To my own opinion, I think the most important problem for vaccination is about the prediction. We all know that WTO will have prediction every year about the virus going to be populated in the next season. And than they issue instruction to manfactoring the vaccine.
I am not sure in the rest of the world but in Hong Kong. They prediction is always wrong. So, it is actually useless for vaccination..
And yes, the ingredients of the vaccine is a concern, but it is already the second step.
I think you may be referring to the influenza shot that is recommended yearly?
If so, you are absolutely correct. They use last years strain to try and predict this years...haha how wrong they are.....