The break, first reported by Stat on Tuesday, came on suspicion of a serious adverse reaction in a single person participating in the UK trial. It is not known what health problems the individual has experienced.
A spokesperson for AstraZeneca said the trial has been suspended as a precaution so scientists can determine whether the disease was in fact linked to the vaccine.
“This is a routine action that should occur whenever there is a potentially unexplained disease in any of the trials, while it is under investigation, ensuring that we maintain the integrity of the trials, ”the spokesperson said.
“In large trials, diseases will occur by chance but must be examined independently,” the spokesperson added. “We are working to expedite the review of the single event to minimize any potential impact on the testing schedule. We are committed to ensuring the safety of our participants and the highest standards of conduct in our trials. ”
Other scientists have warned that the break to investigate is exactly how clinical trials are supposed to work.
” It happens. It’s not common, but it does happen, ”Paul Offit, a vaccine expert at Children’s Hospital of Philadelphia, who sits on the FDA’s vaccine advisory committee, told BuzzFeed News. “The vaccine aims to stop SARS-CoV-2. It is not designed to stop everything that happens in life. You want to make sure it was linked to the vaccine, especially if it happened soon after starting the vaccine. “
The vaccine relies on a harmless chimpanzee virus containing the SARS-CoV-2 spike protein gene to trigger an immune response. It’s a new approach that has yet to result in an approved vaccine, but has been tested in experimental vaccines against other viruses, including influenza and Ebola.
Phase 1 and 2 trials of the vaccine, tested in 1,077 patients, showed promising “neutralizing” antibodies in about 90% of participants. About 60% of patients reported mild or moderate side effects, including fever, headache, and muscle pain, all of which resolved in trials. No serious adverse events were reported during the first trials.
The hiatus comes as scientists and the public have expressed growing concern that President Donald Trump is attempting to rush a coronavirus vaccine ahead of the US election.
On Tuesday, nine pharmaceutical executives, including the CEO of AstraZeneca, released a statement committing to “high ethical standards and sound scientific principles” and “not to submit for approval or authorization for use of emergency only after demonstrating safety and efficacy in a phase 3 clinical study. Offit called such a statement on behalf of pharmaceutical executives “unprecedented.”
“The Trump administration is strengthening federal science-based agencies,” Offit said. “People are concerned that the FDA does not care about their interests. So the pharmaceutical companies are mobilizing and saying that we are looking out for your interests. ”
Others have criticized the fact that the American public must rely on drug companies for information about the vaccine, rather than getting clear information from the federal government.
“What worries me is Operation Warp Speed is treating this like any other product with the industry in mind,” Peter Hotez, vaccine researcher at Baylor College of Medicine in Houston, told BuzzFeed News. “Their silence reflects deafness in tone that a COVID-19 vaccine is not the same as a new acne product. “