In the hardest of years, almost nothing related to Covid-19 has been joyful. But as the giant vaccine rollout in the U.S. is rapidly widening in its fourth month, some inoculation sites have become intense wells of excitement. Visiting these places feels less like waiting in line for airport security and more like waiting for a Disney ride. In fact, in a sign of these odd times, there is a vaccine station at Disneyland, and some people arrive in Mickey ears, says an Anaheim city spokesman…

Many organizers and workers—including legions of volunteers—say they have developed an esprit de corps and sense they are part of history. They are doing everything from shaking maracas to trying out amateur comedy routines to calm nerves and to help get enough of the population vaccinated to beat back the pandemic.

“We are celebrating life,” said Ana Ducoing, a stay-at-home mother and volunteer cheerleader at the South Bay site. “If we can do something to help end this nightmare, that’s why I’m here.”

As Ms. Ducoing cheered, a Whitney Houston song played, its lyrics channeling the national mood: “Yeah, I wanna dance with somebody!” Nearby, people posed for photos with a cardboard cutout of Dr. Anthony Fauci, the nation’s top infectious disease expert.