在一名参与者被专家称为“不良事件”后，阿斯利康暂时停止了其晚期全球新冠肺炎疫苗试验
“虽然有报道称一名志愿者患病，但这可能是由于与疫苗有关的问题。牛津大学的发言人今天早上告诉美国广播公司新闻。
在周二晚上自愿暂停的消息传出之前，牛津大学的研究人员创造的这种有希望的候选疫苗已经进行了几轮临床试验。
美国的试验参与者上周才开始注射。
美国广播公司新闻的专家表示，他们欢迎暂停。
约翰·霍普金斯伯曼生物伦理研究所(Johns Hopkins Berman Institute of Bioethics)的创始人、医学博士露丝·法登(Ruth Faden)对美国广播公司(ABC News)表示:“在这个政治时代，疫苗开发的速度面临着巨大的政治压力，这里的常规秩序占了上风，这非常令人放心。”
“这是临床试验应该如何进行的一个例子，”安娜·p·杜宾医学博士说，她是疫苗研究员，也是约翰·霍普斯金彭博公共卫生学院的教授。
杜宾告诉美国广播公司新闻，“通过暂停试验，阿斯利康正在花时间彻底审查这一事件，这样做，确保产品的安全是重中之重。”
西贝科/路透社
2020年8月27日，约翰内斯堡的RHI·山杜卡尼研究中心，疫苗试验志愿者在接受冠状病毒疾病测试并参与该国新冠肺炎疫苗的人类临床试验之前，等待叫到他们的名字。
专家说，在像这样的大型试验中，一些参与者的疾病是偶然发生的。然后必须停止试验，以便进一步调查疫苗是否与任何严重的不良事件有关。
“不良事件是指接种疫苗后发生的任何不良反应，它可能与疫苗有关，也可能无关，”杜宾说。
不良事件可能是从注射部位发红和疼痛到更严重的并发症。对临床试验来说，重要的是看它是否与疫苗有关。
STAT News周三上午报道称，阿斯利康首席执行官帕斯卡尔·索里奥特(Pascal Soriot)告诉投资者，该不良事件涉及一名英国妇女，她在试验中注射了疫苗，其症状与一种罕见的称为横断性脊髓炎的神经疾病一致。
阿斯利康发言人说，部分原因是，“没有最终诊断，在进行更多测试之前也不会有最终诊断。”
这是阿斯利康的审判第二次暂停。7月，审判也因可能的安全问题而暂停，但问题很快得到解决，审判随后不久恢复。
西贝科/路透社
2020年8月27日，约翰内斯堡的RHI·山杜卡尼研究中心，一名卫生工作者在观看一名疫苗试验志愿者参加该国潜在疫苗的人类临床试验。
杜宾说，再次暂停审判进行调查“绝对不是闻所未闻的”。
“需要注意的是，这是疫苗研究中的正常过程。这就是安全审查的工作方式，”她说。
由疫苗研究领域的独立专家组成的数据和安全监督委员会将协助调查。
为了确定这个疑似横贯性脊髓炎的病例是否与阿斯利康疫苗有关，研究人员可能会调查疫苗给药和神经症状发作之间的时间。根据实验室结果，结果可能需要几天或几周的时间。
布莱恩·斯奈德/路透社
马萨诸塞州沃尔瑟姆的阿斯利康工厂的标志。，2020年9月9日。
他们还可以回顾其他试验参与者中类似不良事件的频率，并查看以前使用其他疫苗治疗横断性脊髓炎的报告。
“据报道，疫苗是导致横贯性脊髓炎的原因之一，但它从未得到明确证明，”NYU·兰贡健康中心的神经免疫学家、纽约市贝尔维尤医院的神经病学主任乔纳森·霍华德博士告诉美国广播公司新闻。
横断性脊髓炎是一种脊髓炎症性疾病，由自身免疫过程引起，身体攻击自己的神经系统组织。这种自身免疫过程可能由感染、潜在的自身免疫疾病或未知原因触发。
包括流感、艾滋病毒、疱疹和其他病毒在内的病毒是已知的罪魁祸首。莱姆病和梅毒等细菌感染也与此有关。在某些情况下，横断性脊髓炎与潜在的自身免疫性疾病如多发性硬化或狼疮有关。
“有更多的信息需要对这一不良事件进行审查，”杜宾说。“你必须看一下所有的数据，并根据你试图预防的疾病的风险进行评估。”
在给美国广播公司新闻的一封电子邮件中，医学教授兼阿拉巴马疫苗研究诊所主任保罗·戈普费尔特博士说，这项调查的影响可能对疫苗计划的未来产生严重影响。
“如果发现横向脊髓炎是由疫苗引起的，那肯定是有问题的，”他说。
西贝科/路透社
2020年8月27日，在约翰内斯堡的RHI·山杜卡尼研究中心，一名卫生工作者在参加该国潜在疫苗的人类临床试验之前，与一名疫苗试验志愿者进行了交谈。
目前，阿斯利康试验的延迟似乎不会对其他安全有效的疫苗试验产生任何连锁反应。
莫德纳的一名官员告诉美国广播公司新闻，莫德纳的疫苗是目前在美国进行大规模晚期试验的三种候选疫苗之一，“虽然莫德纳对阿斯利康的试验没有评论，但我们可以确认，我们目前没有意识到对莫德纳COVE研究的任何影响。”
辉瑞官员告诉美国广播公司新闻，他们正在按计划进行，他们将继续监测和评估参与者的安全性，包括由疫苗安全专家组成的独立数据监测委员会(DMC)的评估。
这位官员说:“到目前为止，还没有发现安全信号，DMC最近建议继续按计划进行试验。”
杜宾说，在给更多人接种疫苗之前，彻底调查疫苗的安全性是一种良好的临床实践。
“在这种氛围下，我赞扬(阿斯利康)暂停这项研究，”她说。
美国疾病预防控制中心主任罗伯特·雷德菲尔德周三在研究美国2020年虚拟国家健康研究论坛的一次讨论中说:“当我们开发这些疫苗时，在安全问题上没有捷径可走。”。
“我认为对美国公众来说，我希望他们和全球公众从中吸取的教训是，安全至关重要，”他补充道。“这些疫苗将被开发，它们将被严格评估安全性，如果有安全问题，我们将基本上放慢速度，看看这一点，以确保我们保持安全是所有这些举措的首要目标的氛围。”
