With the US shattering a single-day record with over 1 million Covid-19 cases this week, the Centres for Disease Control and Prevention (CDC) has estimated that the Omicron variant accounted for 95 per cent of new infections last week.

According to new CDC estimates released late on Tuesday, the swing from Delta to Omicron happened in nearly a month. At the end of November, more than 99.5 per cent of coronavirus infections were Delta in the country.