As the most severe surge in coronavirus cases yet rages across the country and region, New Jersey on Monday imposed new restrictions on indoor dining and sports, Philadelphia urged people who were in postelection crowds to quarantine, and Pennsylvania Health Secretary Rachel Levine said the new wave’s peak has not been reached.

At the pandemic’s eight-month mark, Pennsylvania is in the midst of a streak of about 3,000 cases a day, and New Jersey more than 2,000 a day.

“We have to get back into the mindset that saw us crush the curve in the spring,” New Jersey Gov. Phil Murphy urged.

New restrictions on New Jersey bars and restaurants and a ban on travel for indoor youth sports teams will go into place Thursday, he announced.

Levine did not indicate Pennsylvania officials were planning to impose restrictions beyond those already in place. But she again said Pennsylvanians should not hold gatherings for Thanksgiving or other holidays with anyone outside their household.

The record-breaking surges continued across the country, particularly in the Midwest and Mountain West — with the rising numbers in this region “a direct reflection of what is occurring across the [country] in almost every state,” Levine said.

On Monday — as the U.S. logged more than 105,000 new cases and the nationwide positivity rate was nearly 8% — Pfizer said early data showed its COVID-19 vaccine appears to be highly effective, and President-elect Joe Biden urged mask-wearing as he previewed plans for his administration that included increased testing, guidance, and supply production.

Making the unveiling of his COVID-19 transition advisory board of doctors and health experts his first address since his Saturday victory speech, Biden acknowledged the alarming wave of infections looks likely to worsen before he takes office Jan. 20, saying the country is “still facing a very dark winter.” He urged Americans to “save tens of thousands” of lives by wearing masks for the next few months.

The surge has ballooned quickly: Pennsylvania saw more than 3,000 new cases in one day for the first time ever on Friday, then reported more than 4,000 new cases in one day on Saturday. The U.S. passed 10 million total cases diagnosed on Sunday, only 10 days after surpassing the nine million case mark.

As of Monday, 7.5% of people being tested in New Jersey were infected, and that rate was nearly 7% in Pennsylvania — both higher than previous weeks and indicative of wide community spread. In Philadelphia, the rate is up to 9.1%.

Cherry Hill Public Schools scrapped plans to resume in-person instruction on Tuesday and pushed the return date to Nov. 30 after three dozen cases broke out among students aged 7 to 18 in multiple schools.

Philadelphia health officials recommended that anyone who participated in the mass postelection celebrations and demonstrations in city streets quarantine for 14 days, and said they should wait seven days after being in the large crowd before getting a coronavirus test.

New Jersey reported 2,075 new cases and 11 deaths on Monday. Hospitalizations are also rising there, Murphy said.

Starting Thursday, restaurants will be barred from indoor service between 10 p.m. and 5 a.m., and bar seating will be prohibited all day. The restrictions will also apply to casinos, which can maintain gaming operations but must stop serving food during those hours. Outdoor and takeout service can continue without interruption.

The rules will also apply to banquet halls; Murphy said weddings or other events planned for the coming weeks should conform to the new guidelines.

However, restaurants will be allowed to move tables closer than six feet apart if they install partitions between them, and will also be permitted to seat individual groups of diners in heated greenhouse-like outdoor “dining bubbles.”

Travel for games and tournaments for indoor youth sports is also prohibited until further notice, Murphy said, citing infections related to youth hockey.

Murphy said the restrictions were “surgical steps” aimed at slowing the spread without resorting to the more severe lockdowns of last spring.

“We know that people are getting sloppy in and around bars as the night goes on,” he said.

Pennsylvania reported 3,402 newly confirmed cases of the virus and four deaths on Monday. It also reported 2,909 new cases and five deaths recorded Sunday. Philadelphia reported 1,772 cases on Monday, representing lab results returned since Friday.

“This is a call to action for everyone in Pennsylvania,” Levine said. “We all need to take steps to prevent the spread of this virus, and if we don’t, we put ourselves, our family, our communities, and our health systems at risk.”

The commonwealth is seeing a steady increase in hospitalizations: About 500 people were admitted to Pennsylvania hospitals due to the virus within the past week, for a total of about 1,734 patients hospitalized as of Monday, Levine said.

Hospitals are not overwhelmed, Levine added, though some in the northern part of the state are strained.

In the Philadelphia region, Delaware County has the highest test positivity rate at 7.6%, followed by Bucks at 6.2%, and Montgomery and Chester, which are both just above 5%, according to state data. Statewide, 52 of the 67 counties have positivity rates above 5%.

Levine said Pfizer’s announcement was encouraging and said Pennsylvania officials “stand ready to distribute and administer” the vaccine when it’s ready. The Pfizer vaccine requires ultracold refrigeration, which Levine said the health department has begun working with health systems to prepare for.

Speculating that broad immunization could begin as soon as April or May, Murphy reminded residents that the restrictions would not be “forever and always.”

“We basically have a six-month window to beat the fatigue back and beat the virus into the ground,” he said.

Staff writers Ellie Silverman, Laura McCrystal, Rob Tornoe, Melanie Burney, and Tom Avril contributed to this article.