掩蓋是減少COVID-19感染風險的一種方法。 亞歷克斯·布蘭登/蓋蒂圖片社
唐納德·特朗普總統宣布 他的COVID-19測試陽性 is especially concerning because of his age.由於他的年齡而特別令人擔憂。 At 74 years old, Trump is solidly within an age group that's been hit hard during the coronavirus pandemic.特朗普現年XNUMX歲，穩固地處於一個在冠狀病毒大流行期間遭受重創的年齡組中。
People of all ages can get sick from SARS-CoV-2, the virus that causes COVID-19.所有年齡段的人都可以從SARS-CoV-XNUMX（引起COVID-XNUMX的病毒）中生病。 But the severity of the illness tends to worsen the older the patient is.但是這種疾病的嚴重性往往使患者年齡變大。 Through the end of September,到XNUMX月底， 79％的COVID-19死亡 在美國已有65歲以上的患者。這些統計數據是 大致相似 在世界各國.
What is it that puts older people at increased risk from viruses like SARS-CoV-2?是什麼使老年人更容易受到SARS-CoV-XNUMX等病毒的威脅？ Scientists think it's primarily due to changes in the human immune system as we age.科學家認為，這主要是由於人類衰老過程中人體免疫系統的變化。
人體抵抗病毒感染的工具
As you go about your life, your body is constantly bombarded by pathogens – the bacteria, fungi and viruses that can make you sick.在您的生活中，您的身體會不斷受到病原體的襲擊，這些病原體可能使您生病，而細菌，真菌和病毒會給您造成傷害。 A human body is a great place for these organisms to grow and thrive, providing a nice warm environment with plenty of nutrients.人體是這些生物得以生長和繁衍的好地方，提供了一個充滿營養的良好溫暖環境。
That's where your immune system comes in. It's your body's defense system against these kinds of invaders.那就是您的免疫系統進入的地方。這是您的身體針對這些入侵者的防禦系統。 Before you're even born, your body starts producing specialized B-cells and T-cells – types of white blood cells that can recognize pathogens and help block their growth.在您出生之前，您的身體就開始產生專門的B細胞和T細胞-可以識別病原體並幫助阻止其生長的白細胞。
T細胞通過識別感染的細胞並殺死它們來發揮作用。 Together they make up what scientists call your “adaptive” immune system.它們共同構成了科學家所謂的“自適應”免疫系統。
Maybe your physician has checked your white blood cell levels.也許您的醫師檢查了您的白細胞水平。 That's a measurement of whether you have more B-cells and T-cells in your blood than usual, presumably because they're fighting infection.這是對您的血液中B細胞和T細胞是否比平時更多的一種度量，大概是因為它們正在抵抗感染。
When you're very young, you don't have a lot of these B- or T-cells.當您很小的時候，這些B細胞或T細胞就不會很多。 It can be a challenge for your body to control infection because it's simply not used to the job.控制您的身體可能是一個挑戰，因為它根本不習慣工作。 As you mature, your adaptive immune system learns to recognize pathogens and handle these constant invasions, allowing you to fight off infection quickly and effectively.隨著年齡的增長，您的適應性免疫系統將學會識別病原體並處理這些不斷發生的入侵，從而使您能夠快速有效地抵抗感染。
While white blood cells are powerful people-protectors, they're not enough on their own.儘管白細胞是強大的保護人的物質，但單靠它們還不夠。 Luckily, your immune system has another layer, what's called your幸運的是，您的免疫系統還有另外一層，那就是您的 “先天”免疫反應。 Every cell has its own little immune system that allows it to directly respond to pathogens quicker than it takes to mobilize the adaptive response.每個細胞都有自己的小免疫系統，使它對動員病原體的反應比動員適應性反應要快。
