It's always sunny in philadelphia

My guess: Dennis would not get the vaccine. The golden god isn't susceptible to disease, his body would overpower it in an instant. He catches it from mac later in the episode and almost dies, but still refuses to get the vaccine, considering it a fluke.

Dee would be mad at everyone for not getting it, then get only the first dose of the vaccine and catch it from dennis.

Mac wouldn't get it bc jesus. He'd then almost kill himself with ivermectin.

Charlie would believe mac, but not take ivermectin because it might turn him into a horse. He catches it after mac.

Frank would get the vaccine, but lie about it and push wolf cola as a cure to the public, or make bank by investing in funeral home futures or something. He starts a campaign telling old people that god wouldn't want them to get vaccinated. He's the only one that doesn't catch it in the episode.