[Skybird]

https://www.bbc.com/news/health-59639973

Fighting coronavirus is something your immune system has to learn.

One option is to figure it out on the job when you encounter the virus for real. However, there is a risk of getting it wrong and ending up seriously ill.

Vaccines are more like a school - a safer environment to further your immune system's Covid education.

The first dose is the primary school education that nails the fundamentals.

Your second and third doses are comparable to sending your immune system to secondary school and then university to dramatically deepen its understanding. It's not just repeating primary school over and over.

"The immune system is left with a richer knowledge and understanding of the virus," said Prof Jonathan Ball, a virologist from the University of Nottingham.

He said for all the talk of the dastardly tricks of Omicron, a highly-trained immune system is "an incredibly difficult and hostile environment" for the virus and its variants.