He said the combination of the Omicron variant and holiday gatherings forced him to take "bold" steps. He's giving businesses just three weeks to make sure their workers are vaccinated.
"We in New York City have decided to use a preemptive strike to really do something bold to stop the further growth of COVID and the dangers it's causing to all of us," he said in an interview on MSNBC.
WATCH: Mayor De Blasio Announces Vaccine Mandate For Private Companies
De Blasio said the city will release specific rules on Dec. 15, before the mandate takes effect Dec. 27. He said it will apply to in-person employees, but would not provide any details about enforcement. He also said there will not be a weekly testing option.
"Vaccines work, and vaccine mandates work, particularly when joined with efforts to build vaccine confidence, provide incentives, and improve access, as we have in New York City," said city Health Commissioner Dr. Dave Chokshi. "We've seen this with our health care workers, school staff and public employees. Now it's time for the private sector to step up and follow suit."
"Getting the unvaccinated vaccinated is critical to getting our control. We know that that will not happen voluntarily," Dr. Zeke Emanuel added. "That's where mandates come in. We know that no one likes to be required to do something. We all like to be given our choice. We are, after all, Americans, where freedom of choice is essential. But when we have this collective issue that we all have to get vaccinated to protect everyone, we do need to have mandates."
New York City previously imposed vaccine mandates for city workers, but this will be the first-of-its-kind for the private sector -- impacting 184,000 businesses. So far, 94% of municipal employees have gotten their shots, officials said.
"This would be my advice to mayors, governors, CEOs all over the country. Use these vaccine mandates," de Blasio said. "The more universal they are, the more likely employees will say, 'OK, it's time, I'm going to do this,' because you can't jump from one industry to another or one company to another. It's something that needs to be universal to protect all of us."
Some are raising questions about whether it will slow the return to Manhattan's Central Business District, which is crucial to the city's economy.
"In the Bronx, with 15% unemployment, 28% of residents will no longer be able to work on Dec. 27, including 44% of Black young adults, as a result of de Blasio's vaccine mandate for the private sector," Staten Island Councilman, the incoming Republican minority leader, Joe Borelli tweeted.
CBS2's Marcia Kramer asked de Blasio if he thinks the mandate will mean fewer workers will give up telecommuting and return to offices.
"I think you're going to see a lot of people embrace it. You're going to see a lot of people make the decision it's time to get vaccinated," he replied. "I really think we're going to see this actually help, ultimately."
"[Eric Adams] has always said he understands right now there are urgent threats facing our city and the mayor's job is to protect New Yorkers. That's my responsibility up until the very last minute," said de Blasio.
"The mayor-elect will evaluate this mandate and other COVID strategies when he is in office and make determinations based on science, efficacy and the advice of health professionals," Adams told CBS2 in a statement.
Hochul did not respond to CBS2's request for comment.
New York State Attorney General Letitia James, who is also running for governor, said she supports a "vaccine mandate with a testing option."
"A mandate alone won't get us out of crisis, particularly when it's implemented without input from employees and employers. Science tells us we need everyone to wear masks in public settings; accessible at-home testing; and real health outreach to our communities," James said in a statement. "This cannot be done municipality to municipality. New York state must finally lead."
- New York State book online here or call 1-833-NYS-4-VAX
- New York City book online here or call 877-VAX-4NYC
- Track NYC vaccinations by zip code
- Nassau County more info here
- Suffolk County more info here
- Westchester County more info here
- New Jersey book online here or call 1-855-568-0545
- Connecticut book online here
Meanwhile, Borelli is promising to sue to stop the mandate. The Brooklyn Chamber of Commerce said it could mean layoffs this holiday season, and the Partnership for New York City's Kathryn Wylde told Kramer she wonders if de Blasio is politicizing COVID as he is almost out the door, and because he wants to run for governor.
Randy Peters, the head of the Brooklyn Chamber of Commerce, called the new mandate virtually unenforceable.
"There are 62,000 small businesses in Brooklyn, alone. It sets up problematic confrontations between employers and staff, which could result in layoffs around the holidays that would be incredibly unfortunate," Peters added.
"I think that the timing of the mayor's announcement and the failure to consult with the business community only makes a very nervous, bad situation worse. It makes it tougher for all of us," Wylde added.
Tyler Hollinger owns Festival Café on the Upper East Side. He told CBS2's Cory James the restaurant that he opened in the middle of the pandemic is facing unnecessary challenges.
"It's clear that the politicians are playing politics with small business," Hollinger said.
Sean Hayden, who owns multiple restaurants in the city, including Valerie in Midtown, said he does not have a problem with the decision.
"We were closed here for 14 months and I don't want to go back to that, and I feel like customers that are coming here spending good money and they want to know the status of the people who are serving them," Hayden said.
However, those from other countries may face some setbacks.
Andrew Rigie, with the New York City Hospitality Alliance, shared an email from a Belgian family who said their 6- and 9-year-olds are not able to get vaccinated in their country.
In a statement, Rigie said, "Given the rapidly approaching holidays and considerable impact of the Dec. 14 deadline, the proposal should be delayed until next year."
Some of the smaller mom-and-pop businesses that deal directly with the public said they see nothing wrong with the mandate.
"I don't see a problem. I am vaccinated. I believe it's a responsibility everybody should have," Jay Cardinal said.
When asked if she thinks the mandate will affect other businesses, store owner Kerry Colley said, "I hope it does. I think there's a level of responsibility being business owners. We have to protect ourselves, employees, and our customers."
"That's a good idea. It's good for everybody to be vaccinated," Joachim Anikgomes added.
- Complete COVID Vaccine Coverage
- Vaccination Sites In New York City | Call 877-VAX-4NYC
- Track NYC Vaccinations By Zip Code
- Find NYC Testing Site Near You
- Check NYC Testing Wait Times
- CDC'S COVID Vaccine FAQ
- CDC's COVID Tracking Map By County
- Resources: Help With Unemployment, Hunger, Mental Health & More
- Remote Learning Tools For Students And Parents At Home
This comes as New York City is also extending the vaccine mandate for indoor dining, fitness and entertainment to include children ages 5 to 11. Starting Dec. 14, kids in that age group will be required to show proof of at least one shot.
Then on Dec. 27, people ages 12 and older will need proof of both doses, except for those who received the Johnson & Johnson vaccine.
Also on Dec. 14, children ages 5 to 11 will have to have at least one shot to participate in "high risk" extracurricular activities, like sports, band, orchestra, and dance.
Dr. Chokshi said case rates are currently highest among 5- to 11-year-olds and encouraged parents to get their kids vaccinated.
CBS2's Cory James contributed to this report, which first appeared on Dec. 6.
for more features.