What happened

Moderna (MRNA -3.00%) closed nearly 6.5% higher on Wednesday thanks to the results of an early-stage clinical study of its coronavirus candidate on older patients.

In the study, mRNA-1273 was found to produce the neutralizing antibodies that should immunize the body against the coronavirus. It also did so at levels comparable to those of younger patients who have received the vaccine, and without serious adverse effects.

So what

News of mRNA-1273 has been consistently positive, with all clinical research so far indicating that it is efficacious. It's particularly encouraging that this seems to apply to older patients too, as they are considered to be especially vulnerable to the coronavirus, and more broadly because vaccines in general tend to be less effective in older people.

A coronavirus colony.

Image source: Getty Images.

Moderna is considered by many pundits and analysts to be the leader in the race to develop a coronavirus vaccine, and this latest scrap of news will enhance its standing. 

Now what

While Moderna's news is certainly heartening for investors, they should keep a few caveats in mind.

First, this was a very limited study of only 20 people, and its results have yet to be published in a peer-reviewed journal. Second, as a young biotech, the company has never brought a product to market. Finally, there is a long road from the late-stage testing mRNA-1273 is entering to approval, and there's no guarantee it will be proven sufficiently efficacious, let alone given the green light from regulators.