(CNN)As predicted, the US is now grappling with a new Covid-19 surge -- one that could overwhelm hospitals, kill thousands of Americans a day by January and leave even young survivors with long-term complications.
"We went down to the lowest point lately in early September, around 30,000-35,000 new cases a day. Now we're back up to (about) 50,000 new cases a day. And it's going to continue to rise," Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, said Tuesday.
"This is the fall/winter surge that everyone was worried about. And now it's happening. And it's happening especially in the northern Midwest, and the Northern states are getting hit very hard -- Wisconsin, Montana, the Dakotas. But it's going to be nationally soon enough."
Across the country, more than 30 states have reported more Covid-19 cases this past week than they reported the previous week, according to data from Johns Hopkins University.
And Dr. Anthony Fauci, the nation's top infectious disease expert, sounded an alarm about certain states' test-positivity rates, saying they may be a good indicator that steeper climbs in case rates are ahead.
For the whole country, test positivity averaged 5.1% over the past week as of Tuesday. But in at least 13 states, the figure was above 10%: in Alabama, Florida, Iowa, Idaho, Indiana, Kansas, Montana, Nebraska, Nevada, South Dakota, Utah, Wisconsin and Wyoming, according to the COVID Tracking Project.
"You'd like to see (the rates) less than 3%, optimally 1% or less," Fauci, director of the National Institute of Allergy and Infectious Diseases, said at an event hosted by the College of American Pathologists.
"We're starting to see a number of states well above that, which is often -- in fact, invariably -- highly predictive of a resurgence of cases, which historically we know leads to an increase in hospitalizations and then ultimately an increase in deaths," he said.
In Denver, recent case counts are as "high right now as they were at the height of the pandemic back in May," Mayor Michael Hancock said Monday.
He said hospitalizations have also soared, and residents could face tighter Covid-19 restrictions if the numbers keep going up.
Kansas has broken its record for the highest average number of daily cases with more than 700 cases per day this past week, Gov. Laura Kelly said.
More than 1,000 new cases were reported Tuesday in Colorado. "It's very worrisome. It's very alarming. This is our highest single-day caseload since March," Gov. Jared Polis said.
In Wisconsin, a field hospital is opening this week to handle a rapid rise in coronavirus patients. The state recently reported record-high numbers of Covid-19 cases, hospitalizations and daily deaths.
If Americans don't turn the tide, the US could be in for a devastating winter. The University of Washington's Institute for Health Metrics and Evaluation projects more than 135,000 people in the US could die within the next three months.
"This winter -- this November, December, January, February -- could be the worst time in our epidemic," Hotez said. "Get ready to hunker down."
How overwhelmed hospitals can affect all patients
As we've seen throughout this pandemic, surges in new Covid-19 cases may lead to increased hospitalizations and deaths in the following weeks.
At least 10 states have reported record-high Covid-19 hospitalizations since Friday, according to data from the COVID Tracking Project. Five of them -- Arkansas, Montana, North Dakota, Oklahoma and Wisconsin -- reported records on Monday.
"Hospitals could again become overwhelmed," emergency medicine physician Dr. Leana Wen said. "And then we're not just talking about patients with coronavirus who might be in trouble. It's also about other patients who might be coming in for heart attacks and strokes and car accidents who may find a situation that's really untenable."
Kentucky Gov. Andy Beshear expressed concern about a rising number of hospitalizations. The commonwealth reported 741 Kentuckians are currently hospitalized for coronavirus, with 170 in the intensive care unit and 90 on a ventilator, he said.
Utah Gov. Gary Herbert said the state has seen infection rates and case counts skyrocket over the past month to the highest they've been, with new cases hovering around 1,000 per day since October 4.
"We are utilizing 15.8% of our ICU beds to treat COVID-19 patients, more than double what we were before, and our total ICU utilization is at 69.6%," Herbert tweeted. "This leaves our hospitals precariously close to being unable to treat COVID and non-COVID patients in need of critical care."
Some health care workers in the US still don't have adequate personal protective equipment and testing supplies, emergency medicine physician Dr. Megan Ranney said.
"We're quite fearful for what we are heading into," she said.
