* Dow Jones Industrial Average down 0.1%, S&P 500 flat * European stocks gain 0.3% * Sterling gains 1.2% as Brexit talks extended * Euro up 0.3% * Eyes on U.S. Congress, Fed for stimulus guidance * Graphic: 2020 asset performance tmsnrt.rs/2yaDPgn NEW YORK, Dec 14 (Reuters) - Global stock markets were mixed on Monday as the start of the COVID-19 vaccine roll-out in the United States offered some respite to investors, but spikes in infection and death rates tempered optimism. Currency markets were dominated by news that London and Brussels had agreed to “go the extra mile” to try to salvage a Brexit trade agreement, lifting the British pound and euro against the struggling dollar. Progress on coronavirus vaccines boosted sentiment, with the first doses being shipped across the United States as part of an effort to inoculate more than 100 million people by the end of March. However, some traders noted that optimism about the vaccine had already been factored in, limiting upside for investors. “We’ve been trading off the same vaccine headlines for three or four months and eventually you’ve got to think that most of that is priced in,” said Dennis Dick, a trader at Bright Trading LLC. “This market is 100% relying on this vaccine”. Second waves of the pandemic forced Germany, the Netherlands and London back into stricter lockdowns. Cases surged in Japan, South Korea and parts of the United States as well. “The vaccine has and will likely continue to provide a tailwind to the market that is allowing investors to look beyond record case levels, hospitalizations and deaths,” analysts at JPMorgan said in a note. U.S. stocks showed modest gains. The Dow Jones Industrial Average fell 43.05 points, or 0.14%, to 30,003.32, the S&P 500 lost 0.88 point, or 0.02 percent, to 3,662.58 and the Nasdaq Composite added 101.51 points, or 0.82%, to 12,479.38. Europe’s broad FTSEurofirst 300 index added 0.30%, at 1,513.23. MSCI’s broadest index of Asia-Pacific shares outside Japan fell 2.47 points, or 0.38%, to 642.04. In currencies, Sterling was the day’s big mover, gaining on both the euro and the dollar as what last week had appeared to be evaporating prospects of a Brexit agreement came back to life. The pound was last trading at $1.3335, up 0.85% on the day after earlier climbing 1.2% to $1.3423. The euro was last up 0.30 percent, at $1.2147. “Even in the face of amped up rhetoric, we continue to think a deal is the most plausible outcome,” said Gilles Moec, AXA Group chief economist. The dollar index, which tracks the greenback versus a basket of six currencies, fell 0.261 point, or 0.29 percent, to 90.715. The yen was last up 0.05 percent, at $104.0600. The Federal Reserve’s policy meeting on Dec. 15-16 will be an added hurdle for the dollar. The market is assuming the central bank will merely refine its forward guidance on policy rather than buying more bonds or “twisting” its portfolio to add longer-dated debt. The Bank of England on Thursday and the Bank of Japan on Friday will close out central bank meetings for 2020. Before that, Wednesday brings the global flash PMIs and on Tuesday, China will issue its monthly data. “The risk is then if the Fed does unveil a surprise twist at this meeting, then Treasuries could rally and the USD could fall,” said Tapas Strickland, a director of economics at NAB. An extra wrinkle is the chance of a U.S. deal on fiscal stimulus after a top Democrat hinted a compromise was possible to get an agreement past Republican objections. Negotiators in the U.S. Congress were nearing agreement on a massive government spending deal that would avoid a government shutdown and could serve as the vehicle to pass a fresh round of aid to a coronavirus-hit nation. Gold prices slid on Monday as the rollout of a COVID-19 vaccine in the United States drove optimism in wider financial markets, with investors banking on a resultant economic recovery. Spot gold prices fell $12.5172 or -0.68 percent, to $1,826.51 an ounce. U.S. gold futures settled down 0.6% at $1,832.10 Oil prices eased on Monday as persistent oversupply in the market overshadowed hopes that a rollout of coronavirus vaccines will lift global fuel demand. Brent crude for February delivery settled up $0.32, or up 0.64 percent, at $50.29 a barrel. U.S. crude settled up $0.42, or up 0.9 percent, at $46.99 per barrel.