FILE - In this April 26, 2021 file photo, a nursing student administers the Moderna COVID-19 vaccine at a vaccination center at UNLV, in Las Vegas. Thrown off-stride to reach its COVID vaccination goal, the Biden administration is sending A-list officials across the country, devising ads for niche markets and enlisting community organizers to persuade unvaccinated people to get a shot. (AP Photo/John Locher, File)

WASHINGTON — Thrown off-stride to reach its COVID-19 vaccination goal, the Biden administration is sending A-list officials across the country, devising ads for niche markets and enlisting community organizers to persuade unvaccinated people to get a shot.

The strategy has the trappings of a political campaign, complete with data crunching to identify groups that can be won over.

But the message is about public health, not ideology. The focus is a group health officials term the “movable middle” — some 55 million unvaccinated adults seen as persuadable, many of them under 30.

“We’re not just going to do the mass vaccination sites,” said Health and Human Services Secretary Xavier Becerra. “It’s door to door. It’s mobile clinics. We’re doing vaccinations at church, the PTA meeting, the barber shop, the grocery store.”

Officials have seized on a compelling new talking point, courtesy of the coronavirus. The potent delta variant that has ravaged India is spreading here. Now accounting for about 1 in 5 virus samples genetically decoded in the U.S., the more transmissible mutation has gained a foothold in Mountain West and heartland states. Many of those infected are young and unvaccinated.

The White House has lent its top names to the vaccine push.

President Joe Biden visited a mobile vaccination site in Raleigh, North Carolina, on Thursday. Earlier in the day, first lady Jill Biden held the hand of a woman at a drive-thru vaccination site in Kissimmee, Florida.

Doug Emhoff, the husband of Vice President Kamala Harris, has racked up thousands of frequent flyer miles, visiting at least 18 or 19 states by his count.

The administration also has recruited celebrities and athletes, including country music star Brad Paisley and the Tampa Bay Lightning hockey team. It has teamed up with Twitch and Riot Games to reach online gamers and with Panera and Chipotle to offer free food to those getting a shot.

The message, as Surgeon General Vivek Murthy put it: “If you are vaccinated, you are protected. If you are not, the threat of variants is real and growing.”

It’s unclear how well the levers of persuasion are functioning. Vaccination rates have dropped below 1 million a day, and there’s no sign yet of a turnaround. The administration has acknowledged that it will fall short of its goal of having 70 percent of adults vaccinated by July Fourth.

At this point, about 170 million American adults have received at least one vaccine dose, representing roughly two-thirds of those 18 and older. An Associated Press analysis suggests that Biden’s self-imposed goal may not be reached until late July at current rates of vaccination.

Analysts at HHS have developed a rough sketch of those in the movable middle. They tend to be younger, mainly 18-29. Most are not college educated, and political independents predominate. Black and Latino adults are more likely to fall in this category than people of other backgrounds.

While applauding the Biden administration’s efforts to get Americans vaccinated, some public health experts say there are limits to what persuasion can achieve.

The administration has ruled out vaccine passports that could become a ticket to benefits such as international travel.