As of Sunday, the number of new coronavirus cases has increased by at least 10% or more compared to the week before in 21 states, most of them in the West, according to a CNN analysis of data from Johns Hopkins University.
Cases are rising in Alabama, Alaska, Colorado, Idaho, Maine, Michigan, Minnesota, Montana, Nevada, New Jersey, New Mexico, North Carolina, North Dakota, Oregon, South Carolina, South Dakota, Texas, Utah, Washington state, Wisconsin and Wyoming.
Eighteen states were holding steady. Only 11 -- Arizona, Louisiana, Tennessee, Georgia, Florida, Virginia, Maryland, Connecticut, Rhode Island, Vermont and New Hampshire -- saw decreases of new cases of more than 10% compared to the week prior.
The US could see an explosion of Covid-19 cases in the fall and winter as people exercise less caution and spend more time indoors, where there is a greater likelihood of transmission, according to Dr. Chris Murray, director of the University of Washington's Institute for Health Metrics and Evaluation (IHME).
Murray says the IHME model shows a "huge surge" expected to take off in October "and accelerate in November and December." The IHME model indicates that the country is currently seeing about 765 daily deaths from Covid-19, but that number could jump to 3,000 daily deaths by late December.
New York state on Saturday reported more than 1,000 new cases for the first time since early June, prompting Gov. Andrew Cuomo to warn residents about growing complacent going forward.
"It's vital that New Yorkers continue to practice the basic behaviors that drive our ability to fight Covid-19 as we move into the fall and flu season," Cuomo said in a statement. "Wearing masks, socially distancing and washing hands make a critical difference, as does the deliberate enforcement of state guidance by local governments."
Wisconsin reported 2,817 new cases on Saturday, the state's highest single-day increase in cases. The previous record was set September 18 with 2,533 cases, according to the Wisconsin Department of Health Services. On Sunday, 2,217 new cases were reported for a total of 115,862 cases statewide, according to the department.
Last week, Wisconsin Gov. Tony Evers issued an executive order mandating face coverings in an effort to keep infections down. In a news release, his office attributed rising cases primarily to infections among 18- to 24-year-olds and said the state was "facing a new and dangerous phase" of the pandemic.
"We need your help to stop the spread of this virus, and we all have to do this together," Evers said.
US Centers for Disease Control and Prevention director Dr. Robert Redfield previously warned the fall and winter could be "one of the most difficult times that we experienced in American public health." And with daily cases averaging 40,000 nationwide, the new season could be a challenge, infectious disease expert Dr. Anthony Fauci told Dr. Howard Bauchner, editor-in-chief of the Journal of the American Medical Association on Friday.
"You're going to have to do a lot of things indoors out