The COVID vaccine was designed to reduce the spread of an infectious disease, seems to fit the definition. Is there a different vaccine you refer to?

It used to mean something that actually gave you immunity to something. Like Polio.

No, it didn't. That's "sterilizing immunity", which is a feature of some but not all vaccines. Flu shots, for example, have never given full immunity to the flu, but they've always been vaccines.

In fact, some forms of the polio vaccine can give you polio. https://www.cdc.gov/vaccines/vpd/polio/hcp/vaccine-derived-p...

Those can give people around you polio while you remain immune.

If you're shedding active virus, you're infected with polio, even if it's an asymptomatic infection.

No, I think it still meant something that reduces the spread infectious diseases. Like the COVID and Flu vaccines, the Polio vaccine does not provide 100% immunity to 100% of recipients.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4974751/

> something that reduces the spread infectious diseases. Like the COVID

That one doesn't do that though.

don't forget the microchips amirite?!