Vaccine mandates have been yet another controversial move in the deeply divisive COVID-19 pandemic, sparking lawsuits, protests and warnings of reductions in service.
But data and experts suggest that they are working.
In fact, some organizations saw their employee vaccination rates jump from less than half to over 90%.
James Colgrove, a professor of public health at Columbia University's Mailman School of Public Health told ABC News that he's not surprised with this outcome and predicted that similar workplace orders will follow the same story.
"In general, vaccine mandates work," he said.
While vaccine opponents may appear vocal, medical experts say most are not dead set against the vaccination and need that push brought up by a mandate.
Although Colgrove and other medical experts say the country is in "uncharted territory" when it comes to vaccine mandates for adults, since such orders are rare outside of the health care industry, the signs are pointing to the directives greatly moving the needle in the country's vaccinations efforts.
Jumps in vaccinations after mandates issued
Colgrove said the country has seen the effectiveness of vaccine mandates in our schools, which for decades have mandated inoculations against measles, mumps and other ailments. Mandates for hospital workers have also been shown to prevent outbreaks and mass worker shortages from illness, he noted.
COVID-19's persistence in the U.S. and the resulting worker shortages from sick and hospitalized employees virus has forced many organizations in the country to consider mandates, according to Colgrove.
When the delta variant caused a jump in COVID-19 cases, hospitalizations and deaths among the unvaccinated in the summer, more mandates and mandate-like programs were announced.
Some private companies started to issue vaccine mandates in the summer for their in-person based employees including Google, Tyson Foods, United Airlines and the Walt Disney Company, which is the parent company of ABC News. All of the companies allow exemptions for religious reasons and give deadlines for the fall.
The results from some of those mandates were strong, according to data shared by some companies.
When Tyson announced its mandate on Aug. 3, it said that less than half of its nearly 140,000 employees were vaccinated. When the deadline for the mandate came at the end of October, the food processing company said over 60,000 of its members got their shots and 96% of its staff was vaccinated.
"Has this made a difference in the health and safety of our team members? Absolutely. We’ve seen a significant decline in the number of active cases companywide," Tyson Food president and CEO Donnie King said in a statement.
United Airlines said 48 hours after it announced its mandate, the number of unvaccinated staffers fell from 593 to 320. As of Oct. 27, 99.7% of the airline's 67,000 employees had complied with the mandate, according to United.
"Our vaccine policy continues to prove requirements work," the company said in a statement.
Dr. Sarah Goff, an associate professor of health promotion and policy at the University of Massachusetts, Amherst, told ABC News that organizations are aiming to get their workplaces back in person and have been more willing to issue the mandates.
She also cited the 1905 Supreme Court case Jacobson v. Massachusetts, which ruled that states have the right to issue a public health mandate, and the ruling Department of Justice's Office of Legal Counsel has strong factors behind the mandates.
"There is precedence for vaccines to be legally acceptable, but it's up to the states and the companies," Goff said.
In the public sector, a handful of states announced mandates for their state and local agencies in the summer and fall including Washington State.
Officials from Washington state's health department told ABC News that the percentage of public employees who were vaccinated jumped from 49% on Sept. 6, a month after Gov. Jay Inslee announced the mandate, to 96% on Oct. 18, the mandate's deadline.
New York City shows progress despite protests
New York City came under the spotlight for its vaccine mandate policies. At first, it allowed unvaccinated public employees who weren't in health care or the Department of Education, but on Oct. 20 Mayor Bill de Blasio announced the rest of the city workforce needed to get one dose by Oct. 29 or be placed on unpaid leave. The city allowed for religious exemptions city employees who recently received an mRNA vaccine must show proof of their second dose within 45 days of their first shot.
At the time of the announcement, 84% of the city's workforce had one shot, but several agencies, including the FDNY, NYPD and Sanitation Department recorded less than 75% of their staff, vaccinated, according to data from the mayor's office.
Unions representing the FDNY and NYPD tried to take the matter to court but were denied injunctions before the deadline. Still, the Uniformed Firefighters Association led rallies against the mayor and the mandate contending that vaccinations should be the personal choice of their members.
By the time the mandate deadline came on Oct. 29, vaccination rates among the lagging agencies greatly increased. As of Nov. 7, 86% of NYPD members, 91% of city EMS personnel and 82% of firefighters have had one shot, according to data from the mayor's office.
The FDNY said that some firehouses were understaffed the Monday after the deadline, which Fire Commissioner Daniel Nigro said was from a higher number of firefighters calling out sick. Nigro chastised any firefighters who used their sick days to protest the mandate.
In the end, only 34 police officers were placed on unpaid leave on Nov. 2 and all of the FDNY firehouses were operational on Nov. 5, according to the mayor's office.
Not willing to take the risk
Goff said at the end of the day most people hesitant about getting the vaccine, even those who make a lot of noise about it, would not jeopardize their careers or families.
"You lose your job and it impacts people's livelihood and while there may be some who say they're willing to risk that, they don't," she said.
Goff and other medical experts added that the mandates also reach a wider group of people who aren’t completely dead set against the vaccination.
Colgrove said the increases in worker vaccinations after a mandate tracks with the data on vaccine hesitancy in the country.
While he said there is certainly a group that is completely against getting the vaccine, there are more unvaccinated people who are simply on the fence and haven't had either a strong motivation or good enough messaging to go forward with it.
A survey released on Oct. 28 by the Kaiser Family Foundation said 8% of all adult respondents revealed they would ask for an exemption if presented with such a mandate, and 1% of adult respondents lost a job because of a mandate.
A KFF survey released a month earlier found that two-thirds of unvaccinated workers would not get a shot if their job demanded it.
"When you look at vaccine resistance, the people who are the most opposed often make a very large amount of noise that is at odds with the actual numbers who are against vaccination," Colgrove said.
A strong nudge and a change in messaging
Dr. Kevin Schulman, a professor of medicine and economics at Stanford University School of Medicine and Graduate School of Business, told ABC News, said the mandates positive effect on changing the messaging of vaccines.
Schulman, who has written articles in medical publications on the need for better marketing of the COVID-19 vaccine, said companies have been using their vaccine mandate orders to emphasize their effectiveness more directly with their employees.
For example, United Airlines CEO Scott Kirby and President Brett Hart told their employees that they had a responsibility to their employees to remain safe and prevent flight cancellations.
"It ends up being a story about how do we protect ourselves and how do we get up and flying again," Schulman said. "It sticks with the apathetic population."
Schulman said that company incentives, such as one-time salary bonuses, also helped sway the holdouts.
"Seeing other people around them get the vaccine, and tolerating it and going about their lives will help those groups," Schulman said.
More company mandates likely
Last week, President Joe Biden announced a vaccine employment requirement through a new regulation from the Labor Department’s Occupational Safety and Health Administration (OSHA).
Companies that have 100 or more employees must require unvaccinated members to test weekly or face federal fines starting Jan. 4. Over 100 million employees are affected by this order.
Twenty-six states are suing the administration over the order and a judge in Louisiana issued an injunction on Saturday.
The health experts say the court battle over Biden's plan won't deter organizations from issuing their own mandates, including ones that go further than OSHA's rules and place unvaccinated members on leave.
Colgrove said the need for a strong and healthy workplace and the increased examples of mandates working will compel those organizations to improve their vaccine rates one way or another.
"The more normalized it comes, the more people someone knows someone else who is vaccinated, the more people will comply," Colgrove said. "With any vaccine the longer it's been around the more people get with it."