The countdown is on -- and I'm not referring to the U.S. elections. Many Americans anxiously await the results from the first round of coronavirus vaccines that are in late-stage testing.

Positive clinical results should lead to relatively quick emergency use authorization (EUA) from the Food and Drug Administration. It's possible that over the next several months, safe and effective COVID-19 vaccines will become available throughout the U.S. This could be the turning point in ending the pandemic, which has caused more than 200,000 deaths nationwide so far and has severely disrupted the economy.

Pfizer (NYSE:PFE) and Moderna (NASDAQ:MRNA) are the two U.S. companies likely to first announce results from late-stage testing of their respective coronavirus vaccine candidates. But what if either company's results are delayed? Believe it or not, delays could actually be great news. 

Woman wearing a mask holding a large hourglass.

Image source: Getty Images.

Watching the calendar

Pfizer and its partner, German biotech BioNTech (NASDAQ:BNTX), began a phase 3 clinical study of coronavirus vaccine candidate BNT162b2 on July 27, 2020. The companies stated at the time that they could seek regulatory review as early as October if the testing went well. 

On Sept. 12, Pfizer and BioNTech proposed expanding the late-stage study of BNT162b2 to include 44,000 participants instead of the originally planned 30,000 participants. This didn't impact their expected timeline, however. Pfizer and BioNTech reiterated that they "continue to expect that a conclusive readout on efficacy is likely by the end of October."

Moderna shouldn't be too far behind. The company's CEO, Stephane Bancel, stated recently at an industry conference that he expects requesting FDA EUA for COVID-19 vaccine candidate mRNA-1273 on Nov. 25, 2020, pending positive late-stage clinical results. 

There are two other drugmakers with coronavirus vaccine candidates in late-stage testing in the U.S. -- AstraZeneca and Johnson & Johnson. However, AstraZeneca's U.S. testing is still on hold due to a severe reaction with a participant in the company's U.K. clinical trials. J&J started the phase 3 testing of its COVID-19 vaccine candidate less than two weeks ago and doesn't anticipate results until early 2021.

Healthcare professional injecting a patient's arm.

Image source: Getty Images.

Why delays could be great news

You might think that any delays for Pfizer and Moderna would automatically be bad news -- but there's a possibility that potential delays could be great news for Americans.

How? It boils down to what the FDA will require to grant EUA. 

The FDA plans to issue guidance soon about the criteria that must be met for a COVID-19 vaccine to receive emergency use authorization. Although the specifics aren't known yet, there have been leaks about some of the likely requirements.

Two of these potential criteria especially stand out. The FDA will probably require that participants in late-stage clinical studies of COVID-19 vaccine candidates be monitored for a median of two months after the second dose of the vaccine. In addition, the agency is expected to require that the placebo groups of the studies have at least five cases of severe COVID-19.

Pfizer and Moderna can control how they meet the first of these two criteria, but if there aren't enough participants in the placebo group who develop severe cases of COVID-19, they won't be able to seek EUA. 

If this scenario happens, it would mean that nearly all unvaccinated individuals in the late-stage studies aren't being infected by the novel coronavirus. That would be fantastic and point to a significant improvement in how COVID-19 is impacting the country. It would also mean that Pfizer and Moderna would have more vaccinated participants to evaluate the safety profiles of their respective vaccines. This could boost Americans' confidence in the vaccines.

Of course, there's also a possibility that Pfizer or Moderna could delay announcing their late-stage results for internal reasons, such as needing more time to compile and analyze data. This scenario wouldn't necessarily be bad news for Americans, although it would likely impact the companies' share prices.

Stick with the schedule

The odds are almost certainly high that Pfizer and Moderna will hit their announced timelines for reporting late-stage results for their coronavirus vaccine candidates. It would be a near-miracle if very few participants in the companies' placebo groups failed to develop severe cases of COVID-19.

Both companies also know how much is on the line. Major internal missteps that could delay the announcements of their results should be unlikely. And make no mistake about it: There is a lot on the line for both Pfizer and Moderna.

Pfizer and BioNTech stand to receive $1.95 billion from the U.S. government to supply 100 million doses of BNT162b2 if the vaccine wins EUA from the FDA. The supply agreement could be expanded to include another 500 million doses.

Moderna also has a supply deal in place to provide 100 million doses of its COVID-19 vaccine to the U.S., with the option to add another 400 million doses to the total. The biotech stock would undoubtedly skyrocket much higher than Pfizer's shares would if mRNA-1273 secures EUA. 

Look for Pfizer and Moderna to stick with the schedule, and for both companies to potentially reap big rewards for doing so.

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.