US regulators are "very concerned" about the possible side effects of AstraZeneca and Oxford University's coronavirus vaccine and are discussing whether or not to resume studies.
The process was halted last week when a British participant was rushed to hospital after a severe reaction that caused inflammation of the spinal cord.
On Saturday, the drug maker announced that trials for the vaccine would continue in the UK, but the American arm was not restarted.
The halt remains in place while the U.S. Food and Drug Administration (FDA) conducts an independent investigation, as does the National Institutes of Health (NIH).
On Tuesday, FDA Commissioner Stephen Hahn announced to Sen Tim Scott (R-South Carolina) during an Instagram Live event that the trial of AstraZeneca in the US is still ongoing.
US regulators say they are "very concerned" about AstraZeneca and Oxford University's coronavirus vaccine after the study was interrupted because of a UK spinal cord infection. Pictured: A participant is dosed in AstraZeneca's vaccine study
The study has restarted in the UK, but US scientists want to first determine if the vaccination caused the vaccine or if it was due to some other factor, such as an underlying disease, before resuming the US arm. Pictured: AstraZeneca headquarters in 2013
"The highest NIH scores are very concerned," said Dr. Avindra Nath, clinical director of the National Institute for Neurological Disease and Stroke at the NIH, told Kaiser Health News.
"Everyone's hoping for a vaccine, and if you have a major complication it could derail."
It is unclear exactly how the response was, but Nath and other neurologists believe the patient was diagnosed with transverse myelitis, an inflammation of a section of the spinal cord.
It damages the myelin sheath, an insulating barrier made of fatty protein that protects nerves, and disrupts messages sent by spinal cord nerves.
This leads to pain, weakness, abnormal sensations, and problems with the bladder and intestines – and can even lead to permanent paralysis.
Transverse myelitis can be caused by a variety of diseases, including infections such as influenza and immune system disorders.
Around 1,400 cases are diagnosed in the United States each year, according to the National Organization for Rare Disorders.
& # 39; This is a Serious Adverse Event. It resulted in hospitalization, but the reason the study was canceled is because the true cause of transverse myelitis is not exactly known, "said Dr. William Schaffner, professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center in Nashville, told DailyMail.com.
'It is believed to be due to an immune response. Yes, it is theoretically possible that a vaccine could induce this aberrant immune response and cause transverse myelitis. This is exactly the kind of response that would interrupt the attempt and then cause the Data Protection Authority to conduct an investigation.
According to AstraZeneca, the volunteer has recovered and is no longer in the hospital, but has refused to confirm whether he or she had transverse myelitis.
Nath told Kaiser Health News that officials need to be more open about a potential complication of a vaccine that will eventually be given to millions of people.
"We'd love to see how we can help, but the lack of information makes it difficult to do."
The Medicines and Health Products Regulatory Authority, which is responsible for the safety of medicines and medical devices in the UK, has enabled the UK to restart studies.
However, the FDA and NIH are first trying to determine what caused the reaction, e.g. B. whether it is the vaccine, an underlying disease, or some other unknown factor.
Regulators want to test tissue or blood samples from the UK patient and compare them with samples from other volunteers, Kaiser Health News reported.
This will be to see if they made any antibodies from the immunization that are also attacking the brain or spinal cord tissue.
If scientists determine that the vaccine caused the volunteer to develop transverse myelitis, the arm can be permanently stopped.
According to Schaffner, it is unclear whether the experimental vaccine or the placebo caused this side effect. The longer the investigation, the more suspicion arises.
"I would have thought if this patient had received the placebo, this would have been a really short assessment," Well, that's a placebo. Can't have anything to do with the vaccine. Open the study again, "he said.
"But the longer this takes, the longer the suspicion that the patient received the vaccine becomes more obvious, as this is exactly the kind of aberrant immune response that would be a problem for any vaccine, and especially for this one."
If the study is allowed to proceed, the FDA may require AstraZeneca to provide more safety information to participants before they receive a dose of the vaccine.
"There are so many factors involved in these decisions," Nath told Kaiser Health News.
“I'm sure everything is on the table. The last thing you want to do is hurt healthy people. & # 39;
Two other vaccines are in terminal stage in the US, one from Moderna Inc and the other from Pfizer Inc and its German partner BioNTech.
Recently, Pfizer said it should know whether its experimental vaccine is working or not by the end of October.
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