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  • 意大利研究人员发现,与身体健康的人相比,肥胖人群接种第二剂新冠疫苗产生的抗体,约为健康人群产生抗体的一半。

    英国《卫报》上发表的一份报告中表示,数据表明,“辉瑞-BioNTech”疫苗在肥胖症患者中的功效可能较弱,这项研究是由研究员Aldo Vinot及其同事进行的。

    尽管现在就知道这与疫苗有效性之间的关系还为时过早,但这可能意味着,肥胖者需要额外的加强剂量以确保对新冠病毒具有足够的免疫作用。

    实际上,以前的研究表明,肥胖人群感染新冠病毒的死亡风险增加了近50%,而入院风险增加了一倍,达到113%。

    作者指出,这可能归因于以下事实:肥胖的人经常患有其他基本疾病,例如心脏病或2型糖尿病,这些疾病会增加感染新冠病毒的风险,而且体内过多的脂肪还会影响新陈代谢,例如胰岛素的抵抗能力或有炎症,这使人体难以抵抗感染。

    这种慢性的、低度炎症性疾病也会损害一些免疫反应,包括由B细胞和T细胞释放的那些免疫反应,而这些免疫反应在疫苗接种后导致保护性反应。

    研究人员Aldo Vinot及其同事在为248名医护人员接种了两剂“辉瑞-BioNTech”疫苗后评估了抗体反应。

    接受第二剂疫苗7天后,其中99.5%的人对抗体产生了反应,该反应大于新冠肺炎治愈者所记录的反应。但是,超重和肥胖人群的反应较差。

    研究人员Aldo Vinot及其同事写道,“由于肥胖是新冠肺炎患者发病和死亡的主要危险因素,因此,应该为肥胖人群制定有效的疫苗接种计划。”

    尽管需要进行更多的研究,但这些数据可能对开发新冠疫苗接种策略具有重要意义,特别是对于肥胖人群更具有重要意义。

    如果这些数据得到其他深入研究的证实,则给肥胖者接种额外剂量的疫苗或更高剂量的疫苗,这可能是应该评估以赋予肥胖人群免疫力选项之一。

  • Covid Vaccination: The Need For Speed

    Calls for roping in the private sector grow as India’s Covid vaccination drive-being extended to senior citizens in March-runs way behind target.

    When Dr Dinesh Kapadia decided to register for Covid vaccination in New Delhi, he met with fierce resistance from his wife and two children. The reason: at 72 years of age, they felt, Dr Kapadia was too old to risk the potential side-effects of the vaccine. Unable to convince his family, Dr Kapadia quietly got inoculated. It was only two weeks later that he let his family know.

    “I was absolutely fine. The only strenuous bit was waiting in the crowded vaccination centre. Otherwise, I had no other stress, no post-vaccine symptoms, not even swelling at the site of injection,” says Dr Kapadia. He believes age should not be the decider. “Age is just a number. Whether or not to take the vaccine should be decided on the basis of one’s history of allergies, health condition and state of mind. If the process was better communicated and simpler, more people would come forward.”

    As India gears up to start vaccinating those above 50 against Covid from early March-11 million health and frontline workers have taken the shot in the first two phases-fear and confusion dog people. The apprehension isn’t only about the side-effects of the vaccine but the process of taking it. For instance, Asha Singh, a 75-year-old retired banker living in Bengaluru’s Koramangala, says she has received at least 12 social media forwards about how to register for the vaccine-all of them misleading.

    Singh even received a call to submit her details for registration and only midway through it did she realise that it was spam. She complains that CoWin, the government’s official vaccine registration portal, does not work on her iPhone. “First, I had to understand whether it was safe to take the vaccine, then had to figure out if I could decide which of the two vaccines (Covishield or Covaxin) to take. And now, I am struggling with the registration,” she says. Singh adds that she is prepared to be inoculated, but if it gets overly confusing, she would prefer to keep Covid at

    bay through social distancing. “There is so much fake information going around and nothing reliable to counter it, except a phone message that says the vaccines are safe. Trust is in the details.”

    Even though the CoWin app has been integrated into the Aarogya Setu app, registration for the next phase has not been opened and the information provided is basic. While the government’s expert committee on vaccines has been considering walk-in registrations, fake or duplicate data remains a big concern. A member on the expert committee says Census 2011 data would include the names of deceased, so it would be reliable to vaccinate people on the basis of identity proof.

