The National Institutes of Health has launched an investigation into the case of a patient who suffered spinal cord damage after joining AstraZeneca’s coronavirus vaccine trial.
The international trial was halted last week when the participant’s illness came to light. Oxford University, which is developing the vaccine with AstraZeneca, said over the weekend that British regulators have allowed the trial to resume in the United Kingdom. The US Food and Drug Administration is weighing whether to follow suit.
“The highest levels of NIH are very concerned,” said 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. “Everyone’s hopes are on a vaccine, and if you have a major complication the whole thing could get derailed.”
A great deal of uncertainty remains about what happened to the unnamed patient. AstraZeneca said the trial volunteer recovered from a severe inflammation of the spinal cord and is no longer hospitalized. Nath and another neurologist said they understood that the patient was afflicted with transverse myelitis, though the company has not confirmed this. Transverse myelitis produces symptoms involving inflammation along the spinal cord that can cause pain, muscle weakness and paralysis.
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. “We would like to see how we can help, but the lack of information makes it difficult to do so.”
Britain’s regulatory body, the Medicines and Healthcare Products Regulatory Agency, reviewed the case before deciding to restart the trial at sites in the UK.
Any decision about whether to continue is bound to be complex. It’s difficult to assess the cause of a rare injury that occurs in a clinical trial. Plus, scientists and health officials have to weigh the risk of uncommon side effects against the benefit of a vaccine with the potential to curb a deadly global pandemic.
“So many factors go into these decisions,” Nath said. Still, he added, “the last thing you want to do is hurt healthy people.”
The NIH has yet to obtain tissue or blood samples from the British patient, and its investigation is “in the planning stages,” Nath said.
US scientists could look at samples from other vaccinated patients to see whether any of the antibodies they generated in response to the coronavirus also attack brain or spinal cord tissue. Such studies might take a month or two, he said. The FDA declined to comment on how long it would take before it decides whether to move forward.
Dr. Jesse Goodman, a Georgetown University professor and physician who was chief scientist and lead vaccine regulator at the FDA during the Obama administration, said the agency will review the data and possibly consult with British regulators before allowing resumption of the U.S. study, which had just begun when the injury was reported. Two other coronavirus vaccines are also in late-stage trials in the U.S.
If the FDA allows the AstraZeneca trial to resume, regulators and scientists surely will be on the watch for similar symptoms in other trial participants.
A volunteer in an earlier phase of testing experienced a similar side effect, but investigators discovered she had multiple sclerosis that was unrelated to the vaccination, according to Dr. Elliot Frohman, director of the Multiple Sclerosis & Neuroimmunology Center at the University of Texas.
Neurologists who study illnesses like transverse myelitis say they are rare — occurring at a rate of perhaps 1 in 250,000 people — and strike most often as a result of the body’s immune response to a virus. Less frequently, such episodes have also been linked to vaccines.