FDA Grants Emergency Use for Moderna
COVID-19 Vaccine

Damian McNamara

December 18, 2020

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As expected, the US Food and Drug Administration granted Moderna an emergency use authorization (EUA) for its messenger RNA COVID-19 vaccine today. The vaccine becomes the second authorized for emergency use in the United States, and will likely increase the number of vaccine doses available in the coming days.

There is one final step — the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices will need to recommend its use, as it did 2 days after the Pfizer/BioNTech mRNA vaccine received its EUA on December 10.

The EUA for the Moderna vaccine is "a major milestone in trying to contain this pandemic," Hana Mohammed El Sahly, MD, told Medscape Medical News.

Dr Hana Mohammed
El Sahly

Scaling up distribution of the two vaccine products will come next. She notes that even under less emergent conditions, making sure people who need a vaccine receive it 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 EUA for the Moderna vaccine follows a review by the independent VRBPAC members on December 17, which voted 20-0 with one abstention to recommend the EUA. The vaccine is authorized for use in people 18 and older.

Dr Stephen Schrantz

Emergency approval of a second COVID-19 vaccine "is great — we need all the tools we can to fight this pandemic," Stephen Schrantz, MD, infectious disease specialist and assistant professor of medicine at the University of Chicago, told Medscape Medical News. "The early data coming from Moderna looks good, and I agree with the FDA that an EUA is indicated.

"It's incumbent upon all us healthcare professionals to put ourselves out there as supporting this vaccine and supporting people getting it," Schrantz continued. "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 3 clinical trials."

Dr Susan Bailey

"I know the critical role physicians play as vaccine influencers," AMA President Susan Bailey, MD, said during a December 14 webinar for journalists reporting on COVID-19 vaccines. "We have to continue to do what physicians have always done: review the evidence and trust the science. Lives are at stake." The webinar was cosponsored by the AMA and the Poynter Institute.

Ramping Up Healthcare 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 healthcare workers and staff, and now we have it," Aneesh Mehta, MD, of Emory University School of Medicine in Atlanta, Georgia, told Medscape Medical News.

"We had been hoping for a vaccine with a 70% or 80% efficacy, and to see two vaccines now with greater than 90% efficacy is remarkable," he added.

The efficacy levels associated with both mRNA 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 at Baylor College of Medicine in Houston, Texas.

Unanswered Questions Remain

Schrantz likewise said the high efficacy rate was important but not all that is needed. "[W]hat 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 in the long run is another question. Answers could come over time from the ongoing phase 3 trials, as well as from post-EUA surveillance among vaccine recipients.  

"Our work is not done after issuing an EUA," FDA Commissioner Stephen Hahn, MD, said in a JAMA webinar on December 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."

Dr Paul Offit

"The key is to be humble, keep your eyes open and know that once the vaccine is out there, there may be things we learn that we don't know now. That is true for virtually any medical innovation," Paul Offit, MD, director of The Vaccine Education Center at Children's Hospital of Philadelphia and a member of the FDA VRBPAC, said during the AMA/Poynter Institute webinar.

Patricia Stinchfield

During the same webinar, an attendee asked about prioritizing immunization for spouses and family members of healthcare workers. "My husband wants to know that too," replied Patricia A. Stinchfield, APRN, CNP, pediatric nurse practitioner in infectious diseases at Children's Minnesota, St. Paul.

"It is true we should be thinking about our healthcare workers' family members. But at this point in time we just don't have the supplies to address it that way," said Stinchfield, who is also the president-elect of the National Foundation for Infectious Diseases.

Advantages Beyond the Numbers?

"The major advantage of having two vaccines is sheer volume," Mehta said. An additional advantage of more than one product is the potential to offer an option when a specific vaccine is contraindicated. "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," Offit 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 does 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 an 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."

Future Outlook

Dr Aneesh Mehta

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 vaccines 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."

"My greatest hope is that a year from now we look back and realize we did something really amazing together," Bailey said, "and we have a feeling of accomplishment and appreciation for all the hard work that has been done."

Mehta shared the important message he shares when walking around the hospital: "While these vaccines are coming and they are very promising, we need to continue to remember the 3 Ws: wearing a mask, washing your hands, and watching your distance," he said.

"With the combination of those 3Ws and those vaccines, we will hopefully come through this COVID pandemic."

El Sahly receives funding through the NIH for her research, including her role as co-chair of the Moderna vaccine phase 3 clinical trial. Schrantz is a site investigator for the Moderna and Janssen vaccine trials. Mehta also receives funding through the NIH. None of these experts had any relevant financial disclosures.

Damian McNamara is a staff journalist based in Miami. He covers a wide range of medical specialties, including infectious diseases, gastroenterology and critical care. Follow Damian on Twitter:  @MedReporter.

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