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Home » PostsHow Do Scientists Know How To Make A Flu Vaccine If Viruses Can Be Different Every Year<span title='2023-01-17 00:00:00 +0000 UTC'>January 17, 2023</span> · 1 min · 12 words · Leona NorrisFact Monster/Information Please® Database, © 2005 Pearson Education, Inc. All rights reserved.
