In March the U.S. stock market had significant losses, so yes Covid has impacted the stock market.
I think it's more useful to ask how has Covid impacted tech stocks versus the rest of the market. The top 5 largest companies are all tech stocks, and are about 20% of the S&P 500. When large areas of the U.S. locked down, Amazon did well when they lacked competition from retail stores (which were closed). Cloud services had more usage, where Microsft / Amazon / Google are big players. And so on - tech is doing fine, because everyone can still be a customer from home.
The rest of the market hasn't done as well... and some stocks are particularly hard hit. If you look at restaurant and retail stocks, they are down heavily for the year. But if you look at the overall stock market, it's about break even. And if you look at those big 5 tech stocks, they have incredible gains that are lifting up the overall stock market. So if you break the stock market into smaller parts, you see a different picture than if you look at the whole market.