What happened Shares of Moderna (NASDAQ: MRNA) and BioNTech (NASDAQ: BNTX) fell 5.2% and 7.5%, respectively, on Monday after rival COVID-19 vaccine maker Novavax (NASDAQ: NVAX) announced favorable clinical trial results. So what Novavax's vaccine candidate, NVX-CoV2373, demonstrated overall efficacy of 90.4% in a phase 3 study with nearly 30,000 participants. The drug was also shown to provide 100% protection against moderate and severe forms of COVID-19. Additionally, it was generally well-tolerated among the trial's participants. "These data show consistent, high levels of efficacy and reaffirm the ability of the vaccine to prevent COVID-19 amid ongoing genetic evolution of the virus," Novavax president of research and development Gregory Glenn said in a press release. Image source: Getty Images. These results are close to those that were achieved by the Moderna and Pfizer/BioNTech vaccines. Novavax could thus emerge as a formidable new competitor to the leading COVID-19 drugmakers. "Our vaccine will be a critical part of the solution to COVID-19," Glenn said. Now what Novavax intends to file for regulatory authorizations in the third quarter. The biotech said it could manufacture 150 million doses per month by the end of this year. While some countries, such as the U.S., have already acquired the vaccine doses they need, many other countries have yet to do so. Novavax could thus see strong demand for its vaccine in international markets -- and potentially wrestle away some market share from Moderna and BioNTech. 10 stocks we like better than NovavaxWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Novavax wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of June 7, 2021 Joe Tenebruso has no position in any of the stocks mentioned. The Motley Fool recommends Moderna Inc. The Motley Fool has a disclosure policy.Source