護理師在衛教季節性流感預防。關於疫苗接種，下列哪項資訊是正確的？
A nurse is teaching a client about the prevention of seasonal influenza. Which of the following information is correct regarding vaccination?
- AHealthy adults do not need the vaccine if they were vaccinated last year健康成人若去年已接種疫苗，則無需接種
- BThe vaccine can cause the flu because it contains live viruses疫苗會引起流感，因為它含有活病毒
- CThe vaccine provides lifelong immunity after two doses接種兩劑後疫苗可提供終身免疫力
- DVaccination is recommended annually due to changes in circulating viral strains✓ 正解由於循環中的病毒株發生變化，建議每年接種疫苗
流感疫苗衛教的核心是澄清『疫苗致病論』與『接種頻率』的迷思。流感病毒具有高變異性（antigenic drift），因此世界衛生組織每年會根據流行的病毒株更新疫苗內容，這也是為何必須每年接種的原因。B 選項錯誤，常見的注射型流感疫苗是去活化病毒，不可能引發流感；C 選項錯誤，疫苗的保護力會隨時間下降，並無法提供終身免疫；A 選項錯誤，即使去年接種過，今年的保護力已不足。護理師應向病人說明接種的目標是降低重症與併發症（如肺炎）的發生率，保護自己也保護家人。
Annual influenza vaccination is recommended because viral strains mutate frequently, requiring updated vaccine compositions. The injectable vaccine contains inactivated viruses and cannot cause the flu. Immunity wanes over time, so previous vaccination does not provide sufficient protection for subsequent seasons.
美國流感疫苗接種率高度依賴藥局與職場環境，推廣力度極大；台灣則以政府公費計畫為主力，民眾對於『抗病毒藥物（克流感）』的認知有時會蓋過『疫苗接種』的預防重要性。