Moderna Vaccine Found Safe, Effective Before Key FDA Review
A medical worker draws the Covid-19 vaccine from a vial, in Cardiff, on Dec. 8, 2020. (Photographer: Ben Birchall/PA Wire/Bloomberg)

Moderna Vaccine Found Safe, Effective Before Key FDA Review

Moderna Inc.’s vaccine is safe and effective for preventing Covid-19 in people ages 18 and older, U.S. regulators said, clearing the way for a second shot to quickly gain emergency authorization and add to the country’s sprawling immunization effort.

The Food and Drug Administration’s staff said in a report on Tuesday that the experimental vaccine is 94.1% effective at preventing symptomatic Covid-19, confirming earlier results released by the company.

The report was posted online ahead of a meeting Thursday of agency advisers who will vote whether to recommend authorization before a final FDA decision. The agency doesn’t have to follow the advice of the independent vaccine experts, though it often agrees with its advisory panels. Last week, the FDA authorized a similar vaccine from Pfizer Inc. and BioNTech SE after an advisory panel voted 17-4, with one abstention, to support its authorization.

The FDA got a much deeper look at Moderna’s clinical-trial data than the numbers previously released to the public by the company. The agency found the shot was similarly effective across racial and ethnic groups and those with underlying medical conditions. It was 86.4% effective in people age 65 and over, according to the report, and 95.6% effective in those 18 to 65. The most common systemic side effects were fatigue and headache.

Moderna Vaccine Found Safe, Effective Before Key FDA Review

Both the Moderna and Pfizer products are based on messenger RNA technology that hasn’t been previously used in human vaccines. Because both are two-dose vaccines, people will need to return to their care providers weeks after their initial shot for a booster.

Between Pfizer and Moderna, Operation Warp Speed officials have said 20 million people in the U.S. are expected to get their first shots by year-end.

Rising Cases

Covid-19 cases and hospitalizations are rising across the country, increasing pressure to get the pathogen under control. While health officials are hopeful that the immunization push will begin to slow a pandemic that has killed more than 300,000 Americans, it isn’t yet known what effect the vaccines have on transmission of the disease.

Pfizer and BioNTech’s vaccine was cleared first in the U.K., where there were a few reports of serious reactions that led regulators there to advise against anyone with a history of significant allergies getting the shot. The FDA didn’t take such a step, but told facilities where the vaccine would be administered to have medication on hand to treat possible allergic reactions, including a severe form called anaphylaxis.

Moderna’s vaccine isn’t yet approved in any other countries and hasn’t yet been used on anyone outside of a clinical trial.

The FDA staff’s analysis of Moderna’s trial data found 11 cases of Covid-19 in the group that received the vaccine and 185 in those that got a placebo instead.

There were three cases of Bell’s palsy, or temporary facial paralysis on one side, in patient’s who go the vaccine, compared to one such case in the placebo group. The FDA report concluded that current data is “insufficient to determine a causal relationship.”

The rare adverse event was also seen in Pfizer’s clinical trial, where four people who got that shot experienced Bell’s palsy. Such safety signals will be followed by federal officials to gain a clearer picture of their potential relationship to the vaccine.

In addition, there were two cases of serious facial swelling in vaccine recipients that Moderna determined were related to vaccination. Overall, the number of serious adverse events judged to be related to vaccination was very small.

Hypersensitivity reactions appeared to be somewhat more common in people who got the vaccine, but there were no severe anaphylactic reactions that occurred soon after vaccination.

Moderna shares, which have increased more than sevenfold since the start of the year, fell 3.7% to $149.14 at 10:06 a.m. in New York trading.

Transmission Question

There isn’t enough data to know if Moderna’s shot is effective at preventing people from being infected with the coronavirus and not show symptoms, according to the report. People with asymptomatic Covid-19 can still spread the virus. Pfizer’s vaccine also hasn’t been tested to see whether it can halt transmission.

Moderna said in an addendum to its own report analyzing the clinical trials, which was also posted ahead of the Thursday meeting, that it took nasal swabs of participants before the first dose of vaccine and then again before the second.

Fourteen in the vaccine group and 38 in the placebo group showed evidence of Covid-19 infection before getting their second vaccine dose but showed no symptoms, the company said, “suggesting that some asymptomatic infections start to be prevented after the first dose.”

Peter Marks, the head of the FDA’s office that oversees vaccines, said Monday during an interview with the Journal of the American Medical Association that the National Institutes of Health is discussing a study to examine vaccination’s effect on asymptomatic transmission.

Once the U.S. grants authorization, advisers to the Centers for Disease Control and Prevention must meet, as they did last week on Pfizer’s vaccine, to give Moderna’s shot the green light and provide specific recommendations for use and monitoring. Moderna’s vaccine will be distributed to sites around the country where health-care workers and residents of long-term care facilities, such as nursing homes, are expected to get the earliest doses.

The first doses from Pfizer and BioNTech to become available in the U.S. were sent to more than 600 sites around the country. The shot must be kept extremely cold and requires special freezers to transport, while Moderna’s can be kept in more traditional cold storage.

©2020 Bloomberg L.P.

BQ Install

Bloomberg Quint

Add BloombergQuint App to Home screen.