U.S. stocks opened mixed after a volatile premarket session Tuesday after public health agencies announced a temporary halt in the use of a COVID-19 vaccine from Johnson & Johnson and inflation was stronger than analysts had forecast in March. The Dow Jones Industrial Average /zigman2/quotes/210598065/realtime DJIA +0.66% fell 62 points, 0.2%, to open near 33,684, while the S&P 500 /zigman2/quotes/210599714/realtime SPX +0.74% gained 1 point to open near 4,129. The Nasdaq Composite index /zigman2/quotes/210598365/realtime COMP +0.88% , which contains many of the stocks most in favor in a work-from-home world, added 65 points, 0.5%, to start trading near 13,915. Johnson & Johnson shares /zigman2/quotes/201724570/composite JNJ +0.45% slipped 2.4% after the opening bell. In other biotech news, shares of Novocure Ltd. /zigman2/quotes/201589146/composite NVCR -0.62% skyrocketed after the tumor treatment company reported positive news on its lung cancer treatment. The consumer price index gained 2.6% for the year in March, the Labor Department said.