【財訊快報／劉敏夫】外電報導指出，歐盟監管機構提出警告表示，頻繁注射Covid-19加強針可能會對免疫系統產生不利影響，此法可能不可行。 歐洲藥品管理局(European Medicines Agency)表示，每四個月重複注射加強針最終可能會削弱免疫系統，並使人感到十分疲勞。相反的，該機構認為，各國應該根據流感疫苗戰略制定的藍圖，在加強免疫計畫之間留出更多時間，並將它們與每個半球寒冷季節的開始聯

Several countries have authorized second booster shots of COVID-19 vaccine, but concerns have recently been raised about whether this is a useful approach.

It’s too soon to understand the effectiveness of a fourth vaccine dose, according to the EU's top drug regulator. But some countries have already authorized the shot.