I was just explaining how the Pfizer vaccine against Covid-19 works to my parents – not that they were vaccine skeptics or some such, my mother was just curious – so I put my teacher hat on and – inspired by yesterday’s picture post by kestrel – I put it to them thusly:
A virus is an envelope that contains the instruction on how to make a said envelope with the same instructions inside. So the body starts producing said envelopes with the instructions over and over again. The vaccine is similar but it is just an envelope containing the instruction on how to make the virus envelope – but without the instructions inside. Thus when the instructions from the vaccine are used up, the production stops, unlike with the virus. In the meantime, the immune system learns from this how to recognize the envelope, and subsequently, when it encounters the real deal, it can destroy it.
Yes, I do occasionally explain things to my elderly parents in an oversimplified fashion as if they were children. Especially sciencey things. They do not seem to mind.