Nationwide, hospitalizations have been ticking up -- 35,072 were reported Monday, and the daily count has climbed relatively steadily since a recent low of about 28,600 on September 20.
13% increase in child Covid-19 cases in 2 weeks
More children are also being diagnosed with Covid-19, according to the American Academy of Pediatrics and the Children's Hospital Association.
Their latest report found a 13% increase in child cases reported from September 24 to October 8 -- with more than 77,000 new reported infections.
The report looked at data from health departments in 49 states, New York City, the District of Columbia, Puerto Rico and Guam. Children represented about 10.7% of Covid-19 cases in the states that reported cases by age, the report said.
The news comes as many schools have returned to in-person instruction and are navigating challenges that come with new infections.
There's no "one-size-fits-all" strategy to safely returning to classrooms, Fauci said.
The decisions should be based on how widespread infections are in the community and how much surveillance is required, Fauci said.
"When schools are prepared, when they have a plan, when everyone is universally wearing masks, when they're testing people in a surveillance way to get people who are infected out of the system, (and) they know what to do when they're confronted with a person a child or older students who gets infected -- it can work," he said.
A vaccine trial is paused, but that's 'completely expected'
As Americans wait for a safe and effective vaccine, Johnson & Johnson has paused the advanced clinical trial of its experimental vaccine because of an unexplained illness in one of the volunteers, the company announced.
The drugmaker said Tuesday that it didn't know immediately know whether the ill volunteer had received the vaccine candidate or a placebo, and that it had little information about the illness itself.
Johnson & Johnson said that it learned of the illness Sunday and immediately informed the study's independent Data Safety Monitoring Board (DSMB), which is reviewing the illness.
"It's not at all unusual for unexpected illnesses to occur in large studies over their duration," and sometimes they have nothing to do with the drug candidate, Mathai Mammen, global head of research at Johnson & Johnson's pharmaceutical division, Janssen, said Tuesday in the company's third-quarter earnings call.
As of Tuesday morning, the study was still blinded, meaning neither those directly administering the drugs or placebos nor the volunteers know which volunteers are receiving which elements of the study, Mammen said. The DSMB can "unblind" the study to investigate the illness if necessary, he said.
This kind of pause isn't immediately concerning, said Dr. Ashish Jha, dean of the Brown University School of Public Health.
"This is completely expected, and it's just a reminder how ridiculous it is to try and meet a political timeline of having a vaccine before November 3," Jha said, referring to President Donald Trump's wishes to have a vaccine ready for the public by Election Day.
"The Johnson & Johnson trial is the biggest trial of the vaccine that I know of -- 60,000 people," Jha said. "Within that trial, you'd expect a few pauses."
This is the second Phase 3 Covid-19 vaccine trial to hit the pause button in the US. AstraZeneca's vaccine trial was paused last month because of a neurological complication in a volunteer. While that trial has resumed in other parts of the world, it remains paused in the US while health officials investigate.
Fauci said Tuesday that current efforts toward vaccine development are "on a really good track" despite the Johnson & Johnson news.
"A couple of the vaccines are very close to getting some sort of information," Fauci said during a call with the nation's governors, according to audio of the call obtained by CNN.
Fauci mentioned vaccines being tested by Moderna and Pfizer. "We're getting to the point where we're almost being able to look at the first look at the data, which is a predetermined thing done by the data and safety monitoring board," he said.
The vaccine effort, more broadly, "is on really a good track," he said. "We should know by November or December whether or not we have a safe and effective vaccine. ... It is conceivable that we might even know before then."
When a vaccine does become available, health experts have said it's crucial that enough people become immunized for the preventative to be effective -- and many are worried that won't be the case.
"I'm extremely worried about how politicized this situation is around the vaccine and how people are reacting to it," Moncef Slaoui, the scientific head of the US government's initiative to develop a vaccine as soon as possible, said Tuesday.
"We will be fully transparent: People will understand exactly the performance of the vaccines, their safety and their benefit," Slaoui said in an interview on Fox News.
"And I hope people will realize that the only way really to allow us to move away and control this pandemic will be through mass vaccination," he said.