Australian shares were a touch firmer but sentiment was marred by an unabating rise in Delta infections in Sydney, the country's biggest city.
Stronger-than-expected profits from U.S. companies in recent weeks have ratcheted up already high Wall Street forecasts on how second-quarter earnings growth will look versus last year.
Close to 90% of companies listed on the S&P500 have reported positive earnings surprises for the second quarter, according to National Australia Bank economist Tapas Strickland.
Analysts, however, cautioned about the rise in Delta infections of the coronavirus in Asia, with Chinese media reporting 31 provincial regions have warned residents against unnecessary travel in light of recent outbreaks.
China on Wednesday reported 96 new confirmed coronavirus cases for Aug. 3, of which 71 were locally transmitted.
"Wuhan has begun city-wide testing in an eerie echo to the original COVID-19 outbreak," Strickland said.
"While China's resolve to control outbreaks has been well illustrated, markets will continue to watch the outbreak given the high transmissibility of the Delta variant. There are also concerns China's domestic vaccines are less effective against the Delta variant."
Wall Street's main stock indexes were choppy but finished higher with notable gains from Apple Inc, Eli Lilly and Robinhood Markets Inc.
The S&P 500 gained 0.8% to finish at 4,423.15 - another record closing high - while the Dow .DJI rose 0.8% and the Nasdaq added 0.6%.
Investors expect volatility to increase in August as more companies report earnings and the market hears from Federal Reserve officials in coming weeks. U.S. non-farm payroll numbers are due on Friday.
The U.S. dollar eased against the Japanese yen and Swiss franc as questions about slowing U.S. economic growth and the Delta variant challenged risk appetite.
The dollar was near a two-month trough against the yen at 108.95. Against the Swiss Franc, the dollar hovered near its lowest since mid-June at $0.9038.
The New Zealand dollar bolted higher after super-strong jobs data cemented expectations for a hike in interest rates this month. The kiwi swung up to $0.7046, a gain of 1% for the week so far.
The risk sensitive Australian dollar was relatively upbeat at $0.7396, but that was largely due to a positive economic assessment by the country's central bank on Tuesday.
In commodities, Brent futures fell 20 cents to $72.21 a barrel. U.S. crude settled down 32 cents at $70.24 a barrel.
Spot gold was flat at $1,810.4 an ounce.
(Reporting by Swati Pandey in Sydney; editing by Richard Pullin) ((firstname.lastname@example.org; +61 2 9321 8166; Reuters Messaging: email@example.com; twitter.com/swatisays))