The major futures indexes are off their worst levels, indicating a decline of 2.2 percent or more than 500 Dow points.
At one point, Dow futures were down 900 points.
Shares are lower following the worst week for Wall Street in nearly three months.
Stocks are turning wobbly as investors re-evaluate their expectations for economic growth, which many skeptics have been saying were overly optimistic.
Case numbers are still growing in various nations, including emerging economies, and without a vaccine, relaxing lockdowns and reopening travel could bring on further waves of COVID-19 cases.
In Asian markets on Monday, Japan's benchmark Nikkei dropped 3.5 percent, Hong Kong's Hang Seng fell 2.2 percent, while China's Shanghai Composite was down 1 percent.
In Europe, London's FTSE fell 0.9 percent, Germany's DAX declined 0.9 percent and France's CAC gave up 0.8 percent.
|I:DJI||DOW JONES AVERAGES||31270.09||-121.43||-0.39%|
|I:COMP||NASDAQ COMPOSITE INDEX||12997.751682||-361.04||-2.70%|
On Wall Street Friday, the S&P 500 rose 1.3 percent a day after dropping nearly 6 percent in its biggest rout since mid-March. It lost 4.8 percent for the week, snapping a three-week winning streak for the benchmark index.
The Dow Jones Industrial Average rose 1.9 percent and ended the week with a 5.6 percent loss after slumping nearly 7 percent on Thursday.
The Nasdaq, which climbed above 10,000 points for the first time on Wednesday, gained 1 percent.
Benchmark U.S. crude oil lost 61 cents to $35.67 a barrel in electronic trading on the New York Mercantile Exchange. It fell 8 cents to settle at $36.26 a barrel Friday. Brent crude oil, the international standard, fell 30 cents to $38.43 a barrel.
The Associated Press contributed to this article.