The first U.S. clinical trial for a novel coronavirus vaccine began yesterday, based on a formulation selected by Moderna Therapeutics and the National Institute of Allergy and Infectious Diseases (NIAID).

Between the lines: Moderna was the first biotech unicorn, valued by venture capitalists at $3 billion in early 2015, before later going public in the largest-ever IPO for a development-stage biotech. We wanted flying cars, but instead we maybe got a civilization-saver.

Moderna wasn't just a VC-backed startup. It was a VC-created startup, inside an incubator program run by Cambridge, Mass.-based Flagship Pioneering. It didn't even have a name for the initial nine months of its life, just a project number.

Here's the basic concept, as I wrote in 2015 for Fortune:

Moderna’s core technology is designed to help people make medicines within their own cells, rather than create something in a lab which patients need to ingest or inject (i.e., the way other biotech works). It does so by injecting messenger RNA into the body, and then that mRNA stimulates the person’s cells to create the needed therapeutic proteins. Patient, heal thyself. Equally important, Moderna claims that its mRNA design is able to evade the typical human immune response that has felled past mRNA efforts.

Not only does this open up a massive number of therapeutic possibilities, but it also could make Moderna’s products significantly faster to test and cheaper to buy. Namely because it can use common mRNA manufacturing facilities and processes to create the mRNA that can be used for all sorts of indications, rather than having to create discrete ones for each new candidate (as is typically done today).

Noubar Afeyan, Flagship's founder and a Moderna board member, tells me that the "faster to test" part is a big reason why the company was able to already push its vaccine into Phase 1 clinical trials. He also believes that, if proven safe and effective, it could hit market sooner than would other, more traditionally developed vaccines (even after adjusting for government fast-tracking).

Caveat: Moderna hopes that the trials, which are being run by the NIH, could reach Phase 3 by the fall. If all endpoints are met, that could mean a vaccine by this time next year.

Moderna had been collaborating for several years with NIAID on developing coronavirus vaccines, and even had been preparing for a 2020 "pandemic test" whereby it would see how quickly it could design, develop, and mass manufacture a global vaccine.

All of that changed in early January, when Chinese authorities disclosed the genetic code for this new coronavirus.

Moderna refocused all of its coronavirus work toward COVID-19, with CEO Stéphane Bancel telling Axios: "Everything else would be a disruption and waste of time."

Within just a few days, Moderna had designed a vaccine on its computers, without access to the virus itself.

The bottom line: Moderna is not the only company working on a vaccine. Just today came reports that Pfizer is in talks with Germany's BioNTech about a joint development deal, and some biotechs are testing vaccines previously developed and approved for other diseases (including alt coronavirus strains). But Moderna's candidate is the first to clinical trials, and serves as a reminder that not all unicorns were founded to help millennials do errands their moms used to do for them.

Go deeper: Coronavirus vaccines in development aren't a short-term cure