Why AstraZeneca pausing its COVID-19 vaccine trial may be good news
AstraZeneca has temporarily put the brakes on its late-stage, global COVID-19 vaccine trial after a participant came down with what experts call an "adverse event."
"Whilst it has been reported that one trial volunteer has become ill, this may be due to an issue related to the vaccine. It also may not," a spokesperson from Oxford University told ABC News this morning.
The promising vaccine candidate created by researchers at Oxford had been marching through rounds of clinical trials before word of the voluntary pause came down Tuesday night.
Trial participants in the U.S had started injections just last week.
Specialists ABC News spoke with said they welcomed the pause.
"It is very reassuring that in this political era, with very significant political pressure on the pace of vaccine development, that the regular order here prevailed," Ruth Faden, M.P.H., Ph.D., founder of the Johns Hopkins Berman Institute of Bioethics, told ABC News.
"This is an example of how the conduct of clinical trials is supposed to work," said Anna P. Durbin, M.D., a vaccine researcher and Professor at John Hopkins Bloomberg School of Public Health.
"In pausing the trial, AstraZeneca is taking the time to thoroughly review the event and in doing so, ensuring the safety of the product is of highest priority," Durbin told ABC News.
Vaccine trial volunteers wait for their names to be called before being tested for the coronavirus disease and taking part in the country's human clinical trial for a COVID-19 vaccine at Wits RHI Shandukani Research Centre in Johannesburg, Aug. 27, 2020.
Experts say that in large trials like this, illnesses occur in some participants by chance. The trial must then be halted to allow for further investigation into whether or not the vaccine is related to any serious adverse event.
"An adverse event is defined as any untoward reaction that occurs following administration of a vaccine, and it may or may not be related to that vaccine," said Durbin.
Adverse events may be anything from redness and soreness at the injection site to more serious complications. What's important to the clinical trial is to see if it has to do with the vaccine.
