What’s the best incentive for a COVID-19 vaccine? Here’s what this new study says

Guaranteed cash incentives for COVID-19 vaccination slowed the decline in vaccine rates by half at the clinics they were offered, North Carolina researchers concluded in a study published Monday.

The study, authored by researchers from the N.C. Department of Health and Human Services, North Carolina Central University and the University of North Carolina at Chapel Hill, analyzed vaccination rates at select sites in Mecklenburg, Guilford, Rowan and Rockingham counties.

These sites, from May 26 to June 8, offered $25 to anyone who took the vaccine or to anyone who drove someone to get vaccinated. The sites were selected by DHHS.

There was no limit on how many times a driver could drive someone for the cash offering, but they only got $25 for each visit, even if they drove multiple people.

The study, published in the Journal of the American Medical Association, found that from June 2 to June 8, vaccination rates at the selected sites decreased by 26% from the baseline period of May 12 to May 25.

But it was half the drop that other sites saw.

At sites in the rest of the four counties, vaccination rates decreased by 51%. In the state as a whole, the drop rate 49%.

At the time, there had been a weeks-long statewide and nationwide drop in vaccination rates.

Noel Brewer, professor of health behavior at the UNC Gillings School of Public Health and one of the authors of the study, said in a press release that the results build on 70 years of psychological research.

“Rewards are most effective when delivered immediately after the behavior,” he said.

There were some limits to the study though.

A week-to-week comparison from the week of April 28 to May 11 to the week of May 12 to May 25 showed a 46% increase in vaccination at the selected sites. This was before the cash incentive program started.

At other clinics in the counties, vaccination went down 10%. Statewide it went up 2%.

Brewer told The News & Observer the increase could have been due to the selected sites being better equipped for vaccination in general. He said the state chose sites they thought would be able to best implement the program.

The study itself concludes that since the sites were not randomized, the causal effects between guaranteed cash incentives and vaccination are preliminary.

But Brewer said the results still speak to the program’s effectiveness as vaccine rates still dropped by half at the select sites when statewide rates were dropping.

During the two-week program at selected clinics, 2,890 vaccine recipients received the $25. Among drivers, 1,374 received the cash offering.

Vaccination barriers

Among vaccine recipients surveyed at the select sites, 41% said that the guaranteed cash was an important reason for vaccination.

They were more likely to say the cash was important if they were non-white and had an annual income less than $40,000 a year.

Of those surveyed, 9% said they wouldn’t have gotten vaccinated without the cash offering, and another 15% said they waited to get vaccinated until they found a clinic offering incentives.

Having someone drive them to the clinic was important for 49% of those surveyed, especially if thy were non-white and had low income.

The researchers suggested that small financial incentives be considered as a way to promote equity in vaccine rollouts. They said among the hundreds of millions being spent on COVID-19 vaccine efforts, guaranteed cash incentives should receive more investment.

“There are still people out there who have not gotten vaccinated because they have practical barriers. They can’t take time off work. They need daycare for their kids. There are transportation problems. They know that they would have to take a day off because the next day, they might be really sick and they just can’t afford that,” Brewer said in an interview.

More effective than other incentives

Another recent JAMA study found that North Carolina’s $1 million vaccine lottery over the summer, along with those in other states, had virtually no impact on vaccination rates, The News & Observer reported last week.

Brewer said this is because psychological research indicates that incentives that are uncertain to be received, like cash prizes from lotteries, aren’t as enticing as guaranteed cash.

“The state lottery was always a bad idea,” Brewer said. “The guaranteed cash incentives were actually well done.”

“I would far rather see all of the lottery money put toward guaranteed cash payments, it would be much more effective,” he said.

As of Friday, 55% of North Carolina’s total population and 64% of those eligible, ages 12 and up, are fully vaccinated.