Shares of Zoom plunged by roughly 16% in early trading Monday amid promising news about a COVID-19 vaccine. Other “stay-at-home” stocks also saw big declines.

Pharmaceutical companies Pfizer and BioNTech said Monday that their vaccine candidate appeared to be over 90% effective in preventing COVID-19, impacting the value of a company that surged in popularity after almost a year of lockdowns and quarantines.

Pfizer Chairman Dr. Albert Bourla said it was a "great day for science and humanity." 

Meanwhile, shares of Amazon fell by 1.8% and Netflix shares also fell by 4.7%.

Entering Monday's trading, Zoom shares had spiked by more than 600% this year, while Amazon was up close to 80% and Netflix had gained nearly 60%.

"The more the coronavirus makes in-person interactions dangerous, the more valuable Zoom is," tweeted Justin Wolfers, a professor of economics and public policy at the University of Michigan.

"So Zoom's stock crashing can signal that traders believe we're making progress in the war on the virus-like today's news about a potentially powerful vaccine."

Mirroring Zoom's downturn was home exercise company Peloton, which saw its shares fall by 14%.

In a press release, Pfizer and BioNTech said Emergency Use Authorization would be sought from the Food and Drug Administration in the wake of the next safety milestone being completed. 

The companies said that current projections indicate they could produce up to 50 million vaccine doses in 2020 and up to 1.3 billion doses in 2021, although tests continue.

President Donald Trump, who on Saturday lost his reelection bid, reacted on Twitter. "STOCK MARKET UP BIG, VACCINE COMING SOON. REPORT 90% EFFECTIVE. SUCH GREAT NEWS!" Trump tweeted.

As of 11:38 a.m. ET on Monday, the Dow Jones Industrial Average was up 3.92% and hit an all-time high. The S&P 500 gained 2.87%, while the Nasdaq Composite climbed 1.18%.

wall street In this file photo a Wall Street sign is seen near the New York Stock Exchange (NYSE) on May 8, 2020, in New York. Photo: AFP / Johannes EISELE