What do you mean by "immunizing vaccines"? In the first sentence, you say that flu vaccines are not and in the second you admit they are. Maybe you meant that

What do you mean by "immunizing vaccines"? In the first sentence, you say that flu vaccines are not and in the second you admit they are. Maybe you meant that their coverage is not comprehensive. If so, that's what you should say. mRNA flu vaccines have substantial potential advantages in terms of the ability to target a wider spectrum of variants and faster time to manufacture.