U.S. stocks opened lower on Thursday as investors watched China's efforts to contain the coronavirus's rapid spread in Asia. The S&P 500 /zigman2/quotes/210599714/realtime SPX +0.97% was down 0.2% to 3,316. The Dow Jones Industrial Average /zigman2/quotes/210598065/realtime DJIA +0.95% shed 117 points ,or 0.4%, to 29,069. The Nasdaq Composite /zigman2/quotes/210598365/realtime COMP +0.16% edged 0.1% lower to 9,372. So far, Chinese officials have announced that three cities including Wuhan have been locked down, preventing residents from leaving. On monetary policy, the European Central bank announced it would keep interest rates unchanged, but ECB President Christine Lagarde said downside risks to the outlook were less pronounced than before. In company news, shares of P&G /zigman2/quotes/202894679/composite PG +0.97% were down after the consumer-products company reported a fiscal second-quarter profit above analyst expectations. Shares of Dow-component Traveler's also fell after its earnings and revenues topped Wall Street estimates.