A remarkable achievement took place this week.

According to new figures from the Centers for Disease Control and Prevention, more than half of our nation’s adults (that’s 129 million people) have become fully vaccinated against COVID-19.

“This is a major milestone in our country’s vaccination efforts,” White House senior COVID-19 adviser Andy Slavitt said. He could hardly be more correct. A year ago, there was nothing that could be done to fend off the virus. Now, more than 164 million Americans, adults and children, have received at least one dose.

As encouraging as these numbers are, they don’t address a major, ahem, sticking point: Many millions of the adults remain unvaccinated — including many who work in the senior living field — have no intention of ever getting a shot.

To senior living operators, that is — or at least should be — a very troubling reality.

So what’s to be done?

A basic principle of economic analysis is that people respond to incentives. And a growing number of states are warming up to the concept.

Most recently, Maryland, New York and Oregon announced plans to give prize money to vaccinated residents. They are following in the steps of Ohio, which began a lottery-type program in early May. Given new Treasury Department guidance endorsing such schemes, it’s a safe bet more states will follow.

Yet a major roadblock still remains: mistrust. A substantial number of adults simply don’t believe the vaccine is right for them. Some don’t trust the people that find, manufacture and distribute the vaccines. Many more simply don’t put much faith in the state or federal officials egging them on.

If their suspicions are to be overcome — and perhaps they cannot — then we need to take a more compassionate and understanding view of why the mistrust exists. Historical or other contextual reasons may be fueling concerns. Some may not understand how a drug could come to market in less than a year, or that the groundwork for developing COVID-19 was established years ago.

Free money, free donuts, free travel and other lures may motivate the fence sitters. But they are unlikely to convince those who see COVID-19 vaccinations as fundamentally wrong. To be sure, great progress has been made against the pandemic. But in some ways, the hard part is just getting started.