U.S. businesses and municipalities weigh vaccine mandates as N.Y.C.’s mayor calls for companies to require shots.

U.S.|U.S. businesses and municipalities weigh vaccine mandates as N.Y.C.’s mayor calls for companies to require shots.

• July 23, 2021, 12:47 p.m. ET

As the Delta variant of the coronavirus fuels outbreaks among the unvaccinated across the United States, local governments and private organizations are grappling with whether to put vaccination mandates in place.

To that point, Mayor Bill de Blasio of New York City said on Friday the city might broaden the number of city workers required to get vaccinated or tested weekly, and would consider similar requirements for people to participate in some indoor activities, including dining in restaurants.

He also encouraged private employers to require workers to get vaccinated. City officials have tried to get residents to get the shot on their own, he said in a radio interview on WNYC, but voluntary efforts alone are no longer working.

“I’m calling upon all New York City employers, including our private hospitals, to move immediately to some form of mandate,” said the mayor, who earlier this week announced that the city’s public hospital system would require employees to get vaccinated or get tested on a weekly basis.

Mr. de Blasio’s comments came as nationally several organizations — including various hospital systems, schools, the city of San Francisco and professional football — took steps to require vaccinations.

The National Football League on Thursday announced a penalty that will ideally incentivize players to get vaccinated. The commissioner, Roger Goodell, sent a memo to all 32 teams saying that players who refuse to receive a Covid-19 vaccine may risk their teams forfeiting games if they test positive and cause an outbreak.

While the league has not officially mandated that the players be inoculated, the steep penalties are the strongest stance the football league has taken regarding the vaccine during the pandemic, and it further makes life difficult for the unvaccinated.

Vaccines remain effective against the worst outcomes of Covid-19, including from the Delta variant, and experts say breakthrough infections in vaccinated people are so far still relatively uncommon. But the average pace of inoculation has decreased by more than 80 percent since mid-April, and less than half of the country is fully vaccinated, according to federal data.

Dr. Rochelle P. Walensky, director of the Centers for Disease Control and Prevention, recently warned that “this is becoming a pandemic of the unvaccinated” and that the United States had reached a “pivotal point.”

Nationally, new cases, hospitalizations and deaths remain at a fraction of their devastating winter peaks. But rising cases have led to a steep rise in hospitalizations in some spots around the country where people have been slower to get vaccinated, a predicament experts hoped might be avoided because the people contracting the infection tend to be younger and healthier.

Hospitalizations are trending upward in 45 states, and some health care centers in portions of the Midwest, West and South are struggling. Florida has recently seen the most hospitalizations for Covid-19 since the start of the pandemic.

The Biden administration has pursued multiple strategies to get more people vaccinated and focused on more personalized efforts to reach those who have not gotten shots as that pool has shrunk. Now, local and state officials, sports leagues, businesses and school and hospital systems have to determine whether they will require people to be vaccinated.

The three vaccines for use in the United States are available under emergency use authorization from the Food and Drug Administration. At a town hall in Ohio on Wednesday President Biden said that he expected the F.D.A. to give final approval for the Covid-19 vaccines “quickly,” perhaps as soon as the fall, though he said he was not intervening in the decision of government scientists. Many medical professionals have pushed for the final approval, which they say could help increase uptake of the vaccines.

Indiana University faced a lawsuit after it instituted a vaccine requirement, but on Monday a federal judge ruled that its mandate could stand. And many hospitals and health care systems around the country have instituted mandates, from academic medical centers like Yale New Haven to large chains like Trinity Health, a Catholic system with hospitals in 22 states.

“We were convinced that the vaccine can save lives,” said Dr. Daniel Roth, Trinity’s chief clinical officer. “These are preventable deaths.”

Reed Abelson and Dan Levin contributed reporting.