But experts say it makes sense to prepare people now for the possibility that Covid-19 vaccines may be reactogenic.

“I think one of the things we’re going to have to realize is that all of these vaccines are going to be reactogenic…. They’re all going to be associated with reactions,” said Kathryn Edwards, scientific director of the Vanderbilt Vaccine Research Program in Nashville, Tenn.

“I think if you were to point out that, look, this is going to be a little bit painful, but there’s an end to it, and there’s a greater good to be gained here, I think that that’s probably worthwhile,” agreed Brian Southwell, senior director of the science in the public sphere program at the Center for Communication Science at RTI International, a think tank located in Research Triangle Park, N.C.