulating in the United States, the Centers for Disease Control and Prevention said Wednesday. Westergaard said that’s also likely the case in the state.
“I expect that in the next few weeks, if not already, B117 will be the predominant strain in Wisconsin,” he said.
The B117 variant is thought to have accounted for most or all cases in an outbreak announced Monday at an unidentified Dane County child care center involving at least 35 children and adults who tested positive.
The seven-day average of total daily cases in the state is now 733, up from 371 on March 8. Hospitalizations are up somewhat, with 286 patients in hospitals with COVID-19, 47 more than a week ago. The state reported 14 deaths from the coronavirus Thursday, the most since March 20.
Along with the growing proportion of cases being reported among children, Westergaard said the state has had 88 cases of multisystem inflammatory syndrome in children, or MIS-C. In the serious condition, different body parts can become inflamed, including the heart, lungs, kidneys, brain, skin, eyes or gastrointestinal organs.
The average age of the MIS-C cases in Wisconsin is 7, and the rate is 7.5 times higher among Blacks, 4.8 times higher among Hispanics and 2.3 times higher among Asians than whites.
North-central Wisconsin has the state’s highest percentage of COVID-19 samples sequenced that are the B117 variant, while the northeastern part of the state has the highest percentage of the B1427 and B1429 variants first identified in California, according to data made available Thursday.
The proportion of samples sequenced that are the variants being tracked is below the state average in the south-central region, which includes Dane County.
Overall, the state has reported 148 cases of the B117 variant, 15 cases of the B1351 variant first identified in South Africa, four cases of the P1 variant first found in Brazil travelers in Japan, and 216 cases of the B1427 and B1429 variants.
Variants are identified through whole genome sequencing, which previously was done on less than 1% of samples but now is done on about 5% of samples, Westergaard said. Overall, 9,322 samples in the state have been fully sequenced, with the most, 3,994, in south-central Wisconsin, where UW-Madison’s AIDS Vaccine Research Laboratory and the state Laboratory of Hygiene conduct the testing.
In north-central Wisconsin, 5.3% of COVID-19 tests sequenced have been the B117 variant, compared to 1.6% statewide and 1.0% in the south-central region. In northeastern Wisconsin, 5.3% of tests sequenced have been the B1427 or B1429 variants, compared to 2.3% statewide and 1.8% in the south-central region.
Northeastern Wisconsin also has the highest proportion of cases of the B1351 variant, with 0.7%, compared to 0.1% statewide and 0% in the south-central region. Only 171 samples in the north-central region, and 417 in the northeastern region, have been sequenced, which might contribute to the higher percentages of variants found.
Michigan has reported 1,649 cases of the B117 variant, the most of any state except for Florida, according to the CDC. Minnesota is third, with 979 cases.
Studies show the vaccines available against COVID-19 provide protection against variants, but how much is being closely investigated, the state health officials said.