With the coronavirus cases spiking in parts of the South and West, the governors of New Jersey, New York, and Connecticut on Wednesday all but asked residents of those areas to stay away from their states, where infection and fatality rates have declined after three frightening and economically debilitating months.

“We have taken our people through hell and back. And the last thing we need to do is subject our folks to another round,” said New Jersey Gov. Phil Murphy.

Visitors from Alabama, Arizona, Arkansas, Florida, North Carolina, South Carolina, Texas, and Utah — where increases have fueled the nation’s biggest case surge in two months — will be required to quarantine for 14 days, and violators might be subject to penalties. While not an outright ban, the edict was hardly a welcome mat.

New Jersey Gov. Phil Murphy covers his face with a face mask at the end of the coronavirus briefing in Trenton last week.
JOSE F. MORENO / Staff Photographer
New Jersey Gov. Phil Murphy covers his face with a face mask at the end of the coronavirus briefing in Trenton last week.

Nationally, more than 34,000 new cases of the virus were reported Wednesday, the third-highest daily figure on record and the most since April 24. More than half the states, including Delaware, reported increases.

The virus has been especially dangerous for those with preexisting conditions; the Centers for Disease Control and Prevention reported that close to 90% of those who required hospitalization for COVID-19 had one or more such conditions.

As has Pennsylvania, after months of restrictions and social-distancing edicts, New Jersey and New York have witnessed hard-fought declines in case rates.

In imposing the quarantine, Gov. Andrew Cuomo said violators in New York state would be subject to fines of $2,000 for a first violation, and $5,000 for a second.

In this file photo, a tourist poses for a photo on the Brooklyn Bridge. New York and Connecticut joined New Jersey in imposing quarantine rules for certain visitors.
Mark Lennihan / AP
In this file photo, a tourist poses for a photo on the Brooklyn Bridge. New York and Connecticut joined New Jersey in imposing quarantine rules for certain visitors.

How long the order would remain in effect was as uncertain as the course of the coronavirus itself. In the meantime, on Wednesday organizers canceled this year’s New York City Marathon, the world’s largest, scheduled for November.

Cuomo said that to detect visitors from hot spots, the state might enlist anyone from hotel clerks to police officers to stop out-of-state vehicles.

Murphy did not specify whether New Jersey planned to issue fines similar to New York’s but said Garden State health officials would mount an aggressive public-relations campaign through signs in airports, on highways, and elsewhere.

“Constitutionally, we’re not allowed to put up border checks,” he said. “We’re asking folks to take on a big amount of responsibility.

“We’ve been clobbered by this virus.”

Philadelphia Health Commissioner Thomas Farley said he also was concerned about what a rise in new cases elsewhere could mean for the city, which on Wednesday reported 108 new cases. That figure fairly parallels the daily numbers of last week. That suggested that the numbers might be “plateauing,” rather than dropping, said Public Health Department spokesperson James Garrow.

Dr. Ala Stanford (left) walks with Health Commissioner Thomas Farley before a news conference with Black doctors earlier this month.
ALEJANDRO A. ALVAREZ / Staff Photographer
Dr. Ala Stanford (left) walks with Health Commissioner Thomas Farley before a news conference with Black doctors earlier this month.

“Whether it picks back up and we continue moving toward zero, or continues at this level, or starts to rise again is something we won’t know for a bit,” he said. The city has reported 25,433 cases of COVID-19, with 1,570 deaths attributed to the virus.

“This epidemic is definitely not over,” Farley said. “The risk right now is rising.”

“COVID-19 is a very wild disease,” said Erica Harris, an emergency physician at Einstein Medical Center. “It’s very hard to predict which way it’s going to go.”

While the CDC data on hospitalizations underscore the perils to those with preexisting conditions — about half involved obesity and/or hypertension — “there are people who can have every single risk factor and still do fine,” Harris said.

And protests against police brutality and racism in Philadelphia and elsewhere in the wake of the killing of George Floyd by a Minneapolis police officer have not yielded a harvest of coronavirus cases, according to a study by the National Bureau of Economic Research.

The authors found strong evidence that stay-at-home behavior actually increased, as people tried to avoid the protests. Curfews and business closures also had the effect of keeping more people inside. That effectively counteracted any decrease in social distancing on the streets, they said.

While Dr. Anthony Fauci, the government’s top infectious-disease expert, characterized the national trends as “disturbing,” locally, the near future held some promise of a return to a modified version of pre-coronavirus life.

Philadelphia and its Pennsylvania collar counties will enter the state’s “green” phase of restrictions on Friday in which indoor dining at restaurants can resume but at restricted capacity. Although it has announced that all public pools will be closed, Philadelphia will allow private pools to open.

And great news for those who have been somewhat wary about looking in mirrors these days, hair salons will be able to reopen on Friday.

Barber Tammy Boner cuts the hair of Kevin Maull of Haddon Township at Haddon Township Barber Shop on Haddon Avenue on Monday. Philadelphia hair salons soon will be allowed to open.
TOM GRALISH / Staff Photographer
Barber Tammy Boner cuts the hair of Kevin Maull of Haddon Township at Haddon Township Barber Shop on Haddon Avenue on Monday. Philadelphia hair salons soon will be allowed to open.

Across the river, New Jersey Transit and light rail will return to full weekday service on Monday, Murphy said.

Movie theaters, concert venues, performing-arts centers, nightclubs, and gyms will remain closed, but fitness centers can allow individual training sessions by appointment.

And Murphy said that museums, aquariums, bowling alleys, shooting ranges, arcades, other indoor recreational facilities, and libraries can open at 25% capacity as of July 2. The state will require heightened sanitation measures, social distancing, and face coverings or masks.

Six Flags Great Adventure in Jackson Township, Ocean County, announced on Wednesday it will reopen July 3 to members and season-pass holders, and to the general public on July 4.

As for whether Philadelphia will follow New York’s lead and cancel its marathon, Mayor Jim Kenney’s administration said that no decision had been made. For now, both the marathon, slated for Nov. 22, and the Broad Street Run, moved from early May to Oct. 4, remain on schedule.

Phillies Bryce Harper batting in March in Clearwater, Fla., before spring training was interrupted.
YONG KIM / Staff Photographer
Phillies Bryce Harper batting in March in Clearwater, Fla., before spring training was interrupted.

And come next Wednesday, the Phillies are to resume their “spring” training to prepare for what likely would be a 60-game mini-season, with at least some players working out at Citizens Bank Park. The team also might use facilities at FDR Park and those of its Triple A affiliate in the Lehigh Valley.

Major League Baseball says the real games will start later next month, likely July 23 or 24.

Coronavirus permitting.

Contributing to this article were staff writers Matt Breen, Dominique DeMoe, Laura McCrystal, Justine McDaniel, Ellie Rushing, and Sarah Gantz.