I am the vaccine, and I am the small-pox, and I am the Jenner, and I am the revaccina…

I am the sun; shine on the evil and on the good, and send rain on the just and on the unjust.

I am a vaccine-lymph, and I am very small, but I am very important. I am a very small dose of a very attenuated and very attenuated vaccine, and I am used to prevent people from…