SHANGHAI, July 21 (Reuters) - Asian shares and U.S. Treasury yields rose on Wednesday, clawing back some of the week"s losses as investors reassessed economic worries, but the dollar was firm on concerns over the impact of a fast-spreading coronavirus variant. Rising COVID-19 infections have rocked global markets this week as investors dumped risk assets, seeking stability in safe haven assets like bonds. That sent stocks tumbling and pushed the benchmark U.S. 10-year yield to five-month lows on Tuesday. But on Wednesday, MSCI"s broadest index of Asia-Pacific shares outside Japan (.MIAPJ0000PUS) was up 0.17%, trimming its losses for the week to around 2%, while Japan"s Nikkei (.N225) rose 0.90% after touching six-month lows a day earlier. Sentiment in Japan was supported by a jump in exports in June, led by U.S. demand for cars and China-bound shipments of chip-making equipment, boosting hopes for an export-led recovery. read more Australian shares (.AXJO) were up 1.21%, Chinese blue-chips (.CSI300) added 0.76% and Taiwan shares (.TWII) rose 0.27%. Seoul"s KOSPI (.KS11) slipped 0.14% as South Korea reported a daily record of novel coronavirus cases. read more "The level of volumes, the level of sporadic whip-saw price action I think is telling you that there"s not a lot of conviction one way or another," said Kay Van-Petersen, global macro strategist at Saxo Capital Markets in Singapore. But while he said peak global growth had likely passed, easy central bank policies continue to provide strong support for global asset prices even as they begin to flag the tapering of asset purchases. "The G4 central banks" balance sheets have been compounding by 15% since 2008. And my point is that"s not going to stop. It"s not going to get shut off." On Tuesday, the Dow Jones Industrial Average (.DJI) rose 1.62% to 34,511.99 points, the S&P 500 (.SPX) gained 1.52% to 4,323.06 and the Nasdaq Composite (.IXIC) added 1.57% to 14,498.88. The rise in share market gauges in Asia on Wednesday was matched by a fall in U.S. Treasuries prices, with the 10-year yield rising to 1.2202% from the previous day"s close of 1.209%. The 2-year yield was at 0.2036%, up from a close of 0.194%. But pointing to persistent worries around the impact of a surge in global COVID-19 infections, the dollar stayed near three-month highs on Wednesday. "While some of the world is shrugging off rising infections as vaccination rates limit the severity of any symptoms of new cases, there are few parts of the world that can totally ignore this," said Rob Carnell, Asia-Pacific chief economist at ING. The dollar index edged up 0.07% to 93.030, with the euro down 0.07% to $1.1771. The dollar was 0.05% stronger against the yen at 109.90. Oil prices resumed falls after a rebound on Tuesday, with U.S. crude down 0.4% at $66.93 per barrel and Brent at $69.12, down 0.33% on the day. Spot gold shed 0.21% to $1,806.24 an ounce. Reporting by Andrew Galbraith; Editing by Christopher Cushing Our Standards: The Thomson Reuters Trust Principles.