The behavioral economics of COVID-19 vaccines

Gabriel Perna | September 29, 2021

Two-thirds of the U.S. population eligible for a vaccine have gotten at least one shot, according to the most recent numbers from The New York Times 

Vaccine mandates are likely going to be the method that push those numbers upward. On September 9, 2021, President Biden announced a new federal vaccine mandate, which requires employers with more than 100 workers to ensure their employees are either vaccinated or tested for the virus weekly. He also mandated those who work at health facilities that take Medicare or Medicaid will have to be vaccinated as well.  

While those mandates have already received legal challenges, the announcement confirms what Jessica Saleska and other behavioral economists have said about the most effective strategy to get the remaining one-third of Americans to take the COVID vaccine. 

“Vaccine mandates are massively effective,” says Saleska, Director of research at Radicle Science. “Even before COVID, mandates have one of the most effective methods to increase childhood vaccination rates, with schools requiring them. Even with outliers for religious exemptions or other reasons, that’s still only a minority of people. Most public health experts are strongly in favor of mandates. The question is if that would cause backlash. It could, but in the past with childhood vaccinations and flu vaccines, which are mandated by universities, it still gets implemented and people still accept it.” 

This will be put to the test across the country as numerous states, health care organizations and employers have reached their vaccine mandate deadlines. While some places, such as Lewis County General Hospital in Lowville, N.Y, have seen a negative impact from vaccine mandates causing workers to resign, most evidence thus far suggests that threats to quit never come to fruition. According to MarketWatch, Houston Methodist Hospital required its 25,000 workers to get a vaccine by June 7. It went from 15 percent unvaccinated to 2 percent—and only 153 workers were fired or resigned. United Airlines CEO Scott Kirby said fewer than 10 employees quit over the company’s mandate 

But even with that being the case, James Kwak, a Professor of Law at the University of Connecticut School of Law and a noted economist, says that organizations who have been afraid to implement a mandate over potential labor shortages are probably thankful to the Biden administration for the cover, particularly those in areas with a strong anti-vaccine contingent. “Some companies have been willing to take the political heat, but a lot of these companies don’t want to become targets [from the anti-vaccine community],” Kwak says.   

Vaccine lotteries strike out 

Regardless of the worker shortage issues that may derive from vaccine mandates, it is still a more effective method than other efforts to increase vaccination rates, experts say. Sean Ellis, Research Project Manager with the Behavior Change for Good Initiative at the University of Pennsylvania, says that nudges and incentives don’t seem to work as well. He was part of a team that created a vaccine lottery system, doling out cash prizes to increase vaccination rates across Philadelphia. They made every resident of Philadelphia eligible, but only those vaccinated could collect their prize. 

“If you weren’t vaccinated, you wouldn’t be able to collect the prize. People knowing this would anticipate the feeling they might have if they won but weren’t able to collect the prize and that would motivate them to get vaccinated,” Ellis says. Unfortunately, the vaccine lottery didn’t move the needle on increasing vaccination rates. “All those who would be incentivized were already nudged into getting the vaccine. Earlier in the pandemic, these incentives could have certainly worked, and they could help close the gap for people who got one dose of the vaccine, but not a second one.”  

It wasn’t just the vaccine lottery that didn’t work in Philadelphia. There were also free tickets to sporting events and free coffee, but James Garrow, Communications Director for the Philadelphia Department of Public Health, told NPR that none of them led to a big jump. Ohio held its own vaccine lottery program and it also failed to move the needle in the long term or help the state reach its goals. 

Other incentive plans  

While vaccine lotteries may not be effective, there are non-mandate strategies that can work well, says Saleska. For instance, she says making vaccines incredibly convenient and the entire experience frictionless can boost vaccination rates among the “fence sitters,” people who aren’t strongly anti-vaccine but may be holding off for various reasons. 

“A lot of times friction in the decision-making process—friction in making the appointment, friction in going to the appointment—can inhibit people from doing what you want them to do. If you make it very easy, you’ll see movement of the needle among fence sitters. Making vaccines easy to get, making them free, reminding people of this a lot are all really important,” Saleska says. “There have been a lot of studies on flu vaccines that when people at their workplace, you give people an hour to get a flu vaccine and put a vaccine truck outside their office, this causes a huge uptick of vaccines.”  

