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Covid-19 infections and hospitalizations are rising once again, prompting a new wave of cancellations and disruptions as the country prepares for another pandemic holiday season.

With the US averaging 118,717 new Covid-19 cases each day – 40% higher than a month ago, per Johns Hopkins University data – some colleges and universities are moving to online classes and exams while multiple Broadway shows are canceling performances and professional sports leagues are postponing games.

In New York City, the test positivity rate of PCR tests doubled between December 9 and 12, rising from 3.9% to 7.8%, according to mayoral adviser Dr. Jay Varma, who tweeted Thursday, “We’ve never seen this before in #NYC.”

Nationwide, 1,326 Covid-19 deaths are being reported each day on average, according to Johns Hopkins data, a 12% increase compared to a month prior.

Coronavirus hospitalizations continue to climb, having now trended upward for more than two months as hospitals across the country face staffing shortages. According to the US Department of Health and Human Services, 67,306 are hospitalized with Covid-19, 40% higher than a month ago. Beds in intensive care units are 78% full, and one in five of those patients are Covid-19 patients.

“The cases are going up,” Dr. Anthony Fauci told CNN’s Wolf Blitzer on Wednesday night. “We have an average of about 117,000 cases. We have an increase the percentage of hospitalizations. Deaths are still over a thousand. Then you have, looking over your shoulder, the Omicron variant, which we know, from what’s going on in South Africa and in the UK, is a highly transmissible virus.”

The upticks come as the Omicron variant – which scientists believe to be more contagious, though most cases so far appear to be mild – is identified in a growing number of US states. Health officials in Alabama and Kansas on Thursday announced Omicron cases in their states.

Experts such as Fauci, the director of the National Institute of Allergy and Infectious Diseases, have said it is likely the Omicron variant will become the dominant strain, though the US continues to struggle with the Delta variant. Omicron, however, has shown in other countries that “it has an extraordinary ability to transmit efficiently and spread,” Facui told ABC’s “Good Morning America” on Thursday.

“It has what we call a doubling time of about three days,” he said, adding, “if you do the math on that … very soon it’s going to be the dominant variant.”

“We’ve seen that in South Africa, we’re seeing it in the UK, and I’m absolutely certain that’s what we’re going to be seeing here relatively soon,” he said.

Dr. Jeanne Marrazzo, a professor of infectious diseases at the University of Alabama at Birmingham, agreed. Based on what’s happening in the UK, she said, “we are almost certainly going to be in for what we’re seeing already, which is an early surge, or I should say an early stage of the surge that is probably going to be informed by Omicron.”

Health officials are highlighting the importance for Covid-19 vaccines and boosters. While there’s “no doubt” vaccinated individuals will be infected by Omicron, Fauci told Blitzer, “if you want to be optimally protected and you’re vaccinated, get boosted.”

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Universities move online as Broadway cancels performances

Covid-19 cases have caused a number of colleges and universities to shift to online classes and exams and cancel student gatherings and events: Princeton University, New York University, Cornell University and Middlebury College in Vermont announced in recent days their fall semesters would conclude remotely following a rise in cases on their campuses.

In an email to students Wednesday, NYU Provost Katherine Fleming said a “considerable acceleration in the rate of new cases” was “not a cause for alarm, but it is a cause for concern, caution and appropriate actions.”

Princeton University announced Wednesday all undergraduate exams would shift to a remote format to allow students to “leave campus at their earliest conveniences.” Indoor gatherings where face coverings can’t be worn are also canceled or postponed through January 7, 2022.

Similarly, the Manhattan District Attorney’s Office is facing staff shortages in the wake of a Covid-19 outbreak following an offsite holiday party.

The uptick in cases “has caused significant staffing shortages, disruptions to the department’s practice, and other challenges,” Administrative Assistant District Attorney Bonnie Sard said in a letter to staff.

It’s unclear how many staff members tested positive, and a representative for the office would not elaborate on the outbreak’s impact. Those who have tested positive must quarantine, Sard said, and numerous staff of the impacted department have been asked not to come into the office out of an abundance of caution.

