The U.S. Centers for Disease Control and Prevention updated its guidelines Monday to acknowledge that the coronavirus can spread through tiny, airborne particles that can linger in the air for minutes or hours, particularly in enclosed spaces.

On Monday, CDC guidelines showed COVID-19 can sometimes be spread through airborne transmission. The long-awaited acknowledgement is in line with arguments made for months by researchers and medical experts who have said that wearing masks can reduce potential exposure.

Evidence shows that coronavirus might share similarities with tuberculosis, measles and chicken pox, which are “able to infect people who are further than 6 feet away from the person who is infected or after that person has left the space,” according to the CDC.

“There is evidence that under certain conditions, people with COVID-19 seem to have infected others who were more than 6 feet away,” the CDC guidelines say. “These transmissions occurred within enclosed spaces that had inadequate ventilation. Sometimes the infected person was breathing heavily, for example while singing or exercising.”

In a statement obtained by CNN, CDC officials emphasized that people are more likely to become infected with the coronavirus the longer they stay with and the closer they stay to people who have COVID-19.

“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 statement said. “In these instances, transmission occurred in poorly ventilated and enclosed spaces that often involved activities that caused heavier breathing, like singing or exercise. Such environments and activities may contribute to the buildup of virus-carrying particles.”

The update comes after the CDC removed similar recommendations from its website last month, saying that a draft update to transmission guidance was posted online by mistake. The Washington Post reported officials feared people might think that airborne transmission was the main way people get coronavirus.

The CDC previously said that the predominant way the virus spreads is from person-to-person through respiratory droplets emitted when an infected person sneezes, coughs, talks or breathes. The droplets can land in the mouths or nose of nearby people, spreading COVID-19.

The CDC recommends that people keep at least six feet of distance between themselves and others, wash their hands, avoid crowded indoor spaces, ensure indoor spaces are well ventilated, wear masks when around others and stay home if they’re sick to stymie the spread of the coronavirus.

The United States leads the world with the most coronavirus cases and the highest death toll. Since the start of the pandemic, officials have confirmed more than 7.4 million infections and reported more than 210,000 deaths nationwide, according to numbers compiled by Johns Hopkins University.

As of Monday, more than 35.3 million COVID-19 cases have been reported worldwide and more than 1 million people have died of the viral infection, according to Johns Hopkins.

Cox Media Group