Thanks to Andréa, who called it a “CIDU that I’m too lazy to look up.”
I gave in and looked it up! Alicia Keys had a song “Girl on Fire”. And the lookup also finds a few parodies, under titles like “This girl is on Pfizer,” that predate this cartoon. Indeed it seems to be a fast-moving meme, with hashtags on Twitter and TikTok.
The list of manufacturers sounds like the choices for Covid vaccine, though I guess they would be similar for Flu. The song parody with available lyrics certainly made it Covid, and it’s tempting to suppose that was Hilburn’s idea at first which then got softened, as it were. (The actual song dates from 2012)