The New York City Fire Department announced Sunday that 61-year-old Joseph Ferrugia is its first active firefighter to have died of COVID-19.

He is the 13th member of the FDNY to die of coronavirus.

“This horrific illness has taken far too many lives, and now it has killed a man who bravely served New Yorkers for three decades," Fire Commissioner Daniel A. Nigro said in a statement Sunday. "He ran toward danger his entire career, searching for those trapped by flames and doing all he could to save them. Our entire Department mourns his loss.”

Ferrugia joined FDNY in 1990 and was a World Trade Center first responder, the department said.

FDNY said he is survived by his three adult children and three siblings.

Chicago Public Schools pushed back the return of in-person classes for kindergarten through eighth-grade students by one day as negotiations continue between the city and the Chicago Teachers Union.

While the district and union leadership agree on some items of contention in principle, Mayor Lori Lightfoot said at a press conference Sunday that the union has refused to put those agreements in writing and instead has added more items to the negotiating table that are not related to the public safety issues associated to reopening some classrooms during the COVID-19 pandemic.

Just minutes before Lightfoot was expected to appear in a presser Sunday, CTU sent a series of tweets that hinted there was not going to be a deal just yet.

The mayor said she still expects CPS teachers to show up to their classrooms despite the dispute. Last week she said that if they do not, she would be forced to take further action, but did not specify what that action would be.

The U.S. Centers for Disease Control and Prevention released its latest update Sunday on the country's coronavirus vaccine rollout.

There have been close to 50 million doses distributed around the country, according to the agency's online tracker. Of those doses, 31 million, roughly 62%, have been administered, according to the CDC.

About 25 million people have received their first dose and 5.6 million have received two doses, the CDC said.

A city on Florida’s panhandle put on its Mardi Gras parade as planned, despite its high positivity rate.

Prior to the parade on Saturday, Milton Mayor Heather Lindsay advised residents to take their temperature before attending the event and for everyone who attends the party after the parade and participates in the kid’s zone to wear a mask.

"I would love to focus only on the fun and pageantry of it all because I love Mardi Gras, but we must accept life on life's terms," Lindsay wrote. "Presently we are in the midst of a widespread outbreak of a virus that is not just the flu."

The city currently has a positivity rate of 18%, "well above" the state average of 6.62%, Lindsay wrote. Households affected in Milton reduced from a high of 102 to 90 this week, but the local positivity rate has been as high as 28% and "never lower" than 16%, she added. The population in Milton is about 10,000.

It is unclear how many people attended the event.

Dr. Anthony Fauci, the nation's leading infectious disease expert, spoke about the latest updates on the U.S. vaccine rollout during an interview Monday on ABC News Live.

Fauci, director of the National Institute of Allergy and Infectious Diseases, said that he believes the vaccine will be available to everyone beginning in April, but it won't be until the fall that everyone has actually gotten their shot in the arm.

"It will take several months-May, June, July, August- before you really get what I would consider the herd immunity level, which is an estimate, but I think it's a reasonable estimate, namely getting 70 to 85% of the population vaccinated," Fauci, who is also Biden's chief medical adviser, told ABC News Live.

Fauci said that the timeline is not considering a future approval of coronavirus vaccines developed by Johnson & Johnson and AstraZeneca.

"I think if the J&J or the [AstraZeneca] product comes through with an efficacy that's good enough to be able to be in the mix, that will be very helpful to get things done even sooner than we thought," he said.

Fauci also opened up about an incident where he was exposed to a powder substance that was in his mail last year. The powder was later deemed benign, but only after his security detail put on hazmat suits and sprayed him down.

"It frightened the heck out of my children when they found out about it and my wife too," he said. "I mean, I've decided I'm doing something that might be dangerous but that's it, I chose it. My children did not choose that."

Watch Fauci's full interview with ABC News Live at 7 p.m. and 9 p.m. ET Monday.