Ohio changed the game for vaccine incentives when the state introduced the Vax-a-Million campaign. Now, 10 other states and some big companies have raised the stakes to boost vaccine rates.

Companies like Kroger, United Airlines and CVS are leaning in big, but beware -- experts see a risk that could get sloppy copycats in big trouble. Ken Katkin, a law professor at Northern Kentucky University, said if customers have to go in the store and buy anything, the company’s legal sweepstakes becomes a liability.

"They have to be careful to make sure that it's absolutely free for anybody to enter," Katkin said. "Because that would be gambling, which they're not necessarily licensed for, right. So a sweepstakes or a lottery that costs nothing for anyone to enter isn't considered gambling. It's legal for them to do that."

CVS plans to offer free cruises, vacations, gift cards, and with help from Procter & Gamble, a trip to the Super Bowl. United Airlines is giving away free flights around the world for a year. Kroger is going to give five vaccinated people $1 million dollars and 10 others free groceries for a year. Winners should expect a tax, though, even on the groceries.

"Any prize in excess of $600 will require tax reporting on a 10-99," said Bob Salyer, a tax instructor at Northern Kentucky University.

The big prize potential seems to be working in some areas. Vaccine rates jumped 33% in Ohio the week after the state announced its million-dollar incentive lottery, according to an Associated Press analysis.

"I think whatever it takes to get people vaccinated, I think it's great,” said Sheri Wilson of Lawrenceburg. "I don't know where that money is coming from, but it's a great incentive.”

Jared Reynolds of Lawrenceburg is not so fond of the idea and hopes it doesn’t pop up in Indiana.

"I'm glad that Indiana doesn't have anything like the million-dollar vaccine," Reynolds said. “I wish that money would be added more toward schools. There's starving veterans. There's starving people out there. Give them groceries. I think we need to take care of those people as well."

Kentucky Lottery gave an incentive to Kentuckians by giving free $1 Cash Ball plays to those who got vaccinated from May 10 to 21 at Kroger or Walmart locations. The potential earnings topped out at $225,000.

Ohioans can opt in to the Ohio Department of Health’s vaccine lottery starting Tuesday, department head Stephanie McCloud announced Monday morning. Anyone who hopes to win the sweepstakes, which will award $1 million each to five vaccinated people in the state, must register online or over the phone to be eligible for a prize.

Gov. Mike DeWine announced the project on May 12 but provided few details; at the time, it was unclear whether all vaccine recipients in the state would be automatically entered or be required to enter themselves. The opt-in system sidesteps privacy concerns by requiring entrants to voluntarily give the state permission to investigate their vaccine status, McCloud said.

The Ohio Vax-a-Million lottery site had been set up with the help of the Ohio Lottery Commission by the time McCloud spoke on Monday, although it won’t open to registrants until 8 a.m. Tuesday.

Registrants can also sign up over the phone at 1-833-427-5634.

To register, you must be:

• An Ohio resident
  • McCloud said the threshold for residency used in the contest will be the same one used for voter registration and acquiring an Ohio driver's license.
• At least 18 years old
• Vaccinated with at least one shot by the time of the week’s drawing

Hopefuls only need to register once, McCloud added. Winners’ names will be removed from the statewide pool after each drawing, but non-winners' names will go right back in.

“This is a bold initiative and we are so proud to bring it to Ohioans to hopefully turn the tide on COVID,” McCloud said.

The first drawing will take place May 24; after two days, during which the state will verify the winner’s vaccine status, the winner’s name will be announced May 26.