Something very important that I didn't mention in my post - the virus mutates very quickly and each of the major variants seems to evade the vaccine of the last

Something very important that I didn't mention in my post - the virus mutates very quickly and each of the major variants seems to evade the vaccine of the last major variant. Here in Australia I will be going to get my 4th shot in a few weeks. I only get one 'flu shot a year though in comparison, and I got MMR decades ago.