What happened 

Shares of video game stocks Activision Blizzard (NASDAQ:ATVI) and Take-Two Interactive (NASDAQ:TTWO) plunged on Monday, after investors got word that Pfizer's vaccine has been highly effective in a large clinical trial. Activision was down as much as 9.5% today, and Take-Two dropped as much as 10.8% before shares of the video game stocks closed down 4.3% and 8.7%, respectively. 

Shares of Roku (NASDAQ:ROKU) followed the video game drop and were down 12.8% at their low before closing down 12.4%. Apparently, if the pandemic is nearly over, people will be playing video games and watching TV less, or so the market thinks today. 

Video game controller on a table.

Image source: Getty Images.

So what 

The good news is that Pfizer's vaccine trials are going well and the company plans to have millions of vaccines available by the end of 2020. And that could be the start of returning consumers and businesses to more normal activities sometime in 2021. But that's being seen as a bad move for the video game and streaming industries. 

To understand today's move, we have to look back on 2020. Investors have been pushing shares of Activision, Take-Two, and Roku higher on the theory that people will be spending more time playing video games and streaming shows, which should be good for their businesses. The problem is that it hasn't led to particularly impressive growth for Activision Blizzard or Take-Two, although Roku has fared better. 

ATVI Chart

ATVI data by YCharts

Ironically, revenue for video game stocks is down in 2020, and there hasn't been evidence that the pandemic is going to lead to a surge in demand. And that's under what should be considered almost ideal conditions for video game companies.

As for Roku, the company is growing and producing more innovative devices each year. But today the market has decided to sell off stocks it perceives to be benefiting from the pandemic, and this is one that's been hit hard. 

Now what 

I think today's move is all three of these stocks coming back down to earth a little bit after a strong year. I wrote in August that Activision Blizzard is no longer really a growth stock, despite being priced like one. And the same could be said for Take-Two. 

The one stock that I think is being thrown out unfairly with the market is Roku, which is performing well, pandemic or no pandemic. This sell-off could be an opportunity to get shares on sale today, although we should keep in mind that more volatility is ahead and this pandemic is far from over in the U.S. or around the world. 

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.