When it comes the decision-making process of each individual and the biases and heuristics people employ, public health has not recognized that. The role of behavioral science is how do you deliver this information in a way that’s more effective than simply providing recommendations?

Jessica Saleska, Radicle Science

Ellis agrees with this notion. He says making vaccines easy to access should be a goal of health care leaders along with strong communication strategies around its safety. There are various studies around the importance of messaging. One research effort, in the Journal of Health Communication, found that messages that highlighted the potential health problems from not getting a vaccine were slightly more effective than the positive “gain” framing that stresses the benefits. It also found that people were motivated to get vaccinated based on individual framing, rather than messages focused on the collective good.  

Health insurance companies and employers could incentivize people to take vaccines, says Kwak, through their wellness programs. Kwak says that if COVID-19 vaccine requirements were added to wellness programs, employers and insurers could build in a $100 monthly reduction in premiums. In some cases, employers are creating a premium surcharge, a tactic used with smokers, that would penalize unvaccinated workers in their monthly premiums. Delta Airlines did this and said it caused 20 percent of its unvaccinated workers to get the shot. 

“You want to set the dollar amount at a level that is affordable but will send a signal to people that need to get the shot. People’s responses to financial incentives are not linear. At certain levels, we don’t notice them. At certain levels, we start to notice them. It has to be at a level people will notice, but not too high,” says Kwak.  

He adds that insurance companies negotiating group health plans with large employers could work incentives into the agreements. Also, employers and insurers could set up workplace vaccination sites. Still he admits, “I don’t know if it’s the best method as opposed to a blanket mandate.”  

Behavioral economics for future public health crises  

Back in March, Saleska wrote a paper in Translation Behavioral Medicine that foretold the struggles that were to come with vaccination efforts. She wrote, “both the unusual speed of vaccine development and reports about side effects,” were causing many people to distrust the vaccine. She also noted that new vaccines, throughout history, have always had issues when it comes to gaining public trust.  

“When I wrote that back in March, about half of Americans were vaccine hesitant. So, we’ve actually made inroads in people’s willingness to get the vaccine. But the lack of adoption among large swaths of people is not actually that surprising. If you look at the history of vaccines, there has always been a lot of hesitancy,” says Saleska. “What’s distinguishing about the COVID-19 vaccine is the amount of misinformation about it on the internet. You see more strength around anti-vaccination movements because of the internet.” 

Saleska says the anti-vaccine movement around COVID is more hostile than others in the past. This challenge has created numerous initiatives—applications of behavioral economics—to increase vaccination rates, the lessons of which can help health care leaders take on future public health crises.  

“The lessons we’re learning currently—which range from very gentle nudges to mandates—are certainly going to inform  flu shots in the future. I recently read that the largest share of American adults that have ever gotten the flu shot is only 45 percent in a single season. There’s a long way to go to get people to get their flu shot and other vaccines,” Ellis says. “These lessons can also be used to encourage Americans to go to the doctor more often for preventive reasons.” 

In terms of behavioral economics, Saleska says messaging is the most important area that the lessons of COVID can be used for future public health crises. Public health experts have struggled, she says, to disseminate recommendations.   

“From a public health standpoint, there is an underlying assumption that if we give people the information, they are going to make the right decision. If we give them the pros and cons, they’ll weigh those and pop out with the right behavior. A lot of the times, though, that’s not the case,” Saleska says. “When it comes the decision-making process of each individual and the biases and heuristics people employ, public health has not recognized that. The role of behavioral science is how do you deliver this information in a way that’s more effective than simply providing recommendations?”  

About the Author

Gabriel Perna, Senior Manager, Digital Content

Gabriel Perna is the Senior Manager of Digital Content at Health Evolution. He brings 10+ years of experience in covering the intersection of health care and business. Previously, he was at Chief Executive, Physicians Practice and Healthcare Informatics. You can reach him via email at or on Twitter at @GabrielSPerna