Muddle - they are all dead vaccines, but more importantly - there have been and still are - some absolutely LOUSY chest infections about this year - we can probably blame the warmer weather and rain for that (the low (rain) clouds keep all the air full of the bacteria circulating back forth and around us wherever we go instead of it being blown away into space) And of course when it's milder and damper, fungal spores and suchlike breed to their hearts content.
It ain't very healthy all in all! I dread having to go to the docs or hospital at this time of year, every year because of all the unhealthy people! I know that sounds nasty, but it's true.
I have to say before flu jabs became more common - muggins was often the only one at work in some of the places I've worked, especially in an air-con one. Why didn't I get it too? Because I'd had the blooming jab, that's why!
So I'd say they do actually work - for MOST people. Caroline is a bit of a one-off - don't tell her that though, don't want her to get big headed!