What happened

Shares of several COVID-19 vaccine makers were sliding on Monday. BioNTech stock (NASDAQ:BNTX) was down 6.5% at 12:09 p.m. EDT. Shares of Moderna (NASDAQ:MRNA) had slipped 4.4%. Novavax (NASDAQ:NVAX) stock had fallen 6%.

None of these companies had announced any news that would affect their share prices one way or another. So why did the vaccine stocks decline? The primary cause is likely run-of-the-mill volatility.

However, there's also the possibility that recent remarks made by the CEOs of Moderna and Pfizer (NYSE:PFE) raised investors' concerns. Last Thursday, Swiss newspaper Neue Zuercher Zeitung published an interview with Moderna CEO Stéphane Bancel. In the article, Bancel predicted that the pandemic could be over within a year.

Over the weekend, Pfizer CEO Albert Bourla expressed a similar view in an interview with ABC's This Week. Bourla said, "Within a year I think we will be able to come back to normal life."  

A healthcare professional giving a shot to a person.

Image source: Getty Images.

So what

An end to the pandemic could lead to a significant reduction in sales for Moderna and BioNTech. It's unlikely that two doses of the company's vaccines will be needed then. It's still not clear whether ongoing boosters will be needed.

Pfizer's Bourla stated that "the most likely scenario is annual vaccination" for COVID-19. Even if he's right, vaccine sales could decline -- especially if vaccination rates aren't high in a post-pandemic world.

This would be problematic for Moderna, BioNTech, and Novavax. Both Moderna and BioNTech depend entirely on sales of their respective COVID-19 vaccines. Novavax doesn't have authorization or approval to market its COVID-19 vaccine candidate yet. However, the company's prospects could also be reduced once the pandemic ends.

Now what

Expect all three stocks to remain highly volatile. Novavax could have the biggest potential catalysts on the way. The company hopes to file for Emergency Use Authorizations in several countries in the near future. Novavax also awaits Emergency Use Listing for its COVID-19 vaccine from the World Health Organization.

BioNTech and its partner, Pfizer, plan to submit for U.S. EUA for their COVID-19 vaccine in children under age 12 within a matter of days. The companies recently reported positive results from a late-stage study with younger kids.

Moderna hopes to soon win EUA for a booster dose of its vaccine. The company submitted data supporting booster shots with the U.S. Food and Drug Administration (FDA) on Sept. 1, 2021. 

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.