As states lift restrictions and worrisome coronavirus variants spread, scientists and federal health officials have been warning that a fourth surge of cases could arise in the United States even as the nation’s vaccination campaign gathers speed. The seeds of such a surge may now be sprouting in the Upper Midwest and the Northeast.
Michigan is already in tough shape. New cases and hospitalizations there have more than doubled in the last two weeks. The six metro areas in the United States with the greatest number of new cases relative to their population are all in Michigan.
Several other states in the Upper Midwest, including Minnesota and Illinois, have also reported significant increases in new cases and hospitalizations. And in the Northeast, New York and New Jersey have continued to see elevated case counts.
While new cases, hospitalizations and deaths nationwide have declined from their peaks in January, new infections have increased after plateauing.
Further progress in reducing new cases has stalled, hospitalizations have leveled off, and deaths remain near an average of about 800 a day, according to a New York Times database. The average number of new cases has reached nearly 65,000 a day, as of Tuesday, up 19 percent from two weeks ago.
Scientists are particularly concerned about the rising prevalence of variants, which they say could draw out the pandemic. On Wednesday, the director of the Centers for Disease Control and Prevention said a highly infectious variant that was first identified in Britain has now become the most common source of new infections in the United States.
That variant, B.1.1.7, has been found to be most prevalent in Michigan, Florida, Colorado, California, Minnesota and Massachusetts, according to the C.D.C. Until recently, the variant’s rise was somewhat camouflaged by falling rates of infection over all, lulling Americans into a false sense of security and leading to prematurely relaxed restrictions, researchers say.
The C.D.C.’s efforts to track down variants have substantially improved in recent weeks and will continue to grow, in large part because of the $1.75 billion in funds for genomic sequencing in the stimulus package that President Biden signed into law. By contrast, Britain, with a more centralized health care system, began a highly touted sequencing program last year that allowed it to track the spread of the B.1.1.7 variant.
Michigan’s troubles drew attention at a White House news conference on the pandemic on Wednesday. The C.D.C. director, Dr. Rochelle Walensky, said a team from her agency was in the state working to assess outbreaks in correctional facilities, and to boost testing among participants in youth sports. And Andy Slavitt, a senior health policy adviser to President Biden, said the administration had not ruled out sending extra vaccine doses to Michigan.
Mr. Slavitt said he was in direct touch with Gov. Gretchen Whitmer and her aides about what federal assistance might be helpful. “Nothing is off the table in those conversations,” he said.
Other states, including Minnesota, could soon follow Michigan’s path.
“If you look at the trajectory of our curve, it appears we are following Michigan,” said Sara Vetter, interim director of the Minnesota Health Department’s Public Health Laboratory. She added, though, that vaccinations would probably still keep her state from reaching the peak in cases that it saw in November.
Minnesota is averaging 1,826 new cases a day, according to a New York Times database. It surpassed 2,000 new confirmed cases on April 1, a daily figure not seen since early January. Hospitalizations have also climbed about 41 percent from two weeks earlier.
Several factors are driving up case reports in Minnesota, she said. One is people not following public health guidelines. Another is the spread of the B.1.1.7 variant.
State health officials believe that more than half the state’s recent cases are of the B.1.1.7 variant.
Minnesota’s health department has attributed recent outbreaks in schools to the variant, and it has urged schoolchildren and teenagers to get tested at least every two weeks through the end of the school year. An outbreak of B.1.1.7 variant cases connected to participants in youth sports in Carver County prompted a warning from health officials last month.
Dr. Ruth Lynfield, a state epidemiologist, said there had been a notable rise in cases over all in people ages 10 to 19, who accounted for about one in six new cases from mid-February to the end of March, compared with just one in nine over a similar period in October and November.
“It’s a race of vaccine…