It doesn't provide sterilizing immunity. "A vaccine" prior to March 2020 when Merriam Webster changed the definition, was generally accepted as something that not only prevents you from catching a virus, but prevents you from spreading it to others which is the whole point of their utility. No "other" vaccine is 'ok you're just going to have a little hepatitis' and yeah you can still spread it to others. Parallels to birth control: standard vaccines are like hormonal birth control when you can blow your wad inside the woman with virtually no concern for pregnancy. The mRNA vaccine would be like a condom that you still need to pull out, and even then she gets pregnant but then probably experiences spontaneous abortion in the first trimester, with (((rare instances of full term pregnancy)))