Coronavirus cases in the US hit four million yesterday, with 2,600 new cases every hour on average, the highest rate in the world.
Infections have rapidly accelerated since the first US case was detected on January 21.
It took the country 98 days to reach one million cases. It took another 43 days to reach two million and then 27 days to reach three million. It has only taken 16 days to reach four million at a rate of 43 new cases a minute.
The federal government, state governors and city leaders have often clashed over the best way to tackle the pandemic, leading to a confusing patchwork of rules on issues like mask-wearing in public and when businesses can open.
US President Donald Trump recently shifted his tone. He had previously been reluctant to wear a mask himself but this week encouraged Americans to wear masks and recently appeared in public for the first time with a face covering.
Of the 20 countries with the biggest outbreak, the United States ranks second for cases per capita, at 120 infections per 10,000 people, only exceeded by Chile.
With over 143,000 deaths, or 4.4 fatalities per 10,000 people, the United States ranks sixth globally for the highest deaths per capita. It is exceeded by the UK, Spain, Italy, Chile and France.
Globally, the rate of new infections shows no sign of slowing, with the disease accelerating the fastest in the United States and South America, according to the Reuters tally, based on official reports.
Brazil registered a new daily record for confirmed coronavirus cases on Wednesday, pushing the total confirmed cases across Latin America past four million.
Brazil has the second-largest outbreak in the world, with more than 2.2 million people testing positive and nearly 83,000 deaths.
India, the only other country with more than a million cases, reported almost 40,000 new cases on Wednesday.
Florida reported a record one-day increase in deaths from Covid-19 yesterday with 173 lives lost, according to the state health department.
The state also reported that cases rose by 10,249, bringing its total cases to nearly 390,000. Total deaths rose to 5,632.
Florida has the third-largest outbreak in the nation, behind only California and New York.
This week the US government set a benchmark for Covid-19 vaccine pricing in a $2bn (€1.7bn) deal announced with Pfizer Inc and German biotech BioNTech SE.
The deal, which depends on approval for the vaccination, secures enough vaccines to inoculate 50 million Americans for about $40 (€34) a person, or about the cost of annual flu jab. It is the first to provide a direct window into likely pricing of successful Covid-19 vaccines.
It also allows for some drugmakers to profit from their efforts to protect people from the virus that has killed some 620,000 people worldwide, almost a quarter of those in the US.
Unlike other vaccine deals signed by the US government, Pfizer and BioNTech will not collect a payment until their vaccine proves to be safe and effective in a large clinical trial expected to start this month.
The US and other governments have previously struck deals to support Covid-19 vaccine development, some of which included guaranteed deliveries of doses. But this is the first deal to outline a price for finished products.
"The average price for a flu vaccine is around $40," said Peter Pitts of the Centre for Medicine in the Public Interest. "It looks good with that comparison. It's well within the ballpark of reasonableness."
Other major experimental vaccines have displayed relatively similar data on safety and efficacy, suggesting that no one drugmaker would be able to charge a lot more than its peers, said biotechnology analyst Vamil Divan.