Global coronavirus infections surpassed 2.5 million on Tuesday, according to a Reuters tally, with US cases nearing 800,000.
The figure includes more than 170,000 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.
North America accounts for a third of all cases, though so far the region has reported lower death rates. In both the United States and Canada, 5 percent of reported cases have been fatal.
Cases in Latin America continue to grow faster than other regions, and topped 100,000 in the past 24 hours.
In China, where the virus is thought to have originated, daily new cases have dwindled to less than 20 a day over the past three days and no new deaths have been reported this week.