Want tickets to the Super Bowl? An all-expenses-paid cruise through the Caribbean? A check for thousands of dollars?

Get a COVID-19 vaccine, and you may win one of those — or a host of other rewards offered to induce people to get their shots.

With about 41 percent of the U.S. population fully vaccinated, officials in public health and the private sector have begun turning in recent weeks to tangible prizes to incentivize remaining Americans to do so.

Ohio rolled out a $1 million weekly lottery drawing for vaccinated residents. Companies from Target and Wyndham Hotels and Resorts to the dating app Hinge have pitched in prizes to various vaccine sweepstakes.

Last week, President Biden’s administration announced more incentives, including free child care while parents are vaccinated — and a free pint on Independence Day. Anheuser-Busch promised free beer on the Fourth of July if 70 percent of the nation’s adults have gotten at least one shot by the holiday, which is President Biden’s goal.

“That’s right, get a shot and have a beer ... to celebrate the independence from the virus,” the president said on June 2.

But do all these incentives actually work? And what can Virginians expect?

The commonwealth “is certainly considering what resources it wants to put into incentivization,” Dr. Danny Avula, vaccine coordinator for the Virginia Department of Health, told The Virginian-Pilot last week.

Dr. Avula said he’s been in touch with counterparts in other states to monitor what’s working.

North Carolina launched a pilot program offering gift cards to both those who got vaccinated and those who drove others to get a shot, for example. Incentives offered in other states such as lotteries, retirement plan contributions, free hunting licenses — “all of those things are on our radar,” Dr. Avula said.

But he said Virginia wants to wait until more data shows that such efforts provide a significant enough boost. As of June 4, about 56 percent of adults in Virginia are fully vaccinated, and about 45 percent of the total state population. Dr. Avula said the state appears on track to reach President Biden’s July 4 goal.

While he doesn’t expect Virginia’s vaccination rate to suddenly jump — “we’re in a stage where people with intrinsic motivation have already gotten it” — he hopes it will remain steady.

Rather than prioritize an incentive program, the state’s current strategy is to make vaccines more accessible. That means using mobile vaccination unites to bring shots to more rural areas and spots with foot traffic, for example, and setting up clinics at truck stops.

“What we’re recognizing in the remaining (unvaccinated) population is absolutely there are people who are choosing not to be vaccinated, but there’s actually a large number of people who wouldn’t mind, but it wasn’t a big enough priority” to register or go to a vaccination site, Dr. Avula said. “When these potential barriers are lowered, then it makes it a much easier decision.”

Local health districts already have experimented with smaller-scale incentives.

In Norfolk, officials offered free Tides baseball tickets to those who got vaccinated at the stadium on opening night. The Peninsula and Hampton districts have distributed coupon books.

(In Richmond, the city is offering to pay for lunch for anyone who gets vaccinated at a walk-up event 10 a.m. to 4 p.m. Saturday, June 12, at Southside Plaza. All three approved vaccines — Moderna, Pfizer and the single-shot Johnson & Johnson — will be available at the event, which also will feature children’s activities and a job fair.)

As the summer arrives, Dr. Avula believes there will be a role for incentives. But the state has to weigh the costs and benefits.

There are certain people for whom such rewards have the opposite of the intended effect. If someone is already suspicious of the vaccine, government incentives can come off as a bribe and further entrench their views, Dr. Avula noted.

“There is this nuanced threading the needle to figure out how to offer the right incentive in the right populations to yield the benefit,” he said.

Subtle messaging around incentives – and more generally about the vaccine – are hugely important in the rollout, said Dr. Gretchen Chapman, a professor of social and decision sciences at Carnegie Mellon University in Pittsburgh.

Dr. Chapman did research in fall of last year that tested different messages sent to people the night before a scheduled doctor’s appointment.

One message was the standard office reminder, a second noted that flu shots would be available and a third said that a flu shot had been “reserved for you.”

The idea was to trigger what behavioral psychologists call “loss aversion,” Dr. Chapman said, in which people have a tendency not to want to lose something they already own. The message also might prompt people not to want to be rude when “my doctor already went to the trouble of reserving it just for me,” she said.

That theory appeared to work. Those who had gotten a message about a reserved shot were more likely to say they’d get it, albeit not to a huge degree.

The same was found in a mega-study of text message nudges encouraging patients to get vaccinated at their pharmacy. In that study, 22 different “nudge” messages were sent to Walmart pharmacy patients in the fall of 2020 encouraging them to get a flu vaccine.

The most effective? “A flu shot is waiting for you at Walmart.”

The authors wrote that they hope such “carefully crafted messages” could prod people for COVID-19 vaccines as well. As for incentive programs, Dr. Chapman said they often carry messages implicitly.

For some, such a prize may read as, “It’s a risky vaccine and there’s no way you would get it unless I pay you money,” she said. To others, it may be a message of understanding, acknowledging that you may feel a bit sick after a shot, so here’s something as a thank you.

It could also serve as a way to justify getting the vaccine for those whose social circles frown on it. You can say, “Hey, I wanted the cash,” Dr. Chapman said.

There’s research that shows incentives work in some cases to increase vaccinations, including with college students paid to get them and mothers in an Indian village who received dishes in exchange, Dr. Chapman said.

Experts still debate whether incentive models are effective, though, she said. And there are costs built in to offering something like a lottery drawing.

But simply changing the wording of a public health message to encourage vaccinations — along the lines of Dr. Chapman’s research — is free.

Some current vaccine incentive programs:

• United Airlines is offering the chance to win a year of free flights to MileagePlus customers who upload their vaccination card.

• CVS Health recently rolled out a large vaccine sweepstakes with prizes including Super Bowl tickets, a seven-day cruise through Norwegian Cruise Line, a free trip through the Bermuda Tourism Authority, $5,000 giveaways and more.

• Krispy Kreme offers a free doughnut a day to anyone with a vaccination card, through the end of 2021.

• Lyft and Uber offer free rides to anyone needing to get a shot.

• Major League Baseball teams will offer free tickets to those who get vaccinated on site at games.

• Kroger has a “community immunity” pro- gram to give $1 million to a vaccinated person every week in June, and give dozens of vaccinated Americans free groceries for a year.

A list of many other rewards, as well as information about free child care, is available at www.vaccines.gov/incentives.html.