The US has registered more than 1m Covid cases in a single day as the highly transmissible Omicron variant spreads rapidly throughout the country, alarming officials and dashing hopes of a return to normality at the start of 2022.

The 1.08m cases recorded on Monday is the highest daily tally since the start of the pandemic, according to data from Johns Hopkins University, although that number is skewed by a testing backlog from the new year holiday weekend.

Even with the backlog, the number of Covid-19 cases being reported in the US has been at record highs for several weeks, as Omicron has circulated throughout the population. On Monday, the seven-day rolling average of cases reached a record 469,919, according to the Financial Times data tracker, which is double the equivalent figure from a week earlier.