    Meanwhile, in Delhi, 55-year-old Poonam Khanna, a diabetic, has a different dilemma. She is unaware of the potential side-effects of the vaccine and what those with pre-existing health conditions like hers can expect. Handling such information gaps will be the key to ensuring that enough people join the third phase of the Covid vaccination programme. The first two phases have still not seen all those who had registered turn up for their jab, indicating that while there was interest in the vaccine, numbers were being lost when it was time to actually take the shot. “Many of my patients are constantly enquiring about when the vaccine will be available for them. Some have doubts, but these can be addressed by providing facts and figures,” says Dr Naresh Trehan, chairman, Medanta Hospital, Gurugram.

    GO PRIVATE?

    As logistical preparations for the March phase kick off, many experts believe that roping in the private sector would be the most effective way to remove loopholes in vaccine registration, cold chain storage, distribution and public outreach. “Through the pandemic, we saw how people flocked to the private health sector [for treatment]. I shudder to think how the country would have handled the pandemic without their help,” says Dr Sandeep Budhiraja, medical director, Max Healthcare, Delhi, adding that faith in the country’s public health service network remains low.

    Indeed, in the first two phases of the vaccination, the government had targeted 10 million healthcare and 20 million frontline workers. It took 34 days to immunise 10 million people. The private sector is confident of doing this job much faster. According to Wipro founder Azim Premji, the private sector has the capability to vaccinate 500 million people in two months at a cost of Rs 400 per shot.

    In early February, the Pune-based Serum Institute of India, which manufactures Covishield, had a stockpile of 55 million doses. Serum Institute says it can produce an additional 100 million doses per month. Many argue that these surplus doses could have been easily distributed through private providers. “The private sector caters to nearly 70 per cent of the population. It has been involved in most vaccination drives, such as against polio, so why not against Covid?” asks Dr Ravi Wankhedkar, national president of the Indian Medical Association (IMA), which has expressed interest in helping the government with the vaccination drive.

    But chances of the government ceding control over procurement and distribution of the vaccines remain low. ‘Cost’, perhaps, is one of the factors. “Do you forget what happened during the pandemic? Covid patients were getting bills of Rs 11-15 lakh in private hospitals, and some had even charged more than the capped price of Covid tests and included transport and PPE costs in the final bill,” says an official in the Union ministry of health and family welfare (MoHFW), on condition of anonymity.

    Other concerns for the government include the risk of counterfeit vaccines and faulty administering of the shots. “The black market for remdesivir and other Covid drugs grew overnight. We don’t want the same happening to the vaccines,” says the MoHFW official. “Tomorrow, a small clinic could start administering the vaccines and not have trained staff or facilities to monitor recipients for potential side-effects. At such a critical juncture of the pandemic curve, we cannot risk people being vaccinated improperly.”

    While details of the next vaccination phase are sketchy at the moment, it has been announced that private hospitals will be hosting vaccination clinics. It is most likely that people will have the option of choosing from among the available centres. It would also be known whether a centre is administering Covishield or Covaxin, thereby allowing recipients to pick the vaccine candidate of their choice.

    The private sector has had a deep engagement in government health programmes. For instance, some 11,000 private hospitals are empanelled under the Centre’s Ayushman Bharat initiative. Over 800 private hospitals are part of the Central Government Health Scheme (CGHS).

    The services of around 10,000 hospitals are being used in the ongoing phase of the Covid vaccination, of which 2,000 are private. “The Centre recognises the private sector’s force-multiplier role and has been using it. Over the next few days, private hospitals will be used in large numbers to step up the pace and coverage of the vaccination drive,” says Rajesh Bhushan, health secretary.

    Delhi, for example, plans to scale up the number of centres to 300 by the beginning of March. Many of them will be at prominent private hospitals, such as Apollo, Max and Fortis. The national capital currently has 261 centres, of which 228 administer Covishield and the rest stock Covaxin.

    ASSURANCE OF SAFETY

    With states like Maharashtra and Kerala again recording a spike in cases, vaccination is perhaps the best way to contain Covid. A vaccinated person faces a lower risk of suffering a severe bout of Covid. Covishield and Covaxin are the two vaccines being used in India. They are both under emergency use at present, which is why the first two vaccination phases were not open to the general public. Trial data for Covaxin is not available. In the case of Covishield, AstraZeneca has peer reviewed and made public its data from the Europe and Brazil trials. Data from the supplementary trial in India is not yet available in the public domain. The period of immunity and effectiveness against the new Covid strains is also unclear.

