December 16, 2020

FDA scientists just finished evaluating Moderna's vaccine. Here's what they found.

Daily Briefing

    FDA on Tuesday released its first scientific evaluation of Moderna's coronavirus vaccine candidate and confirmed the inoculation's effectiveness, paving the way for the agency to authorize the vaccine candidate's emergency use in the United States.

    FDA scientists confirm Moderna's vaccine is "highly effective" at preventing Covid-19

    FDA analyzed data submitted by Moderna from its large-scale clinical trial on its coronavirus vaccine candidate. For the trial, researchers randomly assigned 30,000 participants to receive either two shots of the vaccine candidate administered four weeks apart or two saline shots, which served as the placebo in the trial, the Washington Post reports. Neither the researchers nor the participants knew which participants had received the vaccine candidate or the placebo.

    After receiving their shots, the participants went on with their normal lives and were potentially exposed to the novel coronavirus in their communities, the Washington Post reports. The researchers followed up with participants to track how many contracted the novel coronavirus and determine whether fewer cases of Covid-19, the disease caused by the virus, occurred among participants who received the vaccine candidate. The researchers began tracking Covid-19 cases among participants two weeks after a participant received their second shots, which is when a person's immune system would produce a full response against the virus if they had received the vaccine candidate.

    According to FDA, Moderna's data showed that 196 cases of Covid-19 occurred among participants in the trial, with all but 11 of them occurring among the group of participants who received the placebo. The data also showed that there were 30 cases of severe Covid-19 and one death from Covid-19 among trial participants who received the placebo, but none among participants who received the experimental vaccine.

    Overall, FDA scientists found that the data showed Moderna's two-shot vaccine regimen was safe and "highly effective" at preventing Covid-19 among participants of all ages, races, and genders. Specifically, the scientists found that the vaccine candidate was 94.1% effective at preventing Covid-19 in the trial and was particularly effective at preventing severe cases of the disease.

    FDA also noted that data submitted by Moderna suggests the vaccine candidate may prevent both symptomatic and asymptomatic infections from the novel coronavirus. The data showed that 52 participants in the trial tested positive for the virus but had no Covid-19 symptoms before they received a second dose of Moderna's vaccine candidate or a placebo. Most of the participants who tested positive for the virus were in the placebo group, which suggests the vaccine may have protected participants against asymptomatic infections after they received a single dose of the inoculation, the Post reports. However, FDA scientists said there's not enough data to assess whether the vaccine can prevent asymptomatic infections or whether it reduces the coronavirus's transmission. As such, FDA called for further studies on the matter.

    In terms of safety, FDA scientists wrote that their analysis "supported a favorable safety profile, with no specific safety concerns identified that would preclude issuance of an emergency use authorization" (EUA) for Moderna's vaccine candidate. Specifically, the scientists found that most participants who received the vaccine candidate experienced brief and relatively mild side effects, including fatigue, headaches, muscle aches, and pain at the injection site. The scientists also found that 16% of participants who received the vaccine candidate experienced lymph node swelling after receiving their second doses of the inoculation.

    The data also showed that none of the participants who received the vaccine candidate experienced severe allergic reactions, which has become a concern following recent reports of two health care workers with histories of allergic reactions experiencing severe allergic reactions after receiving Pfizer's and BioNTech's vaccine in the United Kingdom.

    FDA's scientists noted that the data reported three cases of Bell's palsy, a temporary facial paralysis, occurred among patients who received Moderna's vaccine candidate and one occurred among a patient in the placebo group. The scientists concluded that the rate of Bell's palsy was similar to that expected in the general population, and there was not enough evidence to determine whether the vaccine candidate had caused the condition. However, the scientists wrote, "a potential contribution of the vaccine to the manifestations of these events of facial palsy cannot be ruled out."

    What do experts think?

    Barry Bloom, a professor of public health at Harvard Unviersity, said the results from Moderna's data are "extraordinarily comparable" to the results from data on Pfizer's and BioNTech's recently authorized coronavirus vaccine.

    "The good news is they both did everything they were supposed to do," he said, though he added that it's possible that Moderna's vaccine candidate it slightly less effective than Pfizer's in people ages 65 and older, based on the data. In addition, Bloom noted that Moderna's candidate was linked to higher rates of reported headaches, soreness at the infection side, and other side effects.

    Bloom also noted that Moderna's vaccine candidate is easier to handle, ship, and store than Pfizer's, because it doesn't require being kept at temperatures as cold as Pfizer's vaccine. As a result, he said, "Moderna is the one that I would take out to rural areas and community health centers and private doctors' offices."

