試題詳解

50. According to the passage, why did people NOT accept the chickenpox vaccine immediately?
(A) They believed that the virus was weak and not highly infectious.
(B) They thought that scientists did not fully know the side effect of the vaccine.
(C) They were unsure about the utility and effectiveness of the vaccine given its expected duration.
(D) They were convinced it was potentially very toxic, particularly for older children.