FILE - In this Aug. 14, 2020, file photo, laboratory technicians work at the mAbxience biopharmaceutical company on an experimental coronavirus vaccine developed by Oxford University and the laboratory AstraZeneca in Garin, Argentina. AstraZeneca announced Monday, Aug. 31, its vaccine candidate has entered the final testing stage in the U.S. (AP Photo/Natacha Pisarenko, File)

FILE - In this Aug. 14, 2020, file photo, laboratory technicians work at the mAbxience biopharmaceutical company on an experimental coronavirus vaccine developed by Oxford University and the laboratory AstraZeneca in Garin, Argentina. AstraZeneca announced Monday, Aug. 31, its vaccine candidate has entered the final testing stage in the U.S. (AP Photo/Natacha Pisarenko, File)

AstraZeneca COVID-19 vaccine study paused after one illness

An AstraZeneca spokesperson confirmed the pause in vaccinations covers studies in the U.S. and other countries

Late-stage studies of AstraZeneca’s COVID-19 vaccine candidate are on temporary hold while the company investigates whether a recipient’s “potentially unexplained” illness is a side effect of the shot.

In a statement issued Tuesday evening, the company said its “standard review process triggered a pause to vaccination to allow review of safety data.”

AstraZeneca didn’t reveal any information about the possible side effect except to call it “a potentially unexplained illness.” The health news site STAT first reported the pause in testing, saying the possible side effect occurred in the United Kingdom.

An AstraZeneca spokesperson confirmed the pause in vaccinations covers studies in the U.S. and other countries. Late last month, AstraZeneca began recruiting 30,000 people in the U.S. for its largest study of the vaccine. It also is testing the vaccine, developed by Oxford University, in thousands of people in Britain, and in smaller studies in Brazil and South Africa.

Two other vaccines are in huge, final-stage tests in the United States, one made by Moderna Inc. and the other by Pfizer and Germany’s BioNTech. Those two vaccines work differently than AstraZeneca’s, and the studies already have recruited about two-thirds of the needed volunteers.

Temporary holds of large medical studies aren’t unusual, and investigating any serious or unexpected reaction is a mandatory part of safety testing. AstraZeneca pointed out that it’s possible the problem could be a coincidence; illnesses of all sorts could arise in studies of thousands of people.

“We are working to expedite the review of the single event to minimize any potential impact on the trial timeline,” the company statement said.

It’s likely the unexplained illness was serious enough to require hospitalization and not a mild side effect such as fever or muscle pain, said Deborah Fuller, a University of Washington researcher who is working on a different COVID-19 vaccine that has not yet started human testing.

“This is not something to be alarmed about,” Fuller said. Instead, it’s reassuring that the company is pausing the study to figure out what’s happening and carefully monitoring the health of study participants.

Dr. Ashish Jha of Brown University said via Twitter that the significance of the interruption was unclear but that he was “still optimistic” that an effective vaccine will be found in the coming months.

“But optimism isn’t evidence,” he wrote. “Let’s let science drive this process.”

Angela Rasmussen, a virologist at Columbia University in New York, tweeted that the illness may be unrelated to the vaccine, “but the important part is that this is why we do trials before rolling out a vaccine to the general public.”

During the third and final stage of testing, researchers look for any signs of possible side effects that may have gone undetected in earlier patient research. Because of their large size, the studies are considered the most important study phase for picking up less common side effects and establishing safety.

The trials also assess effectiveness by tracking who gets sick and who doesn’t between patients getting the vaccine and those receiving a dummy shot.

The development came the same day that AstraZeneca and eight other drugmakers issued an unusual pledge, vowing to uphold the highest ethical and scientific standards in developing their vaccines.

The announcement follows worries that President Donald Trump will pressure the U.S. Food and Drug Administration to approve a vaccine before it’s proven to be safe and effective.

The U.S. has invested billions of dollars in efforts to quickly develop multiple vaccines against COVID-19. But public fears that a vaccine is unsafe or ineffective could be disastrous, derailing the effort to vaccinate millions of Americans.

Representatives for the FDA did not immediately respond to requests for comment Tuesday evening.

AstraZeneca’s U.S.-traded shares fell more than 6% in after-hours trading following reports of the trial being paused.

___

Associated Press writers Matthew Perrone and Carla K. Johnson contributed to this report.

