Kryptonite
Different variants need different jabs? So existing jabs won't work with these new variants? Confused. I always thought if you had a vaccination it would protect you against the thing you've been vaccinated against, like flu, measles, smallpox, rubella, mumps, polio, chickenpox ...
As the virus mutates it can change the way it attacks the body and how the immune system has to then deal with the virus. That's why we sometimes need a new vaccine.
Many, many variants of flu have been identified over the years, some of them extremely dangerous, some much milder. Every year the scientists have to make a best guess about which ones we need to be protected from when they produce the flu vaccine. Same with the Covid vaccine.
Vaccines can't possibly stop us getting a virus, it would have to prevent it from entering the body. All it can do is help our body overcome the virus so that we don't become seriously ill. How ill we get depends on a number of factors - how good our own immune system is, how much of the virus has entered our body, which variant of a virus has entered the body. As I understand it the early variants Alpha and Delta affected deep in the respiratory system, in our lungs, causing very serious illness. Omicron affected higher up the airways so people got coughs and sneezing and cold like symptoms and were not generally as seriously ill. As far as I know the latest Omicron variants BA.4 and BA.5 are still being assessed.