Certain features of the Omicron variant, including its global spread and large number of mutations, suggest it could have a major impact on the course of the Covid-19 pandemic, said the chief of the World Health Organization (WHO).

With the Omicron variant now present in 57 countries, WHO Director-General Tedros Adhanom Ghebreyesus warned at a press briefing that it can spread more rapidly than previous variants, Xinhua news agency reported.