Multiple Broadway shows, including “Hamilton,” have canceled performances this week due to Covid-19. The cancellations come just weeks after shows began to reopen following an extended pandemic hiatus. The announcement by “Hamilton” – which cited “breakthrough Covid-19 cases” – came less than an hour before its 8 p.m. ET performance was scheduled to start Wednesday evening.

Professional sports leagues are also dealing with increases in Covid-19 cases, offering a “window” into wider community spread, according to former US Surgeon General Dr. Jerome Adams.

The NFL acknowledged Wednesday the uptick in cases among its players and teams, including the Cleveland Browns, scheduled to host the Las Vegas Raiders on Saturday. Despite the growing number of players added to the Browns’ reserve list, there are no plans to postpone the game, NFL Commissioner Roger Goodell told reporters.

Separately, the NBA and the NHL announced in recent days the postponement of games due to Covid-19 cases or health and safety protocols. And on Thursday, citing “the spiraling rise of COVID-19 cases in the region,” the Montreal Canadiens announced their home game against the Philadelphia Flyers would be played that evening without fans, at the request of Quebec health officials.

Adams on Thursday told CNN’s “New Day” others should pay attention to pro sports, saying, “They’re really a window into community spread.”

“Kudos to the sports leagues because they are actually doing a fantastic job of surveillance testing,” Adams said. “And the rest of the country, we’re driving a car down a dark road with the headlights off while looking in the rearview mirror, and we hit a bump and we say what was that? That’s our surveillance system right now for Covid.”

Officials continue to push vaccines and boosters

Rising infections and the specter of the Omicron variant have federal health officials once again urging Americans to get vaccinated and, if eligible, get their booster doses.

While it’s reassuring Omicron infections appear to be less severe, “that’s really only true probably if you’re a healthy person who’s been immunized, and ideally immunized with three shots,” Dr. Marrazzo told CNN’s Kate Bolduan on Thursday.

“What we don’t know yet is what the degree of severe illness is going to be with this variant,” she said. “And we still have so many places that don’t even have primary vaccination coverage above 50%, let alone booster coverage.”

Those who are vulnerable to the virus remain those who are not vaccinated, Fauci said, though he hopes that a potential surge driven by Omicron will spur more people to get inoculated. “We have the tools to be able to blunt this. We just need to implement them.”

Many Americans appear to be heeding the advice: About 1.8 million vaccine doses have been administered each day over the past week, according to the US Centers for Disease Control and Prevention. More than half those doses were boosters, and about 413,000 people are initiating vaccinations each day.

However, with boosters now widely available, officials are also debating what should qualify as “fully vaccinated” moving forward. Currently, the federal government considers people to be fully vaccinated if they’ve received two doses of Moderna’s or Pfizer/BioNTech’s vaccines, or a single dose of the Johnson & Johnson vaccine.

“I actually really think it’s important for people to understand, the CDC, the White House – many scientists have said this, most doctors have said this – need to change the definition of fully vaccinated, especially for J&J,” Adams said Thursday.

That hasn’t happened. On Wednesday, CDC Director Dr. Rochelle Walensky said officials are “continuing to follow that science and it is literally evolving daily. And as that science evolves, we will continue to review the data and update our recommendations as necessary.”

Fauci similarly called the definition of “fully vaccinated” a “semantic thing for regulation,” underscoring that what’s important is that people get a booster shot.

Separately, the CDC’s Advisory Committee on Immunization Practices on Thursday voted to recommend the vaccines by Pfizer and Moderna over J&J’s. The committee’s vote came after it heard new data indicating a rare blood clotting syndrome was more common among people who recently got a J&J vaccine than was previously believed.

CNN’s Deidre McPhillips, Maggie Fox, Jacqueline Howard, Paul P. Murphy, Nora Neus, Elizabeth Stuart and Sahar Akbarzai contributed to this report.