By Kevin Buckland TOKYO, Jan 4 (Reuters) - The U.S. dollar reached its strongest level in nearly five years against the Japanese yen on Tuesday, lifted by a jump in Treasury yields as traders bet on an early Federal Reserve interest rate hike despite surging COVID-19 cases. The greenback rose as high as 115.815 yen for the first time since Jan. 11, 2017, as long-term Treasury yields leapt 12.5 basis points overnight to touch 1.6420% for the first time since Nov. 24. Money markets have fully priced in a first U.S. rate increase by May, and two more by the end of 2022. The dollar index, which measures the currency against the yen and five other major peers, held close to the one-week high of 96.328 reached on Monday. "The market is pricing in a more aggressive U.S. rate hike scenario - or at least the risk thereof - in 2022, and that definitely remains the key support for the dollar," said Shinichiro Kadota, senior FX strategist at Barclays in Tokyo. "The key question for this year is where does inflation go, where does it peak?" The euro traded at $1.1302, lifting off the one-week low of $1.12795 from overnight. Sterling slipped to $1.34685, falling back toward the overnight trough of $1.3431, a level not seen since Nov. 29. The Australian dollar hovered close to a near two-week low of $0.7184 reached in the previous session. While the surge in coronavirus cases caused by the Omicron variant continued to impact global travel and public services, and delay the reopening of some U.S. schools after the holidays, investors remained optimistic that lockdowns would be averted. On Monday, the U.S. Food and Drug Administration authorized the use of a third dose of the Pfizer and BioNTech COVID-19 vaccine for children aged between 12 and 15 years, and narrowed the time for all booster shots to five months from six months after primary doses. Signs that Omicron is highly contagious but leads to less severe illness than variants such as Delta have led to an "Omicron relief trade" buoying stocks and bond yields that could dominate market sentiment through January, OANDA analyst Jeffrey Halley wrote in a note. For dollar-yen, "assuming that U.S. yields remain elevated, there is nothing on the charts to stop a rally to 118.00 in the coming weeks," he said. ======================================================== Currency bid prices at 0552 GMT Description RIC Last U.S. Close Pct Change YTD Pct High Bid Low Bid Previous Change Session Euro/Dollar $1.1302 $1.1299 +0.04% -0.58% +1.1309 +1.1293 Dollar/Yen 115.7800 115.2600 +0.46% +0.67% +115.8100 +115.3400 Euro/Yen Dollar/Swiss 0.9183 0.9186 -0.05% +0.66% +0.9190 +0.9175 Sterling/Dollar 1.3468 1.3481 -0.08% -0.40% +1.3485 +1.3464 Dollar/Canadian 1.2728 1.2746 -0.14% +0.67% +1.2755 +1.2725 Aussie/Dollar 0.7212 0.7191 +0.30% -0.78% +0.7216 +0.7185 NZ 0.6795 0.6788 +0.14% -0.69% +0.6803 +0.6785 Dollar/Dollar All spots Tokyo spots Europe spots Volatilities Tokyo Forex market info from BOJ (Reporting by Kevin Buckland; Editing by Simon Cameron-Moore and Lincoln Feast.)