The Omicron variant of Covid-19 has now been reported in 57 countries, the World Health Organization (WHO) says.

It is still too early to draw any conclusions about the global impact of Omicron, the UN health agency said.

“Features of the new COVID-19 variant Omicron, including the extent to which it will spread, and the sheer number of mutations, suggest that it could have a major impact on the course of the pandemic, but it’s still too early to say for sure,” according to WHO.

WHO Director General, Tedros Ghebreyesus, speaking to journalists in Geneva, highlighted “a consistent picture of rapid increase in transmission” but said that the exact rate of increase relative to other variants remains difficult to quantify.

Despite some data from South Africa suggesting increased risk of re-infection with Omicron, more data is needed. The variant might also cause milder disease than Delta, but there is no definitive answer yet.

“New data are emerging every day, but scientists need time to complete studies and interpret the results. We must be careful about drawing firm conclusions until we have a more complete picture,” Tedros explained.

In this context, the WHO chief called on all countries to increase surveillance, testing and sequencing.

“Any complacency now will cost lives,” he warned.

Even though the world still needs answers to some crucial questions, Tedros said people everywhere are not defenceless against Omicron, or Delta.

“The steps countries take today, and in the coming days and weeks will determine how Omicron unfolds. If countries wait until their hospitals start to fill up, it’s too late. Don’t wait. Act now,” he said.

Tedros also asked countries to avoid “ineffective and discriminatory” travel bans.

This week, France and Switzerland have lifted their travel bans on southern African countries, and Tedros urge other countries to follow their lead.