    So far, no deaths have been attributed to the two vaccines in India, and ‘adverse’ events, such as a life-threatening allergic reaction, after immunisation have been under 0.5 per cent. An online study of 5,396 healthcare workers (947 of whom were above the age of 60) by the IMA’s Kochi wing suggests that the chances of post-vaccine side-effects decline with age. About 80 per cent of the recipients said they were absolutely fine by the next day; 66 per cent reported at least one side-effect, most commonly tiredness followed by fever, headache or pain at the site of injection. WHO recommends Covishield for people above 65.

    According to MoHFW, the first two phases of vaccination were satisfactory in terms of efficacy and safety, and both Covishield and Covaxin have been tested enough before being offered to the public. “New vaccines are also being developed and should be available soon. The current two vaccines have helped improve immunity against Covid significantly,” says Dr V.K. Paul, member, NITI Aayog, and chairman of the national expert group on vaccine administration for Covid-19.

    Even if Covishield hasn’t been able to prevent mild or moderate symptoms of the South African variant of Covid, it has helped avert serious illness and death. “Any drug or vaccine can cause an allergic reaction. But so far, the Covid vaccines have recorded a very low number of serious adverse reactions,” says Dr Randeep Guleria, director, AIIMS, New Delhi. “Even those with comorbid conditions can take the vaccine. In fact, those who are most at risk should come forward and take it. But it is best to consult your physician before registering for the vaccination.”

  • 专家介绍抗击新冠病毒的有害基因和有益基因

    在感染新冠病毒后,从人类遥远祖先那里继承来的基因可能会提高一个人呼吸衰竭甚至死亡的几率。这是学者们去年年底发表的轰动性声明。专家们急于驳斥这项使人害怕的声明。

    但日本冲绳科学技术大学院大学(OIST)专家们的新研究恰恰证实了相反的事情:尼安德特人(Homo neanderthalensis)的基因可能降低新冠病毒的严重流动风险。

    日本冲绳科学技术大学院大学(OIST)和德国马克斯·普朗克进化人类学研究所(Max-Planck-Institut für evolutionäre Anthropologie )的研究人员发现,现代人正是从尼安德特人那里继承了第12号染色体上的一个部分,而该部分把人在感染新冠病毒时必须开展强化治疗的风险降低了大约20%左右。

    “当然,存在影响疾病的其他因素,比如年老体弱,或罹患糖尿病等慢性病”,日本冲绳科学技术大学院大学人类进化基因组学部门负责人斯万特·帕博(Svante Pääbo) 教授在研究中指出。“但基因因素也扮演着重要角色, 其中一些基因是尼安德特人传递给现代人的。”

    研究中还提到,去年,斯万特·帕博教授与同行雨果·泽伯格(Hugo Zeberg) 在《自然》(Nature)杂志上写道,使一个人在感染新冠病毒后发展成重症增加一倍的风险遗传自尼安德特人。

    现在专家们在新的研究中附有条件——免疫系统明显既会对人产生正面影响,还会对人产生负面影响。

    德国哥廷根大学(University of Göttingen)教授、美国德克萨斯AM大学教授、俄罗斯西伯利亚联邦大学教授、俄罗斯科学院瓦维洛夫普通遗传学研究所主要科研人员康斯坦丁· 克鲁托夫斯基向卫星通讯社评论上述研究时说:“上述工作是重要的,有助于理解先天稳定性的基因控制或对感染新冠病毒的敏感性,哪些单倍体型、基因、等位基因决定这种稳定性。未来在制造治病药物和更好理解个体患病素因时都有所助益。这对制定必要的预防措施来说非常重要。”

    克鲁托夫斯基指出,按照不同的估计,现代人大约有2%到3%的基因是从尼安德特人那里继承的。

    他说:“除了男性性染色体基因外,人的每个基因都有两个‘复制本’——其中一个从母亲那里获得,另一个从父亲那里获得。易变基因可能多于这种基因在种群中的一个变异。这些变异中的一些是在尼安德特人身上出现的,并从与尼安德特人交配的遥远祖先那里遗传给了我们。在某些基因上,一个人可能拥有尼安德特人的两个变异基因——通常同一个人很少有这样的基因——更经常的情况是只存在尼安德特人的一个变异基因,可能从母亲那里获得,可能从父亲那里获得。这些变异基因可能具有不同的效果,甚至是相反的效果。”

