Covid: Antibodies 'fall rapidly after infection'
Covid：抗體「在感染後迅速下降」
By James Gallagher
Health and science correspondent
詹姆斯·加拉格爾（James Gallagher）
健康與科學記者
Person in facemask
IMAGE COPYRIGHTGETTY IMAGES
口罩的人
圖片版權蓋蒂圖片社
Levels of protective antibodies in people wane "quite rapidly" after coronavirus infection, say researchers.
研究人員說，冠狀病毒感染後，人體內保護性抗體的水平「迅速消失」。
Antibodies are a key part of our immune defences and stop the virus from getting inside the body's cells.
抗體是我們免疫防禦的關鍵部分，可阻止病毒進入人體細胞。
The Imperial College London team found the number of people testing positive for antibodies has fallen by 26% between June and September.
倫敦帝國理工學院的研究小組發現，在6月至9月之間，抗體檢測呈陽性的人數下降了26％。
They say immunity appears to be fading and there is a risk of catching the virus multiple times.
他們說免疫力似乎正在減弱，並且有多次感染病毒的風險。
The news comes as figures from the Office for National Statistics show that the number of Covid-19 deaths in the UK rose by 60% in the week of 16 October.
該消息發布之際，來自(英國)國家統計局的數據顯示，在英國，Covid-19的死亡人數在10月16日那一周增加了60％。
More than 350,000 people in England have taken an antibody test as part of the REACT-2 study so far.
迄今為止，超過350,000的英格蘭人已接受抗體測試，作為REACT-2研究的一部分。
In the first round of testing, at the end of June and the beginning of July, about 60 in 1,000 people had detectable antibodies.
在第一輪測試中，即6月底和7月初，每1000人中約有60人具有可檢測的抗體。
But in the latest set of tests, in September, only 44 per 1,000 people were positive.
但在9月的最新一組測試中，每千人中只有44例呈陽性。
It suggests the number of people with antibodies fell by more than a quarter between summer and autumn.
這表明在夏季和秋季之間，抗體抗體的人數下降了四分之一以上。
"Immunity is waning quite rapidly, we're only three months after our first [round of tests] and we're already showing a 26% decline in antibodies," said Prof Helen Ward, one of the researchers.
研究人員之一的海倫·沃德教授說：「免疫力正在迅速下降，距離我們的第一輪（測試）僅三個月，而且我們已經顯示出抗體下降了26％。
The fall was greater in those over 65, compared with younger age groups, and in those without symptoms compared with those with full-blown Covid-19.」
與年齡較小的年齡組相比，年齡在65歲以上的人的跌幅更大，與功能成熟的Covid-19的人相比，無症狀的人的跌幅更大。
The number of healthcare workers with antibodies remained relatively high, which the researchers suggest may be due to regular exposure to the virus.
具有抗體的醫護人員的數量仍然相對較高，研究人員認為這可能是由於定期暴露於該病毒引起的。
IMAGE COPYRIGHTGETTY IMAGES
image captionY-shaped antibodies stick to the surface of viruses to stop them infecting the body's cells
圖片版權蓋蒂圖片社
圖片說明Y型抗體會粘附在病毒表面，以阻止它們感染人體細胞
Antibodies stick to the surface of the coronavirus to stop it invading our body's cells and attacking the rest of the immune system.
抗體會粘附在冠狀病毒的表面，以阻止其侵入人體細胞並攻擊其餘的免疫系統。
Exactly what the antibody drop means for immunity is still uncertain. There are other parts of the immune system, such as T-cells, which may also play a role, directly killing infected host cells and calling to other immune cells to help out.
確切地說，抗體滴對免疫的含義仍不確定。免疫系統的其他部分，例如T細胞，也可能發揮作用，直接殺死受感染的宿主細胞並呼籲其他免疫細胞提供幫助。
However, the researchers warn antibodies tend to be highly predictive of who is protected.
但是，研究人員警告說，抗體傾向於高度預測誰會受到保護。
Prof Wendy Barclay said: "We can see the antibodies and we can see them declining and we know antibodies on their own are quite protective.
溫迪·巴克萊（Wendy Barclay）教授說：「我們可以看到抗體，而且可以看到它們在下降，我們知道抗體本身具有很好的保護性。
"On the balance of evidence, I would say it would look as if immunity declines away at the same rate as antibodies decline away, and that this is an indication of waning immunity."
