Asian shares wavered on Monday amid worries that problems with vaccine rollouts combined with new strains of Covid-19 will delay a global economic recovery that has already been baked into the market's rich valuations.
MSCI's broadest index of Asia-Pacific shares outside Japan fell 0.4 per cent, following four straight sessions of losses. Japan's Nikkei bounced 0.4%, after shedding almost 2 per cent on Friday.
Futures for the S&P 500 lost another 0.7 per cent in heavy trade, while NASDAQ futures fell 0.9 per cent.
Dealers were also warily awaiting new developments in the headline-grabbing battle between retail investors and funds that specialise in shorting stocks.