Want to know how flu cases are tracked and the common types determined? Or how each year's flu vaccine is designed? Ian M. Mackay, Adjunct assistant professor and Katherine Arden, Virologist, The University of Queensland look at the reasons behind this year's big flu season in Australia: theconversation.com/this-ma...
Note that "Some testing suggests this year’s vaccine is well matched to the circulating viruses.
The flu vaccine is not the most effective of vaccines, but it is safe and the only preventive option we have for now. Of those vaccinated, 10-60% become immune to flu virus." and as one of the authors advises in a reply in the comments section "- you may not have had “the Flu” - well done for keeping up the vaccine by the way - but you more than likely have had quite a few different Flu virus infections over that time. Thankfully, because you immune system has been taught the tricks of battling a range of different Flu viruses, it deals with the incursions quickly and effectively.
The immune system is great that way - its being challenged by many thousands of foreign antigens every day, and it has the capacity to learn about them all and be better prepared to react to them the next time it ‘sees’ them. Immune memory is a wonderful thing. As are vaccines.
Just like our normal memory though, immune memory wanes a bit as we age - so keep those shots up each year - memory needs triggering sometimes!"