The Biggest Issue Facing the Successful Production of Influenza Vaccines

Multiple Choice

The biggest issue facing the successful production of influenza vaccines is that ________.

A) flu virus populations evolve rapidly
B) flu vaccines can take months to prepare
C) researchers must successfully predict which flu strain(s) will survive from among the existing strains to become the next season's epidemic
D) All of these are serious issues.
E) Generalized vaccines are easy to produce; none of these are serious issues.