    但无法加强有助抗疫的“有益”基因的表现力,也无法削弱“有害”基因的表现力。

    克鲁托夫斯基教授解释说:“目前不存在有助于有目的地加强或削弱同一个基因中的两个变异中的一个变异的表现力。在人类身上开展这种试验是遭到禁止的,在大多国家中,禁止在胚胎上开展此类试验,甚至禁止在人类干细胞上开展此类试验。”

    史前人类基因组研究结果表明,在过去1万年来,种群中“有害”基因的扩散频率固定在10%到13%的水平上,而“有益”基因的扩散频率则在不断上升(在过去1000年来从23%上升到30%)。专家注意到各种因素对基因变异频率的影响。比如,自然选择不会“区分”提高或降低存在病毒的种群的抗病毒稳定性的基因变异的影响。相反,强病毒负荷的存在提高了“有益”变异携带者的生存几率,提高了“有益”变异在后代中出现的频率。

  • 世界需要猴子来开发新冠疫苗,它们的DNA与人类非常相似。但是,由于大流行引起的意外需求导致全球供应的短缺

    世界需要猴子来开发新冠疫苗,它们的DNA与人类非常相似。但是,由于大流行引起的意外需求导致全球供应的短缺

    在新奥尔良郊外的杜兰大学国家灵长类动物研究中心,兽医科技装置每天早上向5000多只猴子分发食物。

    马克·刘易斯(Mark Lewis)急着寻找猴子。这关系到全世界数百万人的生命。
    Bioqual的首席执行官刘易斯负责为莫德纳(Moderna)和强生(Johnson&Johnson)等制药公司提供实验室猴子,这些药企需要它们来研发新冠疫苗。但是,去年新冠病毒席卷美国,在世界各地都很难弄到这种特殊培育的猴子。
    由于无法向科学家提供每只售价都超过1万美元的猴子,大约有十几家公司在疫情最严重的时候到处寻找实验室动物。

    世界需要猴子来开发新冠疫苗,它们的DNA与人类非常相似。但是,由于大流行引起的意外需求导致全球供应的短缺。
    最近的供应短缺再次引发了关于在美国建立战略性猴子储备的讨论,这类似于政府保持的石油和谷物储备。

    美国大约有2.2万只实验猴。大部分是杜兰的这种粉脸恒河猴。

    由于新冠病毒的新变种有可能使目前的疫苗无效,科学家争相寻找新的猴子来源。
    在东南亚以及非洲东南部小岛国毛里求斯,美国科学家在私人和政府资助的设施中寻找首选的实验对象储备——恒河猴和食蟹猕猴(也称为长尾猕猴)。

    美国的七个灵长类动物中心拥有多达2.5万只实验猴,其中主要是粉脸的恒河猴。其中约600至800只猴子在大流行开始后被用在新冠病毒研究。
    科学家说,在进行人体实验之前,猴子是研究新冠病毒疫苗的理想标本。灵长类动物和我们的DNA有90%以上的相似之处,它们的相似生物学特性意味着可以用鼻拭子进行测试并进行肺部扫描。科学家说,几乎不可能用其他动物来测试新冠疫苗,尽管地塞米松——用于治疗唐纳德·J·特朗普(Donald J. Trump)总统的类固醇——等药物使用了仓鼠做实验。
    美国曾经依靠印度来供应恒河猴。但是在1978年,在印度媒体报道说猴子在美国被用于军事实验后,印度停止了出口。制药公司寻找替代方案。

    多年来,由于动物权利活动人士的反对,包括美国主要航空公司在内的几家航司也拒绝运输用于医学研究的动物。

    刘易斯说,与此同时,食蟹猴的价格比一年前增加了一倍以上,大大超出1万美元。研究包括阿尔茨海默氏病和艾滋病在内的其他疾病的科学家说,由于该动物被优先用于新冠病毒研究,他们的工作已被延迟。
    短缺导致越来越多的美国科学家呼吁政府确保持续供应这种动物。
    新奥尔良郊外的杜兰国家灵长类动物研究中心(Tulane National Primate Research Center)副主任兼首席兽医官斯基普·鲍姆(Skip Bohm)说,大约10年前,国家灵长类动物研究中心的主管们开始就战略性猴子储备展开讨论。但是由于建立育种计划需要大量的金钱和时间,所以从未建立起储备。
    “我们的想法有点像战略石油储备,我们在一些地方存放着大量的燃料,只有在紧急情况下才会动用,”鲍姆说。
    但是科学家说,随着病毒新变种的发现,疫苗竞赛可能重启,政府需要立即对库存采取行动。
    哈佛医学院(Harvard Medical School)病毒学和疫苗研究中心首席研究员基思·里夫斯(Keith Reeves)表示:“猴子的战略储备正是我们应对新冠病毒所需要的,可我们就是没有。”

