- During a daylong meeting, experts advising the FDA on coronavirus vaccines talked about the approval process, ongoing clinical trials, and public concerns.
- Vaccine makers will be required to monitor clinical trial participants for an average of 2 months after their final dose to measure safety.
- Any approved vaccine will need to show at least 50 percent efficacy.
- Even after the phase 3 trials are concluded, additional clinical trials will be required to determine safety and efficacy in children, pregnant people, and other groups not included in the initial trials.
Members of an
No specific vaccines were reviewed because phase 3 clinical trials are still ongoing.
The FDA expects to reconvene the expert panel in the future when vaccine makers apply for emergency authorization or standard approval.
Here are the key takeaways from this daylong meeting.
Speed is good, but safety comes first
It normally takes years to develop a new vaccine, but the development of COVID-19 vaccines has moved at a breathtaking pace.
This has been aided by advances in technology and a rapid influx of funding from government and industry.
However, some people have been concerned that the process may be moving too quickly. These concerns have been fueled by President Trump’s continued push for an approved coronavirus vaccine before Election Day on Nov. 3.
Marion Gruber, PhD, director of the FDA’s vaccine research office, sought to allay these fears. “Vaccine development can be expedited. However, I want to stress that it cannot — and must not — be rushed,” she said.
In a
Vaccine makers will need to follow participants for an average of 2 months after their final dose. They will also need to see at least 5 severe COVID-19 cases in the group that received the inactive placebo.
The FDA will also require that a vaccine show at least 50 percent efficacy. This means that a person in a phase 3 trial who received the vaccine would have a 50 percent lower risk of symptomatic COVID-19 compared to someone who got the placebo.
These and other guidelines are intended to ensure that companies have enough data about the risks and benefits of a vaccine before submitting an application to the FDA.
Emergency authorization is not the end of trials
There are two regulatory approval routes that a coronavirus vaccine can follow.
The first is
Vaccine makers can apply for emergency authorization as soon as they have enough data showing that a vaccine provides some benefit. This could occur before the phase 3 trials — which include 30,000 or more participants — are finished.
In comments submitted ahead of the meeting, drugmaker Pfizer indicated that if its vaccine receives an EUA, the company would like to be able to provide the vaccine to study participants who had received the placebo.
The phase 3 vaccine trials are “blind,” meaning that participants don’t know if they’re receiving the candidate vaccine or the placebo.
However, during the meeting, Dorian Fink, a deputy director in the FDA’s Division of Vaccines and Related Products Applications, said that the phase 3 trials should continue as long as possible in order to provide additional safety and efficacy data on the vaccines.
“Once a decision is made to unblind an ongoing placebo-controlled trial, that decision cannot be walked back and that controlled follow-up is lost forever,” he said.
The FDA also indicated that it wouldn’t consider emergency use authorization of a vaccine a reason for a company to end the phase 3 trial — the vaccine would remain experimental even after an EUA.
A key reason for keeping the phase 3 trials going as long as possible is that data required for an EUA is less stringent than what’s needed for full review. Also, some adverse events may not show up until larger numbers of people have been vaccinated.
In addition, EUA’s are sometimes revoked when later data is collected, as happened earlier this year with hydroxychloroquine, a drug that was proposed as a treatment for COVID-19 but turned out to offer few benefits.
Additional clinical trials will be needed even after approval
Even if the phase 3 trials are allowed to run fully to the end, additional clinical trials will be needed. Some of these are currently being planned.
This includes phase 3 trials in children and pregnant people, groups that haven’t been included in the ongoing trials.
Without trials involving these groups, scientists wouldn’t know if the vaccines are safe and effective in these populations.
Pfizer announced last week that it would start enrolling children as young as 12 years old in a vaccine trial.
Other studies will look at the link between vaccination coverage — how many people get vaccinated in an area — and rates of COVID-19 in those areas.
Scientists will also continue to monitor the virus for genetic changes to see if any of these mutations reduce the protection offered by an approved vaccine.
And then there’s the ongoing safety monitoring that’s routinely carried out by the FDA and Centers for Disease Control and Prevention (CDC) for all vaccines.
Work needs to be done to build public support of a vaccine
During the meeting, the Reagan-Udal Foundation, a nonprofit established by Congress to assist the FDA, talked about its efforts to counteract public concerns about coronavirus vaccines or the approval process.
Their initial outreach identified several of these, including distrust of the healthcare system, concern about the speed of vaccine development, and distrust of the government.
There were also concerns among certain groups that the vaccine wouldn’t work for their community.
Some people who provided comments to Reagan-Udal questioned whether enough marginalized communities had been included in the vaccine trials.
During the public comment period for the FDA meeting, Claire Hannan, executive director of the Association of Immunization Managers, said transparency and openness about the vaccine approval process is needed.
“Holding open online meetings allows the public to see for themselves how the process works,” she said.
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