Moderna Says Its Coronavirus Vaccine Is 94.5% Effective Against Covid-19, a Crucial Victory in the Fight Against the Pandemic The announcement closely follows similar news from a rival vaccine program by Pfizer and BioNTech, which touted late-stage success a week ago.

A second experimental coronavirus vaccine has succeeded at preventing Covid-19 in the final stage of clinical research, marking a victory in the fight against the pandemic.

The upstart biotech Moderna announced the success Monday morning in a press release, saying its vaccine was 94.5% effective at preventing Covid-19, the disease caused by the novel coronavirus. An independent group of experts found clear signs of effectiveness after reviewing preliminary data from an ongoing 30,000-person study, Moderna said.

Moderna's shot is the second major vaccine program to announce success in a late-stage trial. Pfizer and its German partner BioNTech said on November 9 that their vaccine was found to be more than 90% effective at preventing Covid-19 in an early review of an ongoing study.

Related: Pfizer Says Its Covid-19 Vaccine Is 90% Effective

Both announcements provide much-needed good news, as the pandemic surges across the world, though it could be weeks before regulators review the shots and decide whether to make them more widely available. The US is now averaging more than 140,000 new coronavirus cases a day, and the healthcare system is showing troubling signs of strain as hospitalizations and deaths rise.

Related: The New Pfizer Vaccine Needs Plenty of Cold Storage, but Will There Be Enough Dry Ice?

Moderna's stock price gained more than 10% before markets opened Monday and was poised to hit an all-time high. US stock futures jumped as well, with the S&P 500 and the Dow Jones Industrial Average gaining 1.4% to 1.8% to trade around session highs.

Pair of 'excellent vaccines'

"Those are two excellent vaccines that are going to help a lot of Americans and help a lot of people around the world," Moderna CEO Stéphane Bancel said in a video interview with Business Insider.

Moderna's release indicates its vaccine is broadly similar to Pfizer's. Moderna said its vaccine appeared to be 94.5% effective, while Pfizer said its shot was more than 90% effective. Moderna's analysis was based on 95 Covid-19 cases, while Pfizer's review included 94 cases. Neither company's data has been published in a scientific journal, and both are still collecting more information on how safe their shots are.

Moderna's study starts counting cases of coronavirus two weeks after volunteers get their second shot, while Pfizer's study records illnesses one week after volunteers finish the vaccination course.

It would be "naïve to compare the 90% to 94.5%," Bancel told Business Insider, saying it's too soon to compare the shots.

Volunteers in Moderna's trial were randomly given a two-dose regimen of either Moderna's experimental shot or placebo injections. The expert panel's conclusion is based on 95 cases of the disease observed in the study.

Out of those 95 illnesses, 90 people on placebo got sick compared with five receiving Moderna's vaccine. The vaccine also appeared to prevent serious illness. Researchers found 11 cases of severe Covid-19 among the placebo group and zero among people who got the vaccine.

Moderna's vaccine has one crucial advantage over Pfizer's shot: It can be stored for a month at typical fridge temperatures (36 degrees Fahrenheit to 46 degrees Fahrenheit), while Pfizer's shot needs to be stored at minus 94 degrees Fahrenheit, requiring dry ice and special containers.

Moderna's vaccine still needs to be evaluated by FDA

Both vaccines are still experimental and need to secure regulatory authorization before being rolled out to the public. Both companies plan to apply for emergency-use authorization later in November. It's unclear how long the US Food and Drug Administration will take to evaluate the shots and decide whether to approve them.

Even if OK'd by regulators, vaccine supply will be extremely limited at first, though having two vaccines would be helpful.

Moncef Slaoui, the chief advisor to the US government's vaccine initiative, called Operation Warp Speed, recently estimated that 20 million Americans could be immunized in December if both shots were approved.

Moderna was a key component of Warp Speed's vaccine plan, with the US government investing up to $2.48 billion to fund its development and secure a supply.

Pfizer has said it hopes to produce up to 50 million doses by the end of 2020, and Moderna should have 20 million doses available in the US by year's end. Both shots are given as two-dose regimens.

Manufacturing will expand in 2021, with Pfizer saying it will have enough of its vaccine to immunize up to 650 million people and Moderna aiming to produce enough shots for 500 million worldwide. Vaccines from other drugmakers could become available next year as well if they succeed in clinical trials that are now underway.

Bancel predicted that a coronavirus vaccine would be widely available in the US by Memorial Day, at the end of May, based only on the results from Pfizer and from his company.

