The coronavirus has now infected more than 1 million people in the United States as the nation grapples with roughly a third of all global cases — making it the worst outbreak in the world, according to data compiled by Johns Hopkins University.

A large portion of U.S. Covid-19 cases remain in New York state, where Gov. Andrew Cuomo is currently testing about 20,000 people a day for the virus and is working with President Donald Trump to double that number.

The virus has touched every state in the U.S., disrupting daily life for millions of Americans as state and local leaders have shuttered nonessential businesses to try to curb the pandemic, putting record numbers of people out of work. Some states are mulling reopening, but U.S. officials said last week that they are preparing to battle two bad viruses circulating at the same time as the coronavirus outbreak runs into flu season next fall and winter.

"There's a possibility that the assault of the virus on our nation next winter will actually be even more difficult than the one we just went through," Robert Redfield, director of the Centers for Disease Control and Prevention, told The Washington Post in an interview published April 21. "And when I've said this to others, they kind of put their head back, they don't understand what I mean."

Health officials and scientists are still learning about the coronavirus, which emerged in Wuhan, China, almost four months ago.

Symptoms of the coronavirus can include a sore throat, runny nose, diarrhea, fever or pneumonia and can progress to multiple organ failure or even death in some cases, according to the World Health Organization. The CDC expanded its list of symptoms last week as scientists gather more data on the coronavirus and patients show "a wide range of symptoms."

The CDC now says chills, repeated shaking with chills, muscle pain, headache, sore throat and a sudden loss of taste or smell are also common indicators of the coronavirus.

The virus can take anywhere from two weeks to eight weeks from the first onset of symptoms before a patient is sick enough to die, the WHO said, citing early data from China. The median time from the first sign of symptoms to recovery for mild cases is approximately two weeks and between three and six weeks for patients with severe or critical disease, according to the WHO.

The virus has been shown to be particularly severe for the elderly and those with underlying health conditions such as diabetes, chronic lung disease and heart disease, according to world health officials and the CDC. Most kids infected with the coronavirus develop only mild symptoms and typically recover within two weeks, however, some do become seriously ill. Healthy young and middle-aged people, with otherwise mild cases of the virus, are said to be dying from strokes.

Scientists across the globe are fast-tracking work to find an effective treatment. There are no proven treatments for Covid-19 and U.S. health officials say making a vaccine will take at least 12 to 18 months.

Meanwhile, federal and state leaders are deploying antibody or serological tests in hopes the results may help guide when they can reopen the economy.

Preliminary results of antibody testing across New York last week showed that 13.9% of state residents carried Covid-19 antibodies, providing the "first true snapshot" of how many people have been infected with the virus across the state.