The US has reached a grim milestone of 4 million coronavirus cases, while a quarter of that number came in just the last 15 days.

Iran Press/America: The US on Thursday surpassed 4 million officially recorded Covid-19 cases -- and a quarter of that count came in just the last 15 days.

The total number of infections has doubled in just six weeks as deaths and hospitalizations continue a sharp rise in many states, CNN reported.

The country's rising daily rate of confirmed coronavirus cases, along with a near-record number of hospitalizations, signals the US is far from containing a virus that is straining hospitals and labs, health experts say.

Positivity rates are at alarming levels in numerous states, hospitalizations are soaring, and for the third straight day on Thursday, more than 1,000 new coronavirus deaths were reported, according to Washington Post tracking.

The rolling seven-day average of infections has doubled in less than a month, reaching more than 66,000 new cases per day Wednesday. 

About 59,600 people were hospitalized with COVID-19 in the US on Wednesday -- roughly 300 short of the country's peak recorded in mid-April, according to the COVID Tracking Project.

The US has officially recorded 4,032,430 cases, according to Johns Hopkins University. At least 144,167 people have died.

It took the country nearly 100 days to count its first 1 million cases, from January 21 to April 28. It took only 15 days to rise from 3 million on July 8 to more than 4 million, according to JHU figures.

Many COVID-19 illnesses went undiagnosed, especially early in the pandemic when testing was less available. The Centers for Disease Control and Prevention has said true case totals are probably more than 10 times greater than official figures in most places. One study suggested the US might have had more than 8 million cases in March alone.

But physicians are sounding alarms about rising hospitalizations nationwide, and especially in the nation's hot spots like parts of Florida.

More than 50 hospitals there have reached capacity in their intensive care units, and only 15% of the state's ICU beds are available, the Agency for Health Care Administration said.

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