Global coronavirus infections surpassed 2.5 million, according to a Reuters tally, with US cases crossing 800,000.
The figure includes more than 180,000 deaths, two-thirds of which have been reported in Europe.
It took around 75 days for the first 500,000 cases to be reported, and just six days for the most recent half million to be registered.
It compares to 3 million to 5 million cases of severe illness caused annually by seasonal influenza, according to World Health Organization estimates.
While experts say actual cases of the new coronavirus are likely higher than current reports, the number still falls far short of the Spanish flu, which began in 1918 and infected an estimated 500 million people.
Despite the growing number of cases in the current pandemic, there are signs that the spread of the coronavirus is slowing with many countries exercising lockdown measures.