The ongoing debate around mandatory Covid-19 vaccines has created angry employees and confused leaders.

For the majority in both public and private sectors, enforced policy and vaccine passports are becoming the rule rather than the exception. Google, Netflix, Disney, Walmart, and Facebook, among many others, are adding themselves to the growing list of employers requiring employees get vaccinated or risk being terminated.

Legal and ethical precedence makes it clear that public safety trumps individual freedoms in such cases, meaning that employers will be required by the courts to abide by mandatory vaccine policies. But with estimates suggesting about a third of people oppose vaccine enforcement, it's clear that not everyone is on board.

Leaders will inevitably face issues around compliance and trust -- leading to the added risk of employees feeling disgruntled and disenfranchised. So, what can leaders do? 

They need to think about their communications very, very carefully.

How You Communicate Makes All the Difference

How we communicate strategically goes a long way in influencing people's behaviors, especially when it comes to situations that are infused with emotion. 

Fortunately, behavioral science has a lot to say on the matter.

Behavior change communication (BCC) theory is the development of communication and messaging strategies to promote positive behaviors in individuals and groups. When it comes to enforcing vaccines in the workplace, leaders need to think very carefully about what they say and how they say it to get as many people as possible on board.

Here are four strategies from BCC theory that leaders can leverage for their own messaging.

Think About the Framing of the Message

In making the benefits of vaccines known to people, there are two motivational frames leaders need to think about. The first, called avoidance motivation, will evoke emotions of fear, contempt, or disgust in people to get them to comply with vaccine mandates. In other words, it's about scaring people into getting the vaccine.

Railroad service Amtrak took this avoidance tactic in its recent communications to its 17,500 employees. CEO Bill Flynn wrote, "Covid-19 vaccines are proving effective against the current surge of variants, especially at preventing severe disease, hospitalization, and death." Death is the ultimate avoidance motivation.

Walmart CEO Doug McMillon took a similar approach. In an internal memo he started by saying, "As we all know, the pandemic is not over, and the Delta variant has led to an increase in infection rates across much of the U.S." 

In contrast, the second framing, called approach motivation, will evoke emotions of hope and optimism in people to encourage adoption and compliance. Delta Airline's messaging attempts to assuage employee's concerns by pointing to the good outcomes. "Vaccines are safe, effective, and essential to the future of the airline and our world."

Generally, approach frames are more effective than avoidance frames. While the latter can work in some cases, the constant vigilance and negativity bias can lead to enduring stress and fatigue in individuals.

Appeal to Unity and Togetherness

The other strategy is for leaders to remind people that "we're in it together." Master of persuasion Bob Cialdini talks about unity as a core driver in how to influence other people's behaviors. 

Consider Equinox, SoulCycle-owner and luxury fitness company. It announced its proof of vaccination required for both members and employees and invited other companies to join them in the cause. "We encourage other leading brands to join us in the effort to best protect our communities." 

Google's "take care of each other" collective attitude also reinforces the idea of community and togetherness. The tech giant's CEO Sundar Pichai said, "I'm proud of the way we continue to take care of each other while helping people, businesses, and communities through these difficult times."

Give Human Insight Into the Rationale Behind the Decision

Research in behavioral science has shown that when it comes to appeasing both sides in a controversial, morally laden topic, it helps to show how you made the decision, and how all factors were carefully considered. 

United Airlines CEO Scott Kirby is a good example of this. He leans in on the use of personal pronouns throughout the messaging, and he explains his rationale: "And so, for me, because I have confidence in the safety of the vaccine -- and I recognize it's controversial -- I think the right thing to do is for United Airlines to require the vaccines and to make them mandatory."

Washington Post CEO Fred Ryan did something similar. "Even though the overwhelming majority of Post employees already provided proof of vaccination, I do not take this decision lightly ... I believe the plan is the right one."

And Finally, Don't Offer Cash Incentives

Tyson Foods has been incentivizing its frontline staff to get vaccinated by offering up to four hours additional pay and $10,000 cash lottery prizes. On the surface these may seem like an effective strategy. After all, who doesn't like a little extra cash? 

But research suggests that cash incentives aren't that effective, and worse still can lead to a backfiring effect. Getting people on board with vaccine passports and mandatory immunization should be a very human process of engaging with people and building trust.