    研究人员经常从一只猴子身上收集数百份标本,这些组织可以冷冻数年,并进行长期研究。科学家们表示,他们会充分利用每只动物,但感染新冠的猴子不能回到其他健康动物之间继续生活,最终必须被实施安乐死。

    美国有七个国家灵长类动物研究中心,这些动物在不接受研究的时候,都过着可接触户外、内容丰富的群居生活。这些设施隶属研究型大学,由国家卫生研究院资助。动物权利活动人士长期以来一直指责这些中心存在虐待行为,包括将幼崽与母亲分开。

    专家表示,美国要为没有足够的研究用猴承担一定责任。
    十多年来,国家灵长类动物研究中心的预算要么持平,要么下降。加州国家灵长类动物研究中心(California National Primate Research Center)传染病专家考恩·范隆佩(Koen Van Rompay)说,联邦政府在大约10年前要求该中心扩大其繁殖群,但是没有给它更多的资金,所以它反而缩小了繁殖群的规模。
    “我们在一些情况下采取了避孕措施,”范隆佩说。“所以春天出生的幼崽会更少。”

  • 根据初步数据 英: 接种疫苗可助中断病毒传播。英格兰公共卫生部的初步研究显示,在接种一剂辉瑞—BioNTech疫苗的人群中,感染冠病住院和死亡的人数减少75%以上

    英格兰公共卫生部的初步研究显示,在接种一剂辉瑞—BioNTech疫苗的人群中,感染冠病住院和死亡的人数减少75%以上。

    (爱丁堡综合电)英格兰公共卫生部采集自医务人员的初步数据显示,接种一剂辉瑞和BioNTech SE联合研发的疫苗,就可将感染冠病风险降低70%以上;接种第二剂后,可降低85%。官员称调查结果表明,接种疫苗有助于中断病毒传播。

    英格兰公共卫生部战略应对主管霍普金斯说:“我们的数据显示,接种疫苗不仅减少有症状感染,也减少无症状感染的数量……减少感染是降低传播的关键。” 

    英格兰公共卫生部的初步研究显示,在接种一剂辉瑞—BioNTech疫苗的人群中,感染冠病住院和死亡的人数减少75%以上。官员称,这款疫苗还显示出对B117变异毒株的高度预防效果。

    这个结果应该可以进一步缓解人们对英国决定扩大两剂间隔时间的担忧。英国希望通过扩大两剂间隔,好让更多人接种。

    英格兰公共卫生部的分析显示,80岁以上人群接种一剂辉瑞疫苗对预防有症状感染的有效性为57%,接种三到四周后产生预防作用。初步数据显示,接种第二剂后可将预防有效性提高至85%以上。

    到目前为止,英国约有1750万人接种了第一剂疫苗,约占全国成年人口的三分之一。英国已有超过12万人死于冠病,是欧洲国家中最多的,但住院人数比1月峰值减少了一半以上。

    苏格兰数据:接种疫苗
    住院风险降低80%以上

    另外,苏格兰的数据也显示,接种疫苗将住院风险降低80%以上。在接种第一剂阿斯利康和牛津大学联合研发的疫苗后,到第四周,住院人数减少了94%;而辉瑞疫苗打一剂之后,住院人数减少85%。

    这项研究是由爱丁堡大学于去年12月8日至今年2月15日,针对苏格兰540万人口中的病患数据所进行的。在这期间,21%苏格兰人口已接种约114万剂疫苗。当地65万人接种了辉瑞疫苗,另外49万人则接种了牛津—阿斯利康疫苗。

    研究团队表示,这项研究结果也适用于使用辉瑞疫苗和牛津—阿斯利康疫苗的其他国家。

    这项研究计划的负责人谢赫在一份声明中说:“这些结果令人鼓舞,并给我们充分理由对未来保持乐观。现在我们在全国各地都有证据表明,疫苗接种可预防冠病所致的住院情况。”他补充说:“现在要在全球范围内加速接种第一剂疫苗,以战胜可怕的冠病疫情。”

    英国免疫学会主席阿克巴也说:“尽管疫苗的有效性对不同年龄层有差异,但年长者住院率下滑仍然令人鼓舞。现在要弄清楚的是,一剂疫苗的保护作用究竟能持续多长时间。”