For the first time he is implementing mandatory testing or proof of vaccination, CBS2's Natalie Duddridge reported Wednesday.
The new order begins Aug. 2 and will affect staff at 11 public hospitals.
"Enough is enough, we need our health care workers to be vaccinated. It's getting dangerous with the Delta variant. So, I think it's time to do something different," de Blasio said.
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The mayor said from now on if you're not vaccinated and work at a public hospital, you will have to take a COVID test each week.
"Up to now, things have been entirely voluntary. They are no longer voluntary. You have two choices. The better one is to get vaccinated," de Blasio said.
City Health Commissioner Dave Chokshi broke down the details at Wednesday morning's daily briefing.
"Proof of vaccination or a negative test will be requested from all of our clinic-based staff. That means nurses, doctors, social workers, custodians and registrars," Chokshi said.
Stats show 30% of hospital workers still aren't vaccinated. NYC Health + Hospitals says only 60% of its employees have been vaccinated.
The mayor stopped short of mandating front-line health care workers get the shot, at least for now.
The biggest health care workers union said it opposes mandatory vaccinations, but does highly encourage vaccinations in general.
New Yorkers have mixed feelings.
"The choice of the individual. I don't think anybody should be forced into it. I don't," one woman said.
"Yes, absolutely. Nurses and doctors, required to have a vaccine? Absolutely," another woman said.
"It is their choice. You make the choice, you suffer the consequences," a man said.
Watch Natalie Duddridge's report --
"I think we're overdue for getting mandates," said Dr. Arthur Caplan, a medical ethicist at NYU.
Caplan has a strong stance that if you don't get vaccinated and do get sick, you should volunteer to go to the end of the line for medical care.
"Strains are coming back. It's time to stop worrying about the rights of the unvaccinated and start taking seriously the rights of the vulnerable," Caplan told CBS2's Jessica Layton.
The mayor was asked several times at Wednesday morning's briefing if he would expand the new test or vaccination policy to other city workers, like police or teachers. He said not yet.
"We're going to look at all of those things. Right now, again, we have a clear sense that we had to get started in the most important place, that's our health care workers," de Blasio said.
Mark Levine, chair of the City Council's Health Committee, said he wants to see the city adopt more measures.
"I think we should follow the lead of the other cities, like Los Angeles, that are asking people when they are in those kind of crowded indoor spaces, when there's no screening for vaccination, to put their masks back on," Levine said.
For now, the mayor says he has no plans to once again ask people to put masks back on inside.
"A mask is like a pea shooter and the vaccine is like a cannon. The vaccine is what actually wins. The vaccine is what actually stops the Delta variant," de Blasio said.
If health care workers do not comply with the new orders, officials say they will be suspended without pay.
CBS2's Jessica Layton contributed to this report.
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