STAT News reported Wednesday morning that AstraZeneca CEO Pascal Soriot told investors that the adverse event involves a woman in the United Kingdom who was injected with the vaccine as part of the trial, and has symptoms consistent with a rare neurological disease called transverse myelitis.
An AstraZeneca spokesperson said, in part, "There is no final diagnosis and there won’t be one until more test are carried out."
This is the second time that AstraZeneca's trial has been halted. In July, the trial was also paused for possible safety concerns, but the issue was resolved quickly and the trial resumed shortly thereafter.
A health worker looks on as a vaccine trial volunteer arrives to take part in the country's human clinical trial for potential vaccines at the Wits RHI Shandukani Research Centre in Johannesburg, Aug. 27, 2020.
Pausing the trial again for investigation "is absolutely not unheard of," Durbin said.
"It is important to note that this is a normal process in vaccine studies. This is how the safety review is supposed to work," she said.
The Data and Safety Monitoring Board, made up of independent reviewers who are experts in the field of vaccine research, will be helping with the investigation.
To determine whether this case of suspected transverse myelitis is related to the AstraZeneca vaccine, investigators may look into the timing between vaccine administration and the onset of neurologic symptoms. The results may take days or weeks depending on lab results.
A sign marks an AstraZeneca facility in Waltham, Mass., Sept. 9, 2020.
They may also review the frequency of similar adverse events in other trial participants, and look at any previous reports of transverse myelitis with other vaccines.
"Vaccines have been a reported cause of transverse myelitis, but it has never been definitively proven," Jonathan E. Howard, M.D., a neuroimmunologist at NYU Langone Health and chief of neurology at New York City's Bellevue Hospital, told ABC News.
Transverse myelitis is an inflammatory disease of the spinal cord caused by an autoimmune process whereby the body attacks its own nervous system tissue. This autoimmune process may be triggered by infection, underlying autoimmune disease, or unknown causes.
Viruses including the flu, HIV, herpes, and others are known culprits. Bacterial infections such as Lyme disease and syphilis are also associated with it. In some cases, transverse myelitis is associated with underlying autoimmune disorders like multiple sclerosis or lupus.
"There's a lot more information that needs to be reviewed with this adverse event," Durbin said. "You have to look at all the data in total and evaluate that against the risk of the disease you are trying to prevent."
In an email to ABC News, Dr. Paul Goepfert, professor of medicine and director of the Alabama Vaccine Research Clinic, said that the implications of this investigation could be serious for the future of the vaccine program.
"If transverse myelitis is found to be due to the vaccine, it certainly could be problematic," he said.
A health worker talks to a vaccine trial volunteer before he is tested for the coronavirus disease to take part in the country's human clinical trial for potential vaccines at the Wits RHI Shandukani Research Centre in Johannesburg, Aug. 27, 2020.
For now, the delay in the AstraZeneca trial doesn't appear to have any ripple effects in the other trials for a safe and effective vaccine.
An official with Moderna, whose vaccine is one of the three candidates currently in large-scale, late-stage trials in the United States, told ABC News, "While Moderna has no comment on the AstraZeneca trial, we can confirm that we are not aware of any impact on the Moderna COVE study at this time."
Pfizer officials told ABC News they are on schedule and that they continually monitor and evaluate the safety of their participants, including evaluation by an independent data monitoring committee (DMC) made up of vaccine safety experts.
"To date, no safety signal has been identified, and the DMC has recently recommended continuing the trial as planned," the official said.
Durbin said it is good clinical practice to thoroughly investigate the safety of a vaccine before it is given to more people.
"In this atmosphere, I commend [AstraZeneca] for pausing the study," she said.
"There is no shortcuts when it comes to safety when we’re developing these vaccines," CDC Director Robert Redfield said Wednesday during a Research America's 2020 Virtual National Health Research Forum discussion.
"I think for the American public, what I'd like for them to take away from this -- and the global public -- is that safety is paramount," he added. "That these vaccines are going to be developed, and they're going to be evaluated critically for safety, and if there's a safety issue, we're going to basically slow down and take a look at this to make sure that we stay in that climate that safety is the number one objective of all these initiatives."
