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Researchers are learning how the new coronavirus can spread. Getty Images
  • A new study has found evidence of SARS-CoV-2 (the new coronavirus that causes COVID-19) in the air around two hospitals in Wuhan, China.
  • One hospital was dedicated to treating patients with severe cases of COVID-19, while the other was a makeshift field hospital used to quarantine and treat people with mild symptoms.
  • Wearing a mask can help you avoid inhaling infected droplets and releasing them into the air if you happen to be carrying the virus.

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.

Reducing our risk for COVID-19 depends on how well we understand the way SARS-CoV-2, the virus that causes COVID-19, is transmitted.

Experts believe SARS-CoV-2 mainly spreads from person to person through respiratory droplets released when a person with the virus coughs, sneezes, or talks.

It’s also possible that you can contract the virus if your hands come in contact with your mouth, nose, or eyes after touching a contaminated surface.

But can SARS-CoV-2 be spread through the air we breathe?

A new study has found evidence of the virus in the air around two hospitals in Wuhan, China.

While it’s still unclear whether you can contract the virus from breathing virus-laden air, the latest findings could make an impact on how we protect ourselves as states begin to open up.

In a report published April 27 in the journal Nature, researchers measured the concentration of genetic material known as RNA from the new coronavirus in samples collected in February and March from 30 spots in and around two COVID-19 treatment hospitals in Wuhan.

One hospital was dedicated to treating patients with severe cases of the disease, while the other was a makeshift field hospital used to quarantine and treat people with mild symptoms.

The investigators found higher concentrations of material from the virus in samples collected in areas prone to crowding, certain intensive care units, and places with poor airflow, like bathrooms.

Areas where medical staff removed protective apparel were found to have elevated concentrations of viral material, which may indicate that SARS-CoV-2 can be resuspended in the air when staff take off their apparel.

Sites that were rigorously sanitized, well ventilated, and uncrowded were found to have low or undetectable concentrations of viral RNA in aerosol samples.

A World Health Organization scientific brief from March 29 found that there were no reports of airborne transmission of the new coronavirus.

While the recent Nature study didn’t look at whether airborne viral material can infect someone, the findings indicate the need for further research on the possibility of contracting the new coronavirus from air contaminated with viral material.

“If you think about aerosol transmission in medicine, the chickenpox can be transmitted just by someone having been in a room where someone [with the virus] was breathing before they had any symptoms,” said Dr. Natasha Lewry Beauvais of Northern Virginia Family Practice. “The typical cold virus is not transmitted that way.”

The size of the particles may make a difference in whether the virus can infect someone, says Dr. Jill Grimes, a board certified family physician and author of “The Ultimate