What happened

Shares of Novavax (NASDAQ:NVAX) dropped 12.7% this week as of the market close on Thursday. The primary reason behind this decline appears to be increasing concerns about the rise of coronavirus variants, especially the highly contagious delta variant.

So what

It would make sense for vaccine stocks to sink if there were reason to believe that they don't work against new coronavirus variants. However, there hasn't been any data thus far about how Novavax's NVX-Cov2373 vaccine fares against the delta variant, the most concerning of the emerging variants.

Coronavirus virions with a stock chart trending down.

Image source: Getty Images.

This lack of information about the efficacy of Novavax's vaccine against the delta variant seems to be troubling investors to some extent. On the other hand, continued worries about COVID-19 fueled by the rise of new variants could translate to a greater market opportunity for the company if its vaccine proves to be highly effective at protecting against the variants.

Now what

The most important milestone for Novavax at this point is to get its vaccine on the market. Novavax plans to file for regulatory authorizations in the U.S., U.K., and Europe in the third quarter of this year. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.