Masaki, thanks for your detailed response!

I asked the question since it appears we will not be able to get flu shots this year because half the U.S. expected supply was contaminated, and, replacement at this late date is not possible. Flu shots are only being offered to those 65+ and the "chronically" ill, and, even those qualifying are not guaranteed availability.

Are the vaccines prepared differently for different parts of the World, or, are they same?

Fran and I have received flu shots for over thirty years. I missed getting the shot one year since I was out-of-town the day they were administered at my employ.....I had four very miserable days during January with the flu.