NIH Raises Concerns About Potential Safety Issues Associated with AstraZeneca Vaccine

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NIH Raises Concerns About Potential Safety Issues Associated with AstraZeneca Vaccine


The National Institutes of Health (NIH) is raising concern about the safety of AstraZeneca’s coronavirus vaccine, even as the U.S. Food and Drug Administration is weighing whether or not to resume testing in the United States following a global pause in the trial for safety reasons.

On Monday, AstraZeneca resumed testing in the United Kingdom after regulators deemed it was safe for the trial to resume there. AstraZeneca paused its Phase III global vaccine  study for safety concerns after a participant in the COVID-19 study was hospitalized with suspicion of having developed a serious spinal inflammatory disorder called transverse myelitis. AstraZeneca confirmed the patient had been dosed with the company’s experimental coronavirus vaccine candidate, AZD1222 and paused the study. It has yet to be determined if the vaccine was connected to the issue or, if she indeed had transverse myelitis, an inflammation of a part of the spinal cord that can lead to pain, muscle weakness, paralysis, sensory problems, or bladder and bowel dysfunction. The patient, who was hospitalized from the complications, has been released.

Dr. Avindra Nath, intramural clinical director and a leader of viral research at the National Institute for Neurological Disorders and Stroke, a division of the NIH, told CNN that the highest levels of people in the NIH are concerned about the potential safety issue with the vaccine.


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“AstraZeneca ‘need[s] to be more forthcoming with a potential complication of a vaccine which will eventually be given to millions of people,’” Nath said to CNN. “We would like to see how we can help, but the lack of information makes it difficult to do so.”

Nath said the NIH is hoping to receive tissue or blood samples from the British patient to make its own determinations. He said the agency’s investigation into the matter is still in the planning stages. In addition to looking at blood and tissue samples from the U.K. patient, Nath said NIH scientists could also look at samples from other patients who received the vaccine to determine is the antibodies that were generated from the medication could also end up attacking the brain or spinal cord tissue.

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The concern there, as CNN reported, is a rare event known as molecular mimicry. In these circumstances, some pieces of the vaccine could be similar to the brain and spinal cord tissue. Those pieces could trigger an immune response to attack the brain and tissue of the spine, resulting in a disorder like transverse myelitis. If that turns out to be the cause of the patient’s issue, and it happens again, it could potentially shut down the trial, William Schaffner, an infectious disease specialist at the Vanderbilt University School of Medicine, told CNN. That happened in a 1976 vaccination study for swine flu. It was determined that the vaccine for that flu led to rare instances of patients becoming more susceptible to developing Guillain-Barré syndrome, a condition in which the immune system attacks the nerves. It can be caused by bacterial or viral infection.

The FDA has not indicated when it will allow the AstraZeneca trial to resume here. The regulatory agency will have to review the data collected by the Independent Data and Safety Monitoring Board overseeing the U.K. trial and make its determinations from there. The FDA did not indicate any timeline for resuming the trial in the U.S., which was only launched last month.

In its brief announcement Saturday, AstraZeneca and its development partner the University of Oxford, said they could not disclose any additional medical information at the time. All trial investigators and participants will be updated with the relevant information and this will be disclosed on global clinical registries, according to the clinical trial and regulatory standards, the company said. AstraZeneca said it will expedite the review of the patient’s illness to minimize any potential impact on the timeline of the trial. If the vaccine makes it through regulatory trials, AstraZeneca plans to manufacture two billion doses of its vaccine, with 400 million slated for the U.S. and UK, and one billion allotted for low- and middle-income countries.


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