This. Is. FASCINATING: “The vaccine, which contains dead versions of the bacterium Paenibacillus larvae, comes in the form of food. The vaccine is incorporated into royal jelly, a sugar feed given to queen bees. Once they ingest it, the vaccine is then deposited in their ovaries, giving developing larvae immunity as they hatch.” https://www.nytimes.com/2023/01/07/science/honeybee-vaccine.html?smid=nytcore-ios-share&referringSource=articleShare
U.S.D.A. Approves First Vaccine for Honeybees

Dalan Animal Health’s vaccine for American foulbrood, an aggressive bacterial disease, is the first for any insect in the United States.

The New York Times
@lussenpop This may be a game changer, especially in southern climes where they have no brood break and the queens lay year round! Don't know who's old enough to remember the first polio vaccine - a pink dot of liquid dropped onto a sugar cube.