We’re starting to reach a critical stage in the vaccine rollout. Less than half of U.S. adults have received one dose of a COVID-19 vaccine and only 35% are fully vaccinated. And some experts are saying it’s unlikely we’ll ever reach herd immunity. Now local governments are partnering with businesses to offer incentives, free stuff in exchange for getting the vaccine. But do these programs work? Gretchen Chapman, who studies vaccine behavior at Carnegie Mellon University, said incentives usually work on people who only need a little push. And researchers don’t know if they’ll work for the COVID-19 vaccine like they have for others. “We’re at the point where there’s going to be no one intervention that’s going to meet everyone who hasn’t vaccinated yet,” she said. Read more at Marketplace.