The FTSE All World index dropped by 2.2 per cent in its worst day since October 2020 with markets in US, Europe and Asia sustaining a bout of heavy selling.
Harbour Asset Management portfolio manager Shane Solly said the market had become complacent about Covid-19, and news of the latest variant was a reminder that it was not going to do down without a fight.
"There is a way to go," he said.
"It may mean a couple of weeks of uncertainty until the labs have found out what it is and whether existing treatments can deal with it," he said.
Travel and travel-related stocks bore the brunt of selling.