Over the last couple of months, COVID-19 vaccines developed by Moderna (NASDAQ:MRNA) and Pfizer (NYSE:PFE) along with its partner BioNTech (NASDAQ:BNTX) have been at the center of attention. The two vaccines received emergency use authorization (EUA) in the U.S., U.K., European Union, and other countries. They've already been given to millions of people.

However, there's a new big story in the coronavirus vaccine race. After the market closed on Thursday, another drugmaker announced positive results from a late-stage study of its COVID-19 vaccine. Look out, Pfizer and Moderna: Here comes Novavax (NASDAQ:NVAX).

IMAGE SOURCE: GETTY IMAGES.

A real contender

Novavax's results from its late-stage study conducted in the U.K. should make its COVID-19 vaccine, NVX-CoV2373, a real contender. The biotech reported that its vaccine achieved efficacy of 89.3%.

Sure, that's a little below the 94.1% and 95% efficacy for Moderna's and Pfizer/BioNTech's vaccines, respectively. However, it's definitely close enough to put NVX-CoV2373 in the top tier of COVID-19 vaccines. When full data are available, the small gap could potentially be reduced.

Novavax could also have a distribution advantage. NVX-CoV2373 can be stored in standard refrigerators at temperatures between 36 degrees and 46 degrees Fahrenheit. It's shipped in a ready-to-use liquid formulation. The Pfizer/BioNTech vaccine requires ultracold storage. Moderna's COVID-19 vaccine remains stable at standard refrigerator temperatures for up to 30 days.

Stanley Erck, Novavax's CEO, correctly noted that "NVX-CoV2373 is the first vaccine to demonstrate not only high clinical efficacy against COVID-19 but also significant clinical efficacy against both the rapidly emerging U.K. and South Africa variants." Pfizer/BioNTech and Moderna have released results from test-tube studies that indicate their vaccines should be effective against these new coronavirus variants. However, they haven't reported any results from clinical studies in humans demonstrating efficacy with the U.K. and South Africa variants.

There were some potentially worrisome signs reported by Novavax that could also be concerns for Pfizer and Moderna, though. In a separate phase 2b study conducted in South Africa, NVX-CoV2373 achieved only 60% efficacy in participants who were HIV-negative and 49.4% efficacy overall. Most of the patients who were later diagnosed with COVID-19 were infected with the South African variant. Novavax plans to move forward with clinical studies for boosters and/or combination bivalent vaccines targeting new coronavirus strains.

Still a waiting game in the U.S.

Novavax's announcement is great news for people in the U.K. Clive Dix, interim chair of the U.K. Vaccine Taskforce, called the results "spectacular." It seems very likely that Novavax will soon secure authorization in the U.K. for NVX-CoV2373 based on its positive data.

However, it's still a waiting game in the U.S. Novavax kicked off its Prevent-19 late-stage study of NVX-CoV2373 in the U.S. and Mexico in late December.

Novavax has enrolled and randomized over 16,000 participants in the Prevent-19 study. The company expects that it will complete its targeted enrollment of 30,000 patients in the first half of February. That's encouraging since there have been some concerns about enrollment with two COVID-19 vaccines already available to many Americans.

How long might it be before NVX-CoV2373 could receive EUA in the U.S.? The Food and Drug Administration (FDA) requires monitoring study participants for at least two months after they are fully vaccinated. The second dose of Novavax's vaccine is given 21 days after the first dose. This means that the earliest the biotech would be able to complete its analysis is probably in mid-March. Assuming all goes well, it's possible that NVX-CoV2373 could win EUA from the FDA in April.

Time to buy?

With Novavax's exciting news, is it time to buy the biotech stock? Or is it too late? I've long maintained that Novavax is a good pick. I don't think it's too late to scoop up shares.

I fully expect Novavax to secure authorizations in the U.K. and then go on to obtain authorizations in other countries. The big prize is the U.S. market. Even with the federal government adding to its supply deals with Pfizer and Moderna, I suspect that NVX-CoV2373 will still be on track to win EUA if the results from the late-stage Prevent-19 study are similar to Novavax's U.K. study.

Signs are pointing to COVID-19 becoming akin to the seasonal flu, requiring vaccination on an annual basis. Assuming that's the case, Novavax could realistically generate annual sales of several billions of dollars. It also has a promising flu vaccine headed toward regulatory submission in NanoFlu. The company is exploring the potential to combine its two lead candidates into a combo COVID-19/flu vaccine. I think that could be a huge winner if successful.

One thing is clear, though, after Novovax's announcement on Thursday: Pfizer/BioNTech and Moderna should soon have a formidable rival in the COVID-19 vaccine market.

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