Coronavirus updates: Virus can linger in air for hours, CDC says

The CDC posted new guidance on its website warning people about airborne spread.

A pandemic of the novel coronavirus has now killed more than 1 million people worldwide.

Over 35.3 million people across the globe have been diagnosed with COVID-19, the disease caused by the new respiratory virus, according to data compiled by the Center for Systems Science and Engineering at Johns Hopkins University. The criteria for diagnosis -- through clinical means or a lab test -- has varied from country-to-country. Still, the actual numbers are believed to be much higher due to testing shortages, many unreported cases and suspicions that some national governments are hiding or downplaying the scope of their outbreaks.

The United States is the worst-affected country, with more than 7.4 million diagnosed cases and at least 210,013 deaths.

California has the most cases of any U.S. state, with more than 833,000 people diagnosed, according to Johns Hopkins data. California is followed by Texas and Florida, with over 791,000 cases and over 717,000 cases, respectively.

More than 190 vaccine candidates for COVID-19 are being tracked by the World Health Organization, at least seven of which are in crucial phase three trials.

1 in 5 U.S. hospitals have 80% of ICU beds filled: FEMA

COVID-19 cases are on the rise in a majority of states, according to an internal FEMA memo obtained by ABC News.

Based on data from Sept. 28 to Oct. 4, there are 33 states and territories that are on an upward trajectory of new cases, with 19 states seeing a decrease in cases while 4 jurisdictions are at plateau, the memo said.

Roughly 20% of hospitals across the country have more than 80% of their ICU beds filled, according to the memo.

The national positive rate rose from 4.4% to 4.7% during that time frame, according to FEMA.

However FEMA said the 301,308 new cases confirmed between Sept. 28 and Oct. 4 represent a 2.5% decrease from the previous seven-day period.

There were 4,871 deaths recorded between Sept. 28 and Oct. 4, which is a 8.2% decrease in deaths compared with the previous week.

ABC News' Josh Margolin contributed to this report.

AMA warns people to remain cautious

The head of the American Medical Association released a statement following President Trump's tweet that Americans have nothing to fear from the coronavirus.

AMA President Susan R. Bailey noted that in addition to more than 200,000 deaths in the U.S., the virus has caused suffering and long-term problems for many of the 7 million who have contracted it.

"We know vigilance is the best response to the COVID-19 pandemic because this virus doesn't feed on fear; it feeds on complacency," she said in a statement.

Bailey urged Americans to wear masks, wash their hands and social distance.

"We can’t lose sight of our country’s founding motto: E pluribus unum -- out of many, one – and resolve to defeat this virus together," she said.

-ABC News' Victoria Moll-Ramírez

US surpasses 210,000 deaths

The U.S. death toll from COVID-19 has now surpassed 210,000, according to data compiled by the Center for Systems Science and Engineering at Johns Hopkins University.

The death toll reached 200,000 on Sept. 22 and continues to climb as several locations around the country see rises in cases.

The U.S. leads the world in COVID-19 deaths, followed by Brazil, which has over 146,000 and counting, and India, which has over 102,000 and counting.

CDC reposts warnings about airborne transmission

After a back and forth last month, the U.S. Centers for Disease Control posted new guidance Monday on its website once again warning people about airborne spread of the coronavirus.

The updated guidelines state some infections can be spread by exposure to the virus in small droplets and particles that can linger in the air for minutes to hours.

The CDC added that those transmissions can take place, "within enclosed spaces that had inadequate ventilation. Sometimes the infected person was breathing heavily, for example while singing or exercising."

"Today’s update acknowledges the existence of some published reports showing limited, uncommon circumstances where people with COVID-19 infected others who were more than 6 feet away or shortly after the COVID-19-positive person left an area," the agency said in a statement.

The updated language does not change CDC recommendations on social distancing, mask wearing, avoiding large gatherings, and conducting any event or gathering outside as much as possible.

The new guidance came a month after the agency was criticized for posting guidance on airborne transmission on its site and then removing it two days later.

John Brooks, the chief medical officer for CDC’s COVID-19 response, apologized for the changes during a Sept. 21 briefing and told reporters that the initial posting went up too early since they were still conducting a scientific review.

-ABC News' Stephanie Epps