Stocks are ending lower as Wall Street takes a pause after a four-day winning streak. The S&P 500 index fell 0.6%.
Coronavirus counts are rising at a worrying degree in many countries around the world, and Johnson & Johnson said late Monday it had to temporarily pause a late-stage study of a potential COVID-19 vaccine.
Uncertainty about the prospects for more stimulus for the economy from Washington is also hanging over markets.
Several big companies kicked off the earnings reporting season with better profit reports than expected. Analysts are looking for improvement generally from the spring.