Dec. 18, 2020 -- As expected, the FDA granted Moderna an emergency use authorization for its COVID-19 vaccine, doubling the number of vaccine doses expected to be available in the coming days for distribution nationwide.
There is one final step -- the CDC’s Advisory Committee on Immunization Practices will need to recommend its use, as it did 2 days after the Pfizer vaccine received its EUA on Dec. 10.
Scaling up distribution of the two vaccine products will come next.
"Even under less emergent conditions, sometimes making sure people who need to get a vaccine can be hard. I hope the media attention around this will make more people aware that there are vaccines that might help them,"
said El Sahly, chair of the FDA Vaccines and Related Biological Products Advisory Committee (VRBPAC).
The emergency authorization for the Moderna vaccine follows a review by the independent committee on Thursday, which voted to 20 to 1 with one abstention to recommend the authorization..
Emergency approval of a second COVID-19 vaccine "is great – we need all the tools we can to fight this pandemic. The early data coming from Moderna looks good, and I agree with the FDA that an EUA is indicated," Stephen Schrantz, MD, infectious disease specialist and assistant professor of Medicine at UChicago Medicine, told Medscape.
"It's incumbent upon all us health care professionals to put ourselves out there as supporting this vaccine and supporting people getting it," Schrantz said. "We want to make sure people who are on the fence understand this is a safe vaccine that has been vetted appropriately through the FDA and through phase III clinical trials.
"I know the critical role physicians play as vaccine influencers," American Medical Association President Susan Bailey, MD, said during a Dec. 14 webinar for journalists. "We have to continue to do what physicians have always done. Review the evidence and trust the science. Lives are at stake."
Ramping Up Health Care Provider Immunizations
"I am very excited to see the FDA's positive review of the Moderna vaccine. We have been waiting to have another vaccine we can use for health care workers and staff – and now we have it," Aneesh Mehta, MD, of Emory University School of Medicine in Atlanta, told Medscape.
"We had been hoping for a vaccine with a 70% or 80% efficacy to see, and to see two vaccines now with greater than 90% efficacy is remarkable," he added.
The efficacy levels associated with both the Pfizer and Moderna messenger RNA vaccines "did exceed expectations for sure – this is not what we built the studies around. It was surprising in the good sense of the word," said El Sahly, who is also associate professor of molecular virology and microbiology and a researcher in the Vaccine and Treatment Evaluation Unit at Baylor College of Medicine in Houston.
Unanswered Questions Remain
Schrantz likewise said the high efficacy rate was a positive. "That being said, what we know about this vaccine is it is very effective at preventing disease. We don't have any understanding at this time whether or not these vaccines prevent infection and transmissibility."
Bailey said, "The jury is still out on whether or not you can still transmit the virus after you've had the vaccine. Hopefully not, but we don't really know that for sure."
"It's risky to think that once you get the shot in your arm everything goes back to normal. It doesn't," Bailey added.
Another unknown is the duration of protection following immunization. The Pfizer and Moderna products "have similar constructs, seem to have a reasonable safety profile and excellent short-term efficacy," El Sahly said. She cautioned, however, that long-term efficacy still needs to be determined.
Whether any rare adverse events will emerge is another question. Answers could come over time from the ongoing phase III trials, as well as from monitoring vaccine recipients.
"Our work is not done after issuing an EUA," FDA Commissioner Stephen Hahn, MD, said in a JAMA webinar on Dec. 14. The FDA is closely monitoring for any adverse event rates above the normal background incidence. "We are going to be transparent about it if we are seeing anything that is not at base level."
Advantages Beyond the Numbers?
"The major advantage of having two vaccines is sheer volume," Mehta said. An additional advantage of more product is the potential to offer an option when a specific vaccine is not recommended for specific individuals. "We could offer someone a different vaccine … similar to what we do with the influenza vaccine."
"The more the merrier in terms of having more vaccine products," Schrantz said. Despite differences in shipping, storage, minimum age requirements and dosing intervals, the Pfizer and Moderna vaccines are very similar, he said. "Really the only difference between these two vaccines is the proprietary lipid nanoparticle – the delivery vehicle if you will."
Both vaccines "appear very similar in their capacity to protect against disease, to protect [people in] various racial and ethnic backgrounds, and in their capacity to protect against severe disease," Paul Offit, MD, director of the Vaccine Education Center at Children's Hospital of Philadelphia and member of the FDA advisory committee, said.
In terms of vaccines in the development pipeline, "We don't know but we might start to see a difference with the Johnson & Johnson vaccine or the Janssen vaccine, which are single dose. They might confer some advantages, but we are waiting on the safety and efficacy data," Schrantz said.
As a two-dose vaccine, the AstraZeneca product dose not offer an advantage on the dosing strategy, "but it is easier to transport than the mRNA vaccines," he said. Some concerns with the initial data on the AstraZeneca vaccine will likely need to be addressed before the company applies for EUA, Schrantz added.
"That is an important question," El Sahly said. The ongoing studies should provide more data from participants of all ages and ethnic backgrounds that "will allow us to make a determination as to whether there is any difference between these two vaccines.
She added that the Pfizer and Moderna vaccines seem comparable from the early data. "We'll see if this stands in the long run."
Now that the FDA approved emergency use of two COVID-19 vaccines, "we need each state to quickly implement their plans to get the vaccines into the hands of providers who need to give the vaccines," Mehta said. "We are seeing very effective rollout in multiple regions of the country. And we hope to see that continue as we get more vaccine from manufacturers over the coming months."
"Within a year of identifying the sequence of this virus we have two large clinical vaccine trials that show efficacy," Offit said. "That was an amazing technologic accomplishment, but now comes the hard part. Mass producing this vaccine, getting it out there, making sure everybody who most benefits gets it, is going to be really, really hard."
"But I'm optimistic," Offit said. "If we can do this by next Thanksgiving, we're going to see a dramatic drop in the number of cases, hospitalizations and deaths, and we can get our lives back together again."