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

Lauran Neergaard, The Associated Press

Coronavirusvaccines

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Rose Sawka, a 91-year old Acropolis Manor resident received her COVID-19 vaccination on Jan. 20, one day after an outbreak was declared at the long-term care facility. Her son Terry Sawka visited with her through the window, like she is seen in an Oct. 2020 photo. (Photo: K-J Millar/The Northern View)
Acropolis Manor COVID-19 cases jump to 20 confirmed

Prince Rupert long term care facility received vaccinations

Illicit drug use has spread in the Northern Health region and overdose emergency calls increased in Prince Rupert by 29.5 per cent from 2019 to 2020. (Photo:THE NEWS/files)
Overdose emergency calls in Prince Rupert spikes by 43.6 % in five years

Northern Health issues illicit drug use warnings

Glenn Hall, resident at Yellowhead Pioneer Residence Assisted Living in Barrierem B.C. received their first COVID-19 vaccinations on Jan. 19. (Pam Simpson photo)
Acropolis residents and staff to receive COVID-19 vaccine

Prince Rupert long term care residents will receive the vaccine on Jan. 20

An outbreak of COVID-19 was declared on Jan. 19 at Acropolis Manor. The long-term care home also had an influenza outbreak nearly two years ago.
COVID-19 outbreak declared at Acropolis Manor

Prince Rupert long-term care home has four resident, three staff cases

Lax Kxeen Elementary School has two different active notices for potential COVID-19 exposure after three adult lab-confirmed cases of the virus were identified in Prince Rupert schools, School District 52 released in a statement on Jan. 18. (Photo K-J Millar/The Northern View)
Three adult COVID-19 cases result in four potential exposures in city schools

Prince Rupert School District 52 calls special open meeting

Maj.-Gen. Dany Fortin, vice-president of logistics and operations at the Public Health Agency of Canada, speaks at a news conference on the COVID-19 pandemic in Ottawa, on Friday, Jan. 15, 2021. THE CANADIAN PRESS/Justin Tang
B.C. records 500 new COVID-19 cases Wednesday, 14 deaths

Outbreak at Surrey Pretrial jail, two more in health care

A woman writes a message on a memorial mural wall by street artist James “Smokey Devil” Hardy during a memorial to remember victims of illicit drug overdose deaths on International Overdose Awareness Day, in the Downtown Eastside of Vancouver, on Monday, August 31, 2020. THE CANADIAN PRESS/Darryl Dyck
B.C. paramedics respond to record-breaking number of overdose calls in 2020

On the front lines, COVID-19 has not only led to more calls, but increased the complexity

Eighteen-year-old Aidan Webber died in a marine accident in 2019. He was a Canadian Junior BMX champion from Nanaimo. (Submitted)
Inadequate safety training a factor in teen BMX star’s workplace death in 2019

Aidan Webber was crushed by a barge at a fish farm near Port Hardy

Southern resident killer whales in B.C. waters. Research shows the population’s females are more negatively influenced by vessel traffic than males. (Photo supplied by Ocean Wise Conservation Association)
Female orcas less likely to feed in presence of vessel traffic: study

Research the southern resident population raises concerns over reproduction capacity

(Black Press Media files)
Transport Canada not budging on enclosed deck rules, despite calls from BC Ferries union

There have been at least 23 cases of the U.K. variant detected in Canada, four of which are in B.C.

The Elk Valley Hospital is adapting to meet the needs of patients in the Elk Valley.
1-in-5 COVID tests coming back positive in and around Fernie, sparking concern

Dr Ron Clark of Elk Valley Hospital said one in five tests was returning positive for COVID-19

Throughout December, RCMP conducted CounterAttack road checks as police worked to keep roads free of impaired drivers. (BLACK PRESS file photo)
‘You can’t make this stuff up’: Stories from the B.C. CounterAttack campaign

Amusing, yes, but a reminder impaired driving affects ability to drive and to make good decisions

(Thesendboys/Instagram)
Video of man doing backflip off Vancouver bridge draws police condemnation

Group says in Instagram story that they ‘don’t do it for the clout’

Inspection of bridge crossing on a B.C. forest service road. (B.C. Forest Practices Board)
B.C. falling behind in maintenance of forest service roads

Auditor finds nearly half of bridges overdue for repair

Most Read