What To Know About Moderna's COVID-19 Vaccine

The company announced preliminary results Monday morning.

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Just one week after Pfizer announced its COVID-19 vaccine was 90% effective, U.S. pharmaceutical company Moderna has said that its vaccine in late-stage trials is 94.5% effective in preventing coronavirus. Happy vaccine month!

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Moderna's trial tested 30,000 subjects; some got the vaccine, others a placebo. Science reports that only five people with the vaccine contracted COVID-19, while 90 people in the placebo group got it, meaning it's nearly 95% effective.

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These results are still preliminary and not from a peer-reviewed study, but rather from an independent board’s review of Moderna’s results. They reported to the company and to U.S. health officials on Sunday night. Don't expect the full results to be out until December.

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Moderna’s efforts have been part of Operation Warp Speed, the U.S. government’s campaign to pour money into vaccine research. They’ve already invested $2.5 billion in Moderna and purchased 100 million doses for U.S. citizens, according to Science.

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This vaccine isn't identical to the Pfizer shot, though they both work by using the disease's genetic code to spur an immune response, per the BBC.

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The Guardian reports that the Moderna vaccine might be more effective when it comes to protecting against severe COVID, as no vaccinated people in the Moderna trial had serious symptoms. Pfizer's data doesn't discuss this.

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The Pfizer vaccine needs to be kept at -94F, but the Moderna one can be kept at fridge temperatures for a month and at room temperature for up to two hours, Sky News reports. That means it may be more stable and easier to transport.

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Moderna's vaccine will also be more expensive. The Guardian reports that Moderna is selling them to the government for $50-60 for two shots, while Pfizer is charging S40. (President-elect Biden has committed to distributing the vaccine for free.)

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Moderna says that the vaccine appears to work equally well across all racial and ethnic groups, and is also effective in the elderly and people with pre-existing conditions like diabetes, according to Science. There's no data on how would work on pregnant people yet.

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As with the Pfizer-BioNTech vaccine, scientists don’t know how long immunity from the Moderna vaccine will last. The chief medical officer at Moderna, Tal Zaks, told the BBC that the vaccine “does not appear to lose its potency” over time, but it’s too soon to be sure.


Neither vaccine is available to the public yet, because they both need to complete their trials. The FDA, which authorizes vaccines in the U.S., wants both trials to reach around 150 to 165 cases of COVID-19, for statistical accuracy. That will likely happen by December.

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Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told the TODAY Show that vaccines will be available by late December "for individuals in the high-risk category,” from both Moderna and Pfizer. Everybody else will have to wait until 2021.