It almost sounds like the setup for a joke: What does the Pfizer-BioNTech vaccine for the coronavirus have in common with Dippin’ Dots?

Except the answer isn’t a punchline: They’re both distributed via a “cold chain.”

Dippin’ Dots, which are a frozen, pelletized ice cream snack often found at sporting events, are made using liquid nitrogen. In order to reach ice cream stands at stadiums or amusement parks, they have to be kept at extremely low temperatures using dry ice — just like the Pfizer vaccines.

Science journalist Maddie Bender wrote about the comparison between Dippin’ Dots and the coronavirus vaccines for Popular Science. To listen to her conversation with “Marketplace” host Kai Ryssdal, use the media player above.