Moderna coronavirus vaccine is 94.5% effective, early results suggest

A model of a coronavirus next to a syringe.
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Moderna's experimental coronavirus vaccine is 94.5% effective in protecting against infection with the coronavirus, according to early data released by the Cambridge, Massachusetts-based company Monday (Nov. 16). 

This comes a week after Pfizer's announcement that its vaccine is more than 90% effective, Live Science previously reported.Though the clinical trials from both companies are still in progress and final, peer-reviewed data hasn't yet been published, these results provide some hope as the U.S. faces a record-breaking surge of coronavirus cases. 

Both candidate vaccines shatter public health experts' expectations on efficacy and far exceed the 50% efficacy requirement set by the Food and Drug Administration (FDA) for a vaccine to be approved.

Related: Most promising coronavirus vaccine candidates

These early results were based on an early analysis conducted by an independent Data Safety Monitoring Board (DSMB), appointed by the National Institutes of Health (NIH). The analysis was based on 95 participants in Moderna's phase 3 trial who developed COVID-19. 

Of these 95 cases, 90 were among participants who received a placebo and five were among those given the vaccine, suggesting that the vaccine is 94.5% effective in preventing COVID-19. Among the 95 cases, 15 were people who were 65 years old and older and 20 were among people from diverse communities, according to Moderna.

What's more, in this group of participants, 11 had severe cases of COVID-19, but none of these severe cases were among those given the actual vaccine. (Pfizer did not yet report whether its vaccine protected against severe disease.) The DSMB also didn't report any significant safety concerns in this group of people; adverse events were generally mild or moderate, according to the statement.

The data is "striking" and "quite impressive," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID) told NBC News' "TODAY show," on Monday (Nov. 16). "Now, we have two vaccines that are really quite effective."

"I think this is a really strong step forward to where we want to be," in terms of getting control of the outbreak, Fauci added. 

Both companies use a technology that hasn't yet been used in any approved vaccine to date: A genetic messenger called mRNA prompts the body to create the coronavirus' "spike protein." Traditional vaccines, on the other hand, supply the spike protein to the body rather than teach the body to create one, according to a previous Live Science report. In both cases, the immune system learns to recognize the spike protein and builds an arsenal of cells to fight the virus if the person is ever exposed to it. Fauci predicts that other vaccines, that use these different platforms than mRNA, will also be effective.

Pfizer and Moderna's vaccines, both given in two doses, seem to be similar in safety and efficacy. But Pfizer's vaccine needs to be stored in ultra-cold temperatures of minus 94 degrees Fahrenheit (minus 70 degrees Celsius), whereas Moderna's needs to be stored at minus 4 F (minus 20 C). 

Moderna's vaccine remains stable for up to six months at that temperature, up to 30 days at refrigerated conditions of 36 F to 46 F (2 C to 8 C) and up to 12 hours at room temperature the company said in a separate statement released today. In contrast, Pfizer's vaccine lasts for five days in refrigerated conditions (such as those commonly available in hospitals), according to Reuters.

"Help is on the way," Fauci said on the TODAY show. "But the fact that help is on the way should spur us even more to double down on some of the public health measures," such as social distancing, washing hands, avoiding crowds and wearing masks, he said. Fauci predicted that by the end of December, there could be doses of vaccines from both Moderna and Pfizer available for higher risk people. For all Americans, a coronavirus vaccine could be available by April, Fauci previously said, according to a Live Science report.

Moderna's phase 3 trial, conducted in collaboration with the NIAID and the Biomedical Advanced Research and Development Authority (BARDA), including more than 30,000 people, is still continuing, as is Pfizer's. The government's Operation Warp Speed gave Moderna $955 million for research and development of its vaccine, whereas Pfizer didn't take any money from the government for research and development for its vaccine, according to The New York Times. However, the U.S. government has promised to buy hundreds of millions of doses of both vaccines if and when they are approved. 

Pfizer expects to produce up to 1.3 billion doses of its vaccine globally in 2021, and Moderna expects to produce 500 million to 1 billion doses globally in 2021. Both Moderna and Pfizer started their phase 3 trials on July 27, and in the coming weeks, both expect to have final results and file for emergency use authorizations (EUAs) — permission granted to unapproved products to be used in an emergency such as during a deadly pandemic.

Originally published on Live Science.

Yasemin Saplakoglu
Staff Writer

Yasemin is a staff writer at Live Science, covering health, neuroscience and biology. Her work has appeared in Scientific American, Science and the San Jose Mercury News. She has a bachelor's degree in biomedical engineering from the University of Connecticut and a graduate certificate in science communication from the University of California, Santa Cruz.