Shares of Moderna (NASDAQ:MRNA) and Novavax (NASDAQ:NVAX) were jumping 3.7% and 4.4%, respectively, as of 11:23 a.m. EDT on Thursday. Neither company reported any news. However, the gains are likely related to increasing concerns about COVID-19. The major market indexes were sinking Thursday morning after Japan declared a state of emergency for the upcoming Olympic games due to increased COVID-19 cases in Tokyo.
There's a direct connection between the fortunes of vaccine stocks and concerns about COVID-19. When worries increase, the shares of top vaccine makers tend to move higher as well. The longer COVID-19 is a serious issue, the longer the demand will continue for safe and effective vaccines.
Moderna already ranks as a leading supplier of COVID-19 vaccines across the world. Novavax hasn't won approvals or authorizations for its COVID-19 vaccine yet. However, the company has reported positive late-stage results and expects to soon file for authorizations in the U.S., Europe, and U.K.
Why didn't other vaccine makers, particularly Pfizer (NYSE:PFE) and BioNTech (NASDAQ:BNTX), also enjoy solid upswings today? Probably because of recent data from Israel's Health Ministry indicating that the Pfizer-BioNTech vaccine is significantly less effective against the quickly spreading coronavirus delta variant.
The key thing to watch with Novavax is the upcoming regulatory submissions for its COVID-19 vaccine. Investors will also want to monitor any updates related to how well Moderna's and Novavax's vaccines provide protection against the delta variant and other emerging coronavirus strains.