"Even if no other vaccines were going to make it, as a worst-case scenario, I think by Memorial Day, end of June, any Americans who want a vaccine will have their hands on a vaccine," Bancel said.

Early success should bode well for other vaccine frontrunners

The effectiveness of Moderna's shot should bode well for other vaccine frontrunners. All these experimental shots target the same part of the novel coronavirus, the spike protein.

Slaoui told Business Insider in October that he anticipated three waves of approvals over the next few months.

Moderna and Pfizer would make up the first wave. They could quickly be followed by shots from Johnson & Johnson and AstraZeneca. Slaoui said he expected results in December or January from those companies.

The third wave includes two more shots — one by Novavax and the other by Sanofi and GlaxoSmithKline. Those programs are expected to start the final stage of clinical trials in the US within the next few weeks.

Leading government scientists have said a vaccine should be widely available to Americans by April. Slaoui predicted in August that If people agreed to get the shots, we could return to normal in the second half of 2021.

The announcements that both vaccines are effective is a validation for the new technology that both use, called messenger RNA. The technology platform uses only the genetic code of the virus to create a shot. The approach is promising yet novel: There are no federally approved mRNA vaccines to date.

Key questions remain unanswered, despite promising news

It's too early to draw any conclusions on whether one vaccine is more efficacious or safer than the other. While Moderna provided far more detailed results than Pfizer, neither has published data in medical journals from its trials, which remain ongoing.

Both companies are still collecting and analyzing data, which means the exact effectiveness of the shots could differ from these preliminary results.

Moderna gave an overview of preliminary data on safety and side effects, while Pfizer didn't provide that information.

Most side effects from Moderna's shots were mild or moderate, but some volunteers did have severe side effects, which are medically significant but not life-threatening. These happened mainly after the second injection. The most common severe side effects were fatigue (9.7%), muscle pains or aches (8.9%), joint pain (5.2%), headache (4.5%), pain (4.1%), and redness at the injection site (2.0%).

While Moderna said these side effects were "generally short-lived," specific details will be important, particularly in terms of how severe and long-lasting the side effects were.

There are some other unanswered questions.

On efficacy, it's unclear whether either vaccine prevents asymptomatic infections. The studies probably won't be able to answer that question definitively, as volunteers weren't tested for the coronavirus unless they developed symptoms.

Neither company has provided detailed results by age group. Some vaccines have historically been less protective in older people.

Finally, we don't know anything about how long protection might last. That information will only come with more time, as study volunteers are followed for many more months. It's possible people will need to get booster shots, though no one knows whether those would be needed in six months, a year, or several years down the line.

A transformative moment for Moderna

While Pfizer is a pharmaceutical giant known for treatments like Viagra and Lipitor, Moderna is a much smaller biotech upstart that has never developed an approved medication.

Still, Moderna, which has been around for only about a decade, has quickly became one of the buzziest startups in the drug industry.

Bancel, the CEO, has had grand visions of mRNA's potential to work in a wide range of diseases. That has driven record levels of fundraising for Moderna, including the largest biotech initial public offering in history in December 2018.

The Cambridge, Massachusetts, company is working on several other vaccine candidates for Zika, influenza, cytomegalovirus, and respiratory syncytial virus.

Moderna is hoping its coronavirus success proves that the company's foundational technology works, Bancel said.

"It's copy and paste," he said. "So the Zika vaccine, the CMV vaccine, if this vaccine shows high efficacy, they are going to have high efficacy. It's just science."

Responding to the pandemic has accelerated the company's progress, and Moderna has worked closely with the US National Institutes of Health since January to develop and test a Covid-19 vaccine candidate. Moderna's vaccine candidate was the first in the world to start human testing in March.

To be able to have positive efficacy results from a late-stage study in less than a year is a scientific feat so far matched only by Pfizer and BioNTech.

Investors have noticed. Moderna's stock has more than quadrupled this year, driven by its coronavirus vaccine progress. The company has hired hundreds of new employees, particularly to help run its Norwood, Massachusetts, manufacturing plant around the clock.

'It's just the beginning'

The company's success has also drawn criticism. Top company executives and board members sold $236 million in stock over the first nine months of 2020, as some corporate-governance experts criticized the insider sales as bad optics.

And previous press releases about positive early data were criticized by some infectious-disease experts as "science by press release." The eventual data was later published in a top medical journal and was in line with Moderna's initial description.

Despite the criticism, Moderna's late-stage success is the clearest validation of its technology to date.

"It's just the beginning of a big wave of products," Bancel said.

While there are major logistical challenges ahead in the fight against the pandemic, having effective vaccines will go a long way to defeating the virus.