World Health Organization officials said AstraZeneca's decision to delay the phase three trial of its experimental Covid-19 vaccine for safety reasons is a reminder that vaccine development is "not always a fast and a straight road."
AstraZeneca's announced Tuesday that it was placing a hold on stage three human trials for its potential vaccine, which it's developing alongside the University of Oxford, after one of the participants showed signs of a potential serious adverse reaction, which was first reported by STAT News. The company told CNBC that the delay was a "routine action" whenever there's an unexplained illness under investigation.
WHO Chief Scientist Dr. Soumya Swaminathan said Thursday that there's no need to be "overly discouraged" by the news, adding that "these things happen."
"There's a protocol for what you do when something happens," Swaminathan said during a news briefing at the organization's Geneva headquarters. "If it's a mild side effect, there are things to be done. If it's major as it was in this case — it was a severe side event — and therefore the trial was halted. And again this is normal procedure. This is good clinical practice because safety is of the upmost, highest priority in any clinical trial."
While the WHO hopes the vaccine's trials will resume soon, it must wait for more information provided by a data and safety monitoring board, which will determine how to proceed with the trials, Swaminathan said.
"I think this is a good ... perhaps a wake-up call or a lesson for everyone to recognize the fact that there are ups and downs in research, there are ups and downs in clinical development and we have to be prepared for those," she said. "We hope that things will be able to move on but again it depends. It depends on a lot, and we have to wait to see the details of what actually happened."
AstraZeneca's vaccine candidate is one of three in late-stage human clinical trials, joining Pfizer and Moderna, which both began their trials in late July. Pascal Soriot, AstraZeneca's chief executive officer, maintained on Thursday, however, that the company should still know whether its vaccine is effective against the coronavirus by the end of this year as long as trials resume soon, Reuters reported.
The WHO has identified more than 160 vaccine candidates under development with nearly 30 in more advanced human trial phases. But as drugmakers race toward a vaccine at a historic speed, questions surrounding their safety have surfaced.
On Thursday, the Kaiser Family Foundation released findings from its latest Health Tracking Poll that found 62% of Americans worry that political pressure from the Trump administration will lead the U.S. Food and Drug Administration to approve a Covid-19 vaccine before it has enough data to determine whether it's safe and effective.
AstraZeneca's Soriot was one of nine company executives developing a Covid-19 vaccine that signed a pledge ensuring the drugmakers won't submit their vaccines for approval until they prove safe and effective in a Phase 3 trial.
When asked about the timing of a vaccine, WHO's Swaminathan said that it typically takes six months at a minimum before researchers begin to see results from late-stage human trials. Since some of the trials began in July, it's "very possible" interim results could appear by the end of the year, though it will take longer for regulatory agencies to examine the results and license the vaccines, she said.
"It could be that we see some results end of the year, it could be early next year, but that's the time frame in which we start seeing the results. There's no way of predicting currently which ones are going to be effective," Swaminathan said.
Dr. Mike Ryan, executive director of the WHO's health emergencies program, added that discovering and approving a Covid-19 vaccine is "not a race between companies (and) it's not a race between countries."
"This is a race against time, it's a race against the virus, it's a race to save lives," he said. "But let's not bet on any horses until we get to the end of this race."
