Stanford doctor explains what's next after COVID-19 vaccine trial paused over volunteer's illness

SAN FRANCISCO (KGO) -- There's a possible setback in the race for a coronavirus vaccine.

The Bay Area was set to begin it's phase 3 trials of AstraZeneca's COVID-19 vaccine, but now the entire study is on hold after a trial participant became ill.

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Now the company must stop to investigate whether it was a serious side effect, or completely unrelated to the injection.

ABC7 news reporter, Kate Larsen, has been in close contact with San Francisco's Department of Public Health, which has been preparing for the Bay Area's AstraZeneca trial. DPH heard the news Tuesday afternoon and there is some surprise and disappointment within the department.

Per study protocol, DPH must defer all inquiries to AstraZeneca at this time.

The company sent ABC7 a statement, which says:

"As part of the ongoing randomized, controlled global trials of the Oxford coronavirus vaccine, our standard review process was triggered and we voluntarily paused vaccination to allow review of safety data by an independent committee. This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated, ensuring we maintain the integrity of the trials. In large trials illnesses will happen by chance but must be independently reviewed to check this carefully. We are working to expedite the review of the single event to minimize any potential impact on the trial timeline. We are committed to the safety of our participants and the highest standards of conduct in our trials."

A source says the affected patient is in the UK, where AstraZeneca is based.

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"It is reason to be concerned, but it's not unusual that this would happen, especially with enrolling thousands and thousands of patients," said Dr. Yvonne Maldonado, a Stanford epidemiologist.

Dr. Maldonado is not part of the AstraZeneca trial, but she has conducted clinical vaccine trials all over the world. "The only reason you need to do these trials these ways is because of exactly this reason. It's possible that the safety signal will be determined to be unrelated and they can move forward."

Last month, ABC7 got an inside look at a San Francisco trial site for the AstraZeneca vaccine. The Bay Area trial was already delayed because of training and paperwork reasons. Now it's unclear when the trial will resume.

Dr. Moldonado explained what investigators need to do, saying, "The product sponsor needs to investigate what happened, every single detail about this patient, every single detail that's relevant to what the serious adverse event was, the timing, the location, what was going on with the investigators. All the records need to be checked and double checked. They need to meet with the data safety monitoring board... they will probably need to check with their own governmental regulatory agencies. There's a lot that will need to be done here."

In their statement, AstraZeneca said they are quote "working to expedite the review of the single event to minimize any potential impact on the trial timeline."

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