The innate immune response is tuned to pounce on types of molecules that are commonly found on bacteria and viruses but not in human cells.調節先天免疫反應，以突觸在細菌和病毒上常見但在人類細胞中不常見的分子類型。 When a cell detects these invader molecules, it triggers production of an antiviral interferon protein.當細胞檢測到這些入侵分子時，就會觸發抗病毒干擾素蛋白的產生。 Interferon triggers the infected cell to die, limiting infection.干擾素觸發受感染的細胞死亡，從而限制了感染。
另一種類型的先天免疫細胞，稱為單核細胞，起著一種細胞跳動的作用，擺脫了它發現的任何感染細胞，並發出了適應性免疫應答轉變為齒輪的信號。
先天性和適應性免疫系統可以一起充當微調的機器，以檢測和清除病原體。
免疫系統較弱
當病原體入侵時，疾病與健康之間的區別是病原體可以在您體內傳播的速度與免疫反應在不引起過多附帶損害的情況下可以反應的速度之間的競賽。
隨著人們年齡的增長，其先天性和適應性免疫反應發生變化，從而改變了這種平衡。
老年人的單核細胞 產生較少的干擾素 in response to viral infections.應對病毒感染。 They have a harder time killing infected cells and signaling the adaptive immune response to get going.他們很難殺死被感染的細胞，並發出適應性免疫反應以繼續前進。
通常在衰老過程中發生的個人低度慢性炎症也可能 減弱先天性和適應性免疫反應的能力 to react to pathogens.對病原體做出反應。 It's similar to becoming used to an annoying sound over time.這類似於隨著時間的流逝習慣於令人討厭的聲音。
As you age, the reduced “attention span” of your innate and adaptive immune responses make it harder for the body to respond to viral infection, giving the virus the upper hand.隨著年齡的增長，先天性和適應性免疫反應的“注意力跨度”降低，使人體對病毒感染的反應更加困難，從而使病毒佔了上風。 Viruses can take advantage of your immune system's slow start and quickly overwhelm you, resulting in serious disease and death.病毒可以利用免疫系統的緩慢啟動並迅速使您不知所措，從而導致嚴重的疾病和死亡。
社會疏遠至關重要
Everyone, no matter their age, needs to protect themselves from infection, not just to keep themselves healthy but also to help protect the most vulnerable.每個人，無論年齡大小，都需要保護自己免受感染，不僅要保持健康，還需要保護最脆弱的人群。 Given the difficulty older individuals have in controlling viral infection, the best option is for these individuals to avoid becoming infected by viruses in the first place.鑑於老年人在控制病毒感染方面存在困難，因此最好的選擇是讓這些人首先避免被病毒感染。
在這裡洗手，避免碰到臉，自我隔離和 社會疏遠 都變得很重要 特別是對於COVID-19.
打噴嚏噴出的薄霧可以將病毒傳播到空中，因此其他人可以將其吸入。 詹姆斯加特尼, CC BY
COVID-19是由呼吸道病毒引起的，它可以通過微小的含病毒飛沫傳播。 Larger droplets fall to the ground quickly;較大的水滴會迅速掉落到地面； very small droplets dry up.非常小的水滴幹dry。 Mid-range droplets are of most concern because they can最關注中程液滴，因為它們可以 漂浮在空中幾英尺 before drying.乾燥前。 These droplets can be inhaled into the lungs.這些液滴可以吸入肺中。
與他人保持至少6英尺的距離有助於顯著減少您被別人傷害的機會 被這些氣溶膠滴感染。 But there's still the但是仍然有 病毒污染表面的可能性 that infected people have touched or coughed on.被感染的人已經感動或咳嗽。 Therefore, the best way to protect vulnerable older and immunocompromised people is to stay away from them until there is no longer a risk.因此，保護易受傷害的老年人和免疫受損的人的最佳方法是遠離他們，直到不再有危險為止。 By stopping the spread of SARS-CoV-2 throughout the whole population, we help protect those who have a harder time fighting infection.通過阻止SARS-CoV-XNUMX在整個人群中的傳播，我們可以幫助保護那些難以抵抗感染的人。
本文借鑒了以下內容 最初發表的文章 3月19，2020。
關於作者
微生物學，免疫學和病理學副教授Brian Geiss， 科羅拉多州立大學
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