(Bloomberg) -- U.S. stocks were mixed as more positive vaccine news was offset by signs the deadly virus will hamper economic activity in the shorter term.The S&P 500 Index was little changed after giving up an advance that almost hit 1%. The Nasdaq 100 extended losses into a second day. Earlier gains were driven by news that AstraZeneca Plc became the latest firm to deliver positive vaccine developments. Stocks turned lower as cases continued to surge around the country and New York’s mayor warned the city would be in “dire, dire shape” without additiona federal aid.Trading volume was below the 30-day average at this time of day at the start of the holiday-shortened week. Energy companies topped the leader board after oil moved above $42 a barrel in New York.Data showed U.S. business activity powered ahead in November at the fastest pace since 2015. That helped fuel the rotation into companies that will benefit from a return to normal economic activity, with cruise operators, airlines and retailers posting solid gains.Vaccine successes lately have added to a risk-on mood in markets and investors have snapped up assets that could benefit from the end of lockdowns and travel restrictions. Investors have also started to anticipate Congress will again deliver a spending bill to stave off the economic effects of new restrictions aimed at slowing the virus.“Markets continue to look through the near-term Covid-19 burdens,” said Robert Greil, chief strategist at Merck Finck Privatbankiers. “With political uncertainty in the U.S. fading in addition to the end of the virus tunnel looming, speed bumps for markets become less scary going forward.”U.S. vaccinations against Covid-19 will “hopefully” start in less than three weeks, said Moncef Slaoui, head of the government’s Operation Warp Speed, on CNN’s “State of the Union” on Sunday. An advisory panel of the Food and Drug Administration is meeting on Dec. 10 to discuss emergency use authorizations.Here are some key events coming up:Minutes of the most recent Federal Open Market Committee meeting are due Wednesday.U.S. jobless claims, GDP and personal spending data come Wednesday.U.K. expected on Wednesday to deliver the government’s spending plans for next year.Thursday sees a policy decision and briefing from the Bank of Korea.U.S. celebrates the Thanksgiving holiday on Thursday.The week ends with Black Friday, the traditional start of the U.S. holiday shopping season.These are the main moves in markets:StocksThe S&P 500 Index climbed 0.1% as of 11:26 a.m. New York time.The Stoxx Europe 600 Index was little changed.The MSCI Asia Pacific Index increased 0.2%.CurrenciesThe Bloomberg Dollar Spot Index increased 0.3%.The euro dipped 0.4% to $1.1815.The Japanese yen depreciated 0.6% to 104.53 per dollar.BondsThe yield on 10-year Treasuries rose three basis points to 0.86%.Germany’s 10-year yield advanced one basis point to -0.58%.Britain’s 10-year yield advanced two basis points to 0.322%.CommoditiesThe Bloomberg Commodity Index fell 0.2%.West Texas Intermediate crude climbed 1% to $42.85 a barrel.Gold depreciated 2.1% to $1,832.37 an ounce.For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.