When Dr. Anthony Fauci speaks, people listen. The director of the National Institute of Allergy and Infectious Diseases (NIAID) quickly became a top spokesperson for the U.S. effort to fight the COVID pandemic earlier this year.

There's one company that Fauci has singled out among the several that are developing COVID-19 vaccine candidates. That drugmaker is Moderna (NASDAQ:MRNA).

And when The New York Times reported a few days ago that the Trump administration has picked five COVID-19 vaccines to receive substantial financial support of the U.S. government, there was one company mentioned first. You guessed it... Moderna.

Is Moderna really the de facto leader in the COVID-19 vaccine race? It's complicated.

COVID-19 vaccine bottles with two bottles lying on their sides

Image source: Getty Images.

First mover among several

On March 16, Moderna became the first to begin a phase 1 clinical study evaluating a COVID-19 vaccine candidate in humans. But it was followed a week later by Chinese drugmaker CanSino Bio

Inovio wasn't too far behind. The clinical-stage biotech began a phase 1 study of its experimental COVID-19 vaccine on April 6.

The University of Oxford dosed the first patients in a phase 1 study of its COVID-19 vaccine candidate on April 23. By the end of April, big British drugmaker AstraZeneca (NASDAQ:AZN) announced that it was partnering with Oxford on the development and commercialization of the vaccine.

Pfizer (NYSE:PFE) and its partner, BioNTech (NASDAQ:BNTX), weren't far behind. The two companies kicked off the phase 1 portion of a phase 1/2 clinical study of a COVID-19 vaccine candidate initially developed by BioNTech on May 5. 

Novavax (NASDAQ:NVAX) jumped into the race on May 25. The clinical-stage biotech also initiated the phase 1 part of a phase 1/2 clinical study. 

Others are in hot pursuit. Johnson & Johnson expects to begin a clinical study of its COVID-19 vaccine candidate by September. Merck, Sanofi, and GlaxoSmithKline are gearing up to begin clinical testing of their experimental vaccines.

A neck-and-neck race

Although Moderna was the first to begin clinical testing of a COVID-19 vaccine candidate, is it still in first place? That's a tough call. It's definitely a neck-and-neck race.

Moderna expects to begin a phase 3 study of its COVID-19 vaccine in July. But Chinese drugmaker CanSino could begin its late-stage study around the same time. 

The AstraZeneca-Oxford team is certainly in the running for the lead position as well. The partners began enrolling for a phase 2/3 clinical study in late May. They haven't stated exactly when the clinical trials will wrap up because of the uncertainty about how long it will take for some participants to develop COVID-19. Results could be available within two months of the study kick-off or up to six months. 

Gloved hand holding COVID-19 vaccine syringe

Image source: Getty Images.

What's harder to determine

It's pretty easy to compare the timelines of each of the companies developing COVID-19 vaccine candidates. What's much harder is to try to determine which of these vaccines have the best chance of success.

The White House chose the vaccines being developed by Moderna, AstraZeneca-Oxford, Pfizer-BioNTech, J&J, and Merck as the most promising candidates. Does this mean that these vaccines are truly the most likely to be successful? Not necessarily. For one thing, it's a mystery why the Trump administration picked J&J and Merck over others that are farther along (namely, Novavax and Inovio).

Another organization that's trying to identify the COVID-19 vaccine candidates with the most promise is the Coalition for Epidemic Preparedness Innovations (CEPI). The nonprofit organization was founded by the Bill and Melinda Gates Foundation, the governments of India and Norway, the Wellcome Trust, and the World Economic Forum. It's also funded by other governments across the world as well as by private sector companies.

CEPI has funded several COVID-19 vaccine candidates so far. But the organization has invested the heaviest in the vaccines being developed by Novavax and AstraZeneca. 

A tricky three-letter word

At least when it comes to the COVID-19 vaccine race, referring to Moderna (or any other company) as the leader is probably premature. "The" is a tricky three-letter word in this case. It's better to instead to view Moderna as a leader in the development of a COVID-19 vaccine.

But we should also view several others as leaders in developing COVID-19 vaccines. I'd put AstraZeneca and the University of Oxford, CanSino Bio, and Novavax on the list for sure. And I wouldn't rule out the Pfizer-BioNTech partnership or Inovio.

What about J&J, Merck, Sanofi, and GlaxoSmithKline? These big pharmaceutical companies certainly have considerable vaccine expertise and the financial resources to quickly advance their COVID-19 vaccine candidates. Because none of them have begun clinical trials yet, I'd be hesitant to refer to them as leaders at this point. However, that could change in the near future.

I fully expect that there will eventually be multiple vaccines that prove to be safe and effective. Moderna is getting the most attention right now, but my view is that the biotech will have to share the limelight.

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.