「從證據的平衡來看，我認為免疫力的下降速度似乎與抗體的下降速度相同，這表明免疫力正在減弱。」
There are four other human coronaviruses, which we catch multiple times in our lives. They cause common cold symptoms and we can be reinfected every six to 12 months.
人類還有另外四種人類冠狀病毒，我們在生活中多次感染。它們會引起普通的感冒症狀，我們可以每6到12個月重新感染一次。
Many people have mild or asymptomatic coronavirus infections.
許多人患有輕度或無症狀的冠狀病毒感染
Two out of every three people who tested positive for coronavirus in a study published today by the Office for National Statistics experienced none of the main symptoms of coronavirus.
(英國)國家統計局今天發布的一項研究中，每三分之二的人檢測到冠狀病毒呈陽性反應，但沒有發現冠狀病毒的主要症狀。
Separate figures from the ONS today showed that Covid-19 deaths in the UK increased from just under 500 to just over 750 in the week to 16 October, pushing the total number of deaths 6% over the level expected for this time of year.
來自ONS的單獨數據顯示，在截至10月16日的一周中，英國的Covid-19死亡人數從不到500人增加到750餘人，使死亡總數比一年中這個時候的預期水平高出6％。
At the peak in April, 9,500 Covid-19 deaths were registered in a single week.
在四月份的高峰期，一周內有9,500例Covid-19死亡。
There have been very few confirmed cases of people getting Covid twice. However, the researchers warn this may be due to immunity only just starting to fade since the peak infection rates of March and April.
幾乎沒有人證實兩次獲得Covid的確診病例。但是，研究人員警告說，這可能是由於免疫力從三月和四月的最高感染率才開始減弱。
The hope is the second infection will be milder than the first, even if immunity does decline, as the body should have an "immune memory" of the first encounter and know how to fight back.
希望即使免疫力確實下降，第二次感染也將比第一次感染輕，因為身體應該對第一次接觸有「免疫記憶」，並知道如何抵抗。
The researchers say their findings do not scupper hopes of a vaccine, which may prove more effective than a real infection.
研究人員說，他們的發現不會破壞疫苗的希望，這種疫苗可能比真正的感染更有效。
One of the researchers, Prof Graham Cooke, said: "The big picture is after the first wave, the great majority of the country didn't have evidence of protective immunity.
其中一位研究人員格雷厄姆·庫克教授說：「大局是在第一波浪潮過後，該國大部分地區沒有保護性免疫的證據。
"The need for a vaccine is still very large, the data doesn't change that."
「對疫苗的需求仍然很大，數據並沒有改變。」
Professor Paul Elliott, director of the REACT-2 study, said it would be wrong to draw firm conclusions from the study about the impact of a vaccine.
REACT-2研究的負責人Paul Elliott教授說，從研究中得出關於疫苗影響的堅定結論是錯誤的。
He said: "The vaccine response may behave differently to the response to natural infection."
他說：「疫苗反應與自然感染反應可能有所不同。」
But he said it was possible that some people might need follow-up booster doses of any vaccine that became available to top up fading immunity over time.
但是他說，有些人可能需要跟進任何疫苗的後續加強劑量，以隨著時間的推移補充衰落的免疫力。
Commenting on the findings, Prof Jonathan Ball from the University of Nottingham said: "This study confirms suspicions that antibody responses - especially in vulnerable elderly populations - decrease over time."
諾丁漢大學的喬納森·鮑爾（Jonathan Ball）教授對調查結果發表評論說：「這項研究證實了人們的懷疑，即隨著時間的推移，抗體反應-特別是在脆弱的老年人口中的反應會下降。
However, he said it was still important to get a better overall view of "what protective immunity looks like".
但是，他說，更好地了解「保護性免疫是什麼樣子」仍然很重要。
Prof Eleanor Riley, from the University of Edinburgh, said it would be "premature" to assume immunity did not last, but "the data do lend weight to the concern that antibodies induced by natural infection may be short-lived, as is the case for other seasonal coronaviruses."
愛丁堡大學的埃莉諾·萊利教授表示，認為免疫力不能持久還為時過早，但「數據確實使人擔心自然感染誘導的抗體可能會短暫存在。其他季節性冠狀病毒。」