How long does protection from COVID-19 vaccines last?
As Taiwan begins its long-awaited ( ) vaccination drive ( ) one year after the beginning of the pandemic, the promise of an added layer of protection against COVID-19 has many wondering: “How long does protection from COVID-19 vaccines last?”
According to the Associated Press, experts don’t know yet because they’re still studying vaccinated people to see when protection might wear off ( ).
How well the vaccines work against emerging ( ) variants ( ) will also determine if, when and how often additional shots might be needed.
“We only have information for as long as the vaccines have been studied,” said Deborah Fuller, a vaccine researcher at the University of Washington. “We have to study the vaccinated population and start to see, at what point do people become vulnerable ( ) again to the virus?”
So far, Pfizer’s ongoing ( ) trial indicates the company’s two-dose vaccine remains highly effective for at least six months, and likely longer. People who got Moderna’s vaccine also still had notable levels of virus-fighting antibodies ( ) six months after the second required shot.
While the current COVID-19 vaccines will likely last for at least about a year, they probably won’t offer lifelong ( ) protection, as with measles ( ) shots, said Dr. Kathleen Neuzil, a vaccine expert at the University of Maryland.
Variants are another reason we might need an additional shot.
So far, the vaccines appear protective against the notable variants that have emerged, though somewhat ( ) less so on the one first detected in South Africa.
If it turns out we need another shot, a single dose could extend protection of the current shots or contain vaccination for one or more variants.
The need for follow-up ( ) shots will also depend partly on the success of the vaccination push globally, and tamping ( ) down transmission ( ) of the virus and emerging variants.
COVID-19疫苗的有效防護期有多久？
繼COVID-19疫情爆發後將近一年多的時間，台灣近日開始陸續施打疫苗。然而，疫苗的效用也讓許多人質疑，打完規定的兩劑後，到底可以撐多久？
根據美聯社所做的調查，因專家仍然在觀察近期接收疫苗的對象進行研究，目前還無法確定疫苗效能確切能維持多久。
再者，多久需要施打一次疫苗也得依據一般疫苗針對不斷出現的變種病毒的效能而論。
美國華盛頓大學的疫苗研究員德柏拉．富勒 (Deborah Fuller)表示「我們目前手上的資訊僅限於廠商研發疫苗時所做的研究。我們仍然需要觀察已接收疫苗族群的各位在什麼時間點開始又會再次被COVID-19感染。」
依照目前情況而論，輝瑞公司正在進行的實驗表示該公司的兩劑疫苗至少在6個月內仍然高度有效，並且有機會撐得更久。研究同時顯示，接收莫德納疫苗的族群在第二劑的6個月後，體內依舊保留著抗疫抗體。
美國馬里蘭大學疫苗專家凱薩琳．紐澤 (Kathleen Neuzil) 表示，雖然目前的疫苗可能撐到一年之久，但他們如同麻疹疫苗，應無法帶給大家終身的保護力。
變種病毒也可能成為我們需要被施打另一劑疫苗的原因。
目前為止，這些疫苗儘管對於南非發現的變種病毒保護作用較差，對於其他主要流行之變種病毒效力似乎不差。
如果未來發現我們需要再接收一劑疫苗，單一劑有機會延長保護力或是能對抗一種或多種變種病毒的效力。
對後續施打疫苗的需求也將取決於全球範圍內推動疫苗接種的成效，以及遏制病毒和新出現的變種病毒之傳播。
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