What happened 

Shares of Novavax (NVAX -4.32%) were down by 10.4% on Wednesday, even though the vaccine maker did not report any news, and the stock market was up today. A possible explanation is that while the biotech company has been racing to develop a vaccine for COVID-19, Gilead Sciences (GILD 3.62%) has announced positive results from a phase 3 clinical trial for remdesivir as a potential treatment for the disease. And so investors are less confident that Novavax will make a fortune off its potential COVID-19 vaccine. 

So what

Gilead's remdesivir has been considered the most promising potential treatment for COVID-19. Back in February, the National Institutes of Health (NIH) started a phase 3 clinical trial investigating the safety and efficacy of remdesivir as a treatment for the coronavirus. Today, both Gilead and the NIH announced positive results from this trial.

Face mask with COVID-19 written on it.

Image source: Getty Images.

According to the NIH, the data from the trial showed that "remdesivir was better than placebo from the perspective of the primary endpoint, time to recovery." The trial indicates that COVID-19 patients who were treated with remdesivir recovered 31% faster than those treated with a placebo.

Now what

Even if remdesivir is approved as a treatment for COVID-19, Novavax's efforts to develop a vaccine may not go to waste, since that would mean there is both a vaccine to prevent the disease and a drug to cure it. So if Novavax's sell-off on the stock market today is indeed linked to the news of Gilead's successful clinical trial, it is a bit of an overreaction. 

With that said, the race to find a vaccine for COVID-19 remains crowded. With at least 70 vaccines for the illness currently in development, there's no good reason to think Novavax will win that race.