Vaccination rates for COVID-19 in the United States remain low, stalled at just over 50 percent of adults, even with three different medicines available for free.

To convince more people to get the potentially life-saving jabs, some states have started to offer financial incentives, like million-dollar lotteries. A new pilot program in North Carolina suggests there may be an even better way.

A lottery only ends up benefitting a few lucky people, which means most who enter don't get repaid for lost wages, transportation, or childcare.

So what if we simply cover those costs? That's something researchers and politicians have been considering, although the risk of 'vaccine coercion' is something ethicists have been mulling over as well.

Still, this isn't a new idea. In the past, financial incentives have helped the uptake of the human papillomavirus vaccine (HPV) in the United Kingdom. And earlier this year, some survey experiments in the US found a third of those who were unvaccinated would be convinced to get a shot if they were given a cash payment, with benefits increasing as the money went from a theoretical $25 to $100.

Results from a two-week pilot program in North Carolina suggest the incentives could work in the real world too.

The 'quasi-experimental' study was started in four counties of the state, where some clinics guaranteed a quick $25 cash card to anyone who arrived to get their COVID-19 vaccine or brought someone else to the clinic for their first dose.

In total, the clinics paid out nearly 3,000 of these cards to 1,374 people in the two weeks. Compared to clinics in the same counties that didn't offer financial incentives, those that did seemed to have more vaccine recipients during the study period.

Clinics that were not part of the pilot program saw first-dose vaccinations decline by nearly 10 percent in the two weeks of the study, whereas those that were part of the pilot program saw a 46 percent increase.

When researchers surveyed some of those patients who participated in the program, they found a significant number had been motivated by the money.

Of all 401 vaccine recipients surveyed, 41 percent said the cash card was an important reason for their vaccination, and this was especially true among Hispanic people, Black people, and those with lower incomes.

Nearly 10 percent of those surveyed said they wouldn't have even bothered to get vaccinated if the cash card wasn't available, and 15 percent of respondents said they waited to get their jab until they found a clinic that had a cash card or other incentive.

Older individuals and those with lower incomes were more likely to have been driven to the vaccination clinic by someone who then received a cash card for their services.

"With vaccination rates lagging in areas with higher social vulnerability, small financial incentives should be considered in conjunction with other equity-promoting strategies," the authors argue.

"The social incentive of cash cards for drivers may also encourage people to help get their friends and family vaccinated, a powerful motivator for those undecided about vaccination."

After all, not all unvaccinated Americans are strongly against vaccines. Some are vaccine hesitant, meaning they are actively questioning whether or not to get the COVID-19 vaccine. While many others are apathetic, meaning the vaccine isn't even on their minds.

In this particular case, researchers think financial incentives could help turn indifference into enthusiasm.

Young people who aren't afraid of the COVID-19 virus, for instance, might be motivated by some easy cash. Older adults struggling to find a time to get vaccinated could use the money for childcare.

And those who have experienced discrimination within the medical field and who generally ignore medical topics like vaccination could start paying more attention to the idea of vaccination.

"If you're not thinking about getting a vaccine and then there they are at the local baseball game or swimming pool or airport, and they're giving out free pizza and a T-shirt, well, now I'm interested," marketing researcher Stacy Wood from NC State University explained on a recent podcast.

The pilot program in North Carolina is limited in what it can tell us about the success of vaccine motivation. The study was based in the real world, which makes it hard to compare with a control group.

It's also hard to say how well this program would work in other parts of the country, seeing as it was only introduced in four counties of one state.

That said, the initial findings suggest this is a promising strategy for increasing COVID-19 vaccination rates, and one that we should be considering going forward, especially for vaccine apathy which seems to be more of a problem than we thought.

"With hundreds of millions of dollars being spent to accelerate COVID-19 vaccine uptake, these study findings suggest that this strategy for increasing vaccination merits greater investment," the study authors conclude.

The study was published in JAMA Internal Medicine.