Could Pfizer and Moderna Now Face Their Second-Worst Scenario?

Think back to one year ago. No one knew then whether any of the COVID-19 vaccines in development would actually work. Fortunately, several of them did.

Pfizer (NYSE:PFE) (along with its partner, BioNTech (NASDAQ:BNTX)), and Moderna (NASDAQ:MRNA) never experienced the worst-case scenario of their vaccines failing miserably. These companies have gone on to generate billions of dollars in sales for their respective vaccines, and hope to make a lot more money.