Medics, I have a question about vaccinations

[Ozgirl75]

I was chatting with some friends about the flu jab last night (thrilling Saturday night convo!) and we realised that none of us knew the answer to this question - why do some vaccines totally prevent you from getting sick and some just let you catch a milder version of the sickness?
So most of us had covid and we were all vaccinated and we were all mildly ill but clearly had covid. But we wondered why we weren’t going down with mild versions of tetanus, measles, hib, whooping cough etc.
I’m sure there’s a simple answer!

Some viruses don't mutate as much as covid/flu/colds etc......... so one vaccine works and fixes the problem.

There’s different vaccine types - inactivated, live-attenuated, messenger RNA, etc.

This website explains it quite well. www.hhs.gov/immunization/basics/types/index.html

Also depends on how contagious the pathogen is, how many people are vaccinated and whether herd immunity has been achieved.
So some of these illnesses people do still get quite frequently because vaccines have not completely eradicated them. But when someone does get infected they are a lot less likely to transmit it to lots of other people.

Not a medic, but some viruses are large and quite stable, so a vaccination allows your immune system to recognise the virus even many years on. The measles virus can’t mutate much without losing its key ability to enter cells, so the protein configurations that your immune system recognises remain pretty much the same.

Other viruses are fast mutating and may be more difficult for the immune system to recognise, because of their specific protein coats, shape, function etc. This makes it much more difficult for the immune system to recognise and respond to them after a vaccination.

So if (for example), I come across someone who has measles, and I’m vaccinated, my body just deals with the germs that I’m exposed to without me knowing a thing that’s going on? I am 100% symptom free?
I do understand that for some illnesses I’m just not likely to ever be exposed to it, but take tetanus for example - I think it’s in the soil? So presumably now and then my body is exposed to it and just fights off any infection without me even knowing what it’s up to?
It’s so clever!