Hong Kong's Hang Seng index closed fractionally lower at 26,156.86. Shares of Chinese tech juggernaut Tencent bucked the trend, and surged 4.33% in Hong Kong. That came after the company announced Thursday its quarterly profit rose more than 80% from last year.
In Japan, the Nikkei 225 shed 0.53% to close at 25,385.87 while the Topix index fell 1.33% to end its trading day at 1,703.22.
Meanwhile, shares in Australia declined, with the S&P/ASX 200 down 0.2% to close at 6,405.20.
MSCI's broadest index of Asia-Pacific shares outside Japan rose 0.38%.
Investors continue to monitor the coronavirus situation in the U.S., as daily new cases of the virus continued to rise in the country, setting fresh records.
"From our standpoint, it's just too soon to assess with any confidence the implications of the news for the path of the economy, especially in the near term," Powell said regarding the vaccine.
The U.S. dollar index, which tracks the greenback against a basket of its peers, was last at 92.914 following its rise this week from levels below 92.8.
The Japanese yen traded at 105.05 per dollar, having weakened steeply from levels below 104.3 against the greenback earlier in the trading week. The Australian dollar changed hands at $0.724 after seeing an earlier low of $0.7219.
— CNBC's Fred Imbert contributed to this report.