Clearly speaking as a pro-vaxer. Good for him.
I like his message and I hope it takes.
I tried to resist the urge to nitpick, but I just can’t. It’s not a “Cure Disease” spell. It’s a “Protection From Disease” spell, which gives him a massive saving throw bonus.
I have actually seen some real world confusion between treating diseases and preventing diseases, with respect to vaccines.
Considering we give pets shots to prevent them from getting rabies and give humans (different) shots after they’ve already been exposed to rabies to keep them from becoming symptomatic, and how rabies is a frequently referenced disease in both movies/tv and news stories, IMHO it’s not very surprising some people get confused about what vaccines aka “shots” actually do.
AFAIK, rabies is the only disease for which a vaccine after exposure can be effective. And this only because it takes upwards of 6 months for the disease to develop. Please correct me if I wrong.
Vaccination after exposure to some other diseases is recommended (at least in some cases) for tetanus, hepatitis A, hepatitis B, anthrax, diphtheria, and measles. See the article Postexposure Prophylaxis for Common Infectious Diseases