    Rupali Limaye, an associate scientist at Johns Hopkins Bloomberg School of Public Health, in response to FDA's review said, "This is great news, as this now brings us to two products with high levels of efficacy." She added, "We're worried about severe cases [of novel coronavirus infection] that lead to hospitalization, which leads to death. … The fact that [Moderna's vaccine candidate appears] able to prevent any cases of severity—I mean, that's huge."

    What happens next?

    An FDA advisory panel is scheduled to meet Thursday to evaluate the data on Moderna's coronavirus vaccine candidate and determine whether there is enough data to support issuing an EUA for the experimental vaccine's use among people ages 18 and older. The FDA scientists' positive review of Moderna's vaccine suggests the panel may endorse the candidate.

    After the advisory panel makes its recommendation, FDA regulators then will decide whether to issue an EUA for the vaccine candidate. FDA is not required to follow to the committee's recommendations, but the agency usually does. According to the Post, a person with knowledge of the situation said FDA is poised to issue an EUA for the vaccine candidate as early as Friday. If FDA chooses to issue the EUA, the United States could have a total of two coronavirus vaccines authorized for use in the country by the end of this week, the Post reports.

    Experts expect that FDA will issue the EUA for Moderna's coronavirus vaccine candidate in the same way the agency issued its EUA for Pfizer's and BioNTech's vaccine. FDA scientists released a positive assessment of Pfizer's and BioNTech's vaccine last Tuesday, and an FDA advisory panel last Thursday endorsed the vaccine candidate's EUA. FDA then issued its EUA for the vaccine candidate last Friday, and the federal government began shipping out doses of the vaccine over the weekend. By Monday, health care facilities had started administering the first doses of the vaccine to frontline health care workers.

    On Monday, Gen. Gustave Perna—COO of Operation Warp Speed, the federal government's coronavirus vaccine initiative—said the federal government is preparing to distribute nearly six million doses of Moderna's vaccine candidate to 3,285 locations in the first week following the inoculation's EUA. "It will be a very similar cadence that was executed this week with Pfizer, where we're hitting initial sites on Monday, follow on Tuesday and Wednesday," Perna said.

    America's coronavirus epidemic continues to surge

    The vaccine developments come as U.S. officials on Tuesday reported about 201,649 new cases of the novel coronavirus, according to data compiled by the New York Times. As of Wednesday morning, U.S. officials had reported a total of about 16.7 million cases of the virus since America's epidemic began—up from about 16.5 million cases reported as of Tuesday morning.

    According to the Times, the United States' average daily number of newly reported coronavirus cases over the past week was 206,557—which is up by 28% when compared with the average from two weeks ago.

    As of Wednesday morning, data from the Times showed that the rates of newly reported coronavirus cases were "staying high" in Puerto Rico; the U.S. Virgin Islands; Washington, D.C.; and 40 states that have had a daily average of at least 15 newly reported cases per 100,000 people over the past week. Those states are Alabama, Alaska, Arizona, Arkansas, California, Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Mississippi, Missouri, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, and Wisconsin.

    Meanwhile, the Times' data showed that, as of Wednesday morning, the daily average number of newly reported cases over the past seven days was "going down" in nine states that had been seeing comparatively higher rates of coronavirus transmission. Those states are Colorado, Iowa, Michigan, Minnesota, Montana, Nebraska, North Dakota, South Dakota, and Wyoming.

    Hawaii has had comparatively low case rates, but it was seeing those rates "going up" as of Wednesday morning, according to the Times. In Guam, meanwhile, rates of newly reported coronavirus cases were "staying low" as of Wednesday morning, the Times' data showed.

    U.S. hospitalizations for Covid-19 grew to a new high for the 18th consecutive day on Tuesday, according to data from The Atlantic's COVID Tracking Project. The data showed that 112,816 Americans with Covid-19 were hospitalized for treatment on Tuesday, including 21,897 who were receiving care in an ICU and 7,702 who were on a ventilator.

    As the numbers of newly reported coronaviruses cases and Covid-19 hospitalizations continue to surge, the daily reported number of Americans who died from the coronavirus has spiked, as well. On Tuesday, U.S. officials reported about 2,957 new deaths linked to the virus. As of Wednesday morning, U.S. officials had reported a total of about 303,963 U.S. deaths linked to the virus since the country's epidemic began, up from about 301,006 deaths reported as of Tuesday morning.

    (Weiland et al., New York Times, 12/15; Herper et al., STAT News, 12/15; Allassan, Axios, 12/15; Johnson, Washington Post, 12/15; New York Times, 12/16; "The COVID Tracking Project," The Atlantic, accessed 12/16).


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