(WNCN) – A new poll finds that Americans who have chosen to skip the COVID-19 vaccine are unlikely to ever change their mind.

According to the poll published Tuesday by the analytics and advisory company Gallup, 78% say they are unlikely to reconsider their vaccination plans, including 51% who say they are “not likely at all” to change their mind and get vaccinated.

That leaves 1 in 5 vaccine-reluctant adults open to reconsidering, with 2% saying they are very likely and 19% saying they are somewhat likely to change their mind and get vaccinated — equivalent to 5% of all U.S. adults.

President Joe Biden has set a goal of having 70% of adults in the U.S. with shots in their arms by the Fourth of July.

States are also trying creative approaches to encourage people to get vaccinated, including offering lottery prizes of varying amounts, savings bonds, free amusement park tickets and free hunting and fishing licenses.

In North Carolina, Gov. Roy Cooper said he has had conversations with lawmakers from both parties about a potential vaccine lottery, something other states have tried to boost vaccination rates.

“We’re certainly looking at what other states have done and looking at their numbers to see if it’s worked. I’ve talked with several legislators on both sides of the aisle about the potential of doing that kind of thing here,” Cooper said. “And, I think most everybody is of the opinion that whatever works, whatever gets people vaccinated, we want to try because we know that’s the key to emerging from this pandemic, to turning our economy around.”

Ohio gave away its first $1 million prize after Gov. Mike DeWine announced his state’s Vax-a-Million giveaway earlier this month. Following that announcement, the Associated Press reported the state’s vaccination rate increased by about 33%, though vaccinations are still down compared to earlier this year.

In North Carolina, state officials launched a pilot program this week in four counties to give people who show up for their first dose of the vaccine a $25 cash card. A person who drives them to a vaccination site is also eligible for a cash card.

Gallup’s data suggest the ceiling on vaccination could be about 80% of U.S. adults.

The reasons for not getting vaccinated vary among Americans. According to Gallup, some cite wanting to be sure the vaccine is safe (23%), while others believe they wouldn’t get seriously ill if they contracted the virus (20%).

Some expressed concerns about the timeline for developing the vaccine (16%) or mistrust of vaccines in general (16%).

Of the respondents, 10% said they already have immunity because they’ve had COVID-19, while 10% cite allergies or concern about allergies as the reason they do not plan to get vaccinated.

Nationally, over 51% of eligible people have received at least one shot, while more than 42% have been fully vaccinated.

People are considered fully vaccinated two weeks after receiving their final dose of either the Pfizer or Moderna COVID-19 vaccines or two weeks after a single-dose vaccine like the Johnson & Johnson vaccine, according to the Centers for Disease Control and Prevention.