CDC changes its 'confusing' guidelines on coronavirus and surfaces. Here's what we know.

Recent guidance issued by the U.S. Centers for Disease Control and Prevention should have clarified how coronavirus spreads through surfaces.

But two days after the federal health agency's guidelines said COVID-19 "does not spread easily" on surfaces, a clarification was issued, explaining that the wording used was "confusing."

"This change was intended to make it easier to read, and was not a result of any new science," the CDC said in a news release.

Though the coronavirus could be transmitted by touching a surface – and then your nose, mouth or eyes – the likelihood of that is lower than person-to-person contact, which is believed to be the primary way the coronavirus is transmitted.

"This is not thought to be the main way the virus spreads, but we are still learning more about how this virus spreads," the CDC's recently updated guidelines say.

Dr. Manisha Juthani, an infectious disease doctor and associate professor of medicine at Yale University, told USA TODAY that the newly issued guidelines were "trying to reduce fear and paranoia about methods of transmission."

From virus shelf life to susceptibility: What we know about the coronavirus keeps changing

More important, she says, is that "people MUST continue to maintain physical distance, wash hands and try to avoid touching your face." She also advises wearing masks, especially in crowded places.

"These habits will help going into the respiratory virus season this fall and winter."

This update may quell some major concerns about how COVID-19 is transmitted, but there are still plenty of questions lingering. Here's what we know.

This is what we thought we knew about coronavirus on surfaces.

Most respiratory diseases, including COVID-19, do tend to last on surfaces, Juthani said.

Two major findings published within weeks of each were crucial in shaping what we thought we knew about coronavirus on surfaces.

A study published in the New England Journal of Medicine found that viable coronavirus could live on some surfaces, such as plastic and stainless steel, for three days and surviver up to 24 hours on cardboard.

Two weeks after the finding, a CDC report said RNA, or genetic material, from the novel coronavirus was found on surfaces in the Diamond Princess cruise ship 17 days after passengers left their cabins. Genetic material does not necessarily mean that the coronavirus itself lingered.

Neither of these studies confirmed whether the coronavirus spread easily on surfaces. In fact, Joseph Vinetz, a professor of medicine at Yale and infectious disease researcher, said in March that the CDC report "has zero relevance to the ongoing epidemic."

Out of caution, however, frequently cleaning surfaces and washing hands became the norm whenever discussing the coronavirus on surfaces.

How long does the coronavirus live on surfaces?

Generally, the harder the surface, the longer the life of the coronavirus.

The virus can survive on glass for up to 96 hours, according to a study by the Journal of Hospital Infection published in January.

As stated earlier, coronavirus can last on plastic and stainless steel for 72 hours or three days, on cardboard for one day and on copper surfaces for four hours.

A visual guide: How long does the coronavirus live on surfaces?

Juthani notes that a person getting infected with COVID-19 by touching a surface requires "the outer shell of the virus" to remain intact, which remains difficult with proper hand-washing and surface cleaning.

"If surfaces are cleaned or even if you touch a contaminated surface but then wash your hands properly, the low risk of transmission from a contaminated surface becomes even lower-risk," Juthani told USA TODAY.

If I touch an area infected with coronavirus, will I get it?

Transmission through surfaces is much less likely than other forms of contact, the primary mode being person-to-person contact in an enclosed space for a long period of time, Juthani notes.

"If you wash your hands several times a day, particularly after handling objects that others could have touched, the risk of transmission is significantly lower from an already lower risk of transmission event," she said.

The CDC points out that while chances aren't high, the risk is still there.

Should I still be washing my hands after getting my packages or mail?

Yes.

The CDC has said the likelihood of getting the coronavirus from your packages is highly unlikely "because of poor survivability of these coronaviruses on surfaces."

Still, Juthani cautions that proper hand-washing is essential to preventing the spread of COVID-19.

"Although I want people to be less fearful and paranoid about surfaces," she said, "this doesn’t change the need to wash hands after touching things, especially that have been outside of your household."

Contributing: Jessica Flores, Doug Stanglin, Javier Zarracina and Adrianna Rodriguez, USA TODAY. Follow Joshua Bote on Twitter: @joshua_bote

This article originally appeared on USA TODAY: Coronavirus news: What CDC is now saying about COVID-19 on surfaces