New Delhi, Dec 22 : Microsoft co-founder and billionaire philanthropist Bill Gates has warned that humanity "could be entering the worst part of the pandemic" as the Omicron variant spreads fast across the globe, stressing that Omicron will "hit home for all of us". In a series of tweets, Gates said that he has cancelled most of his holiday plans as his close friends are increasingly being infected with the Covid-19 virus. "Just when it seemed like life would return to normal, we could be entering the worst part of the pandemic. Omicron will hit home for all of us. Close friends of mine now have it, and I've cancelled most of my holiday plans," Gates tweeted late on Tuesday. The World Health Organisation (WHO) Director-General Tedros Adhanom Ghebreyesus has already said that "an event cancelled is better than a life cancelled," in the wake of Omicron spread. In the US, Omicron is now dominant, accounting for 73 per cent of new infections. "Omicron is spreading faster than any virus in history. It will soon be in every country in the world," Gates said. "The big unknown is how sick omicron makes you. We need to take it seriously until we know more about it. Even if it's only half as severe as Delta, it will be the worst surge we have seen so far because it's so infectious," he posted. Amid mounting cases of the fast-spreading Omicron variant of Covid-19, scientists in the UK have called for urgent rules, warning that waiting till New Year to enforce the measures may be "too late". The UK has so far recorded over 37,000 confirmed cases of Omicron, with a majority of cases detected in the last two-three days, and 12 deaths. In India, the Union Health Ministry said on Tuesday that the new Covid variant Omicron is three times more transmissible than the Delta variant. Gates said that if there's good news here, it's that Omicron moves so quickly that once it becomes dominant in a country, the wave there should last less than 3 months. "Those few months could be bad, but I still believe if we take the right steps, the pandemic can be over in 2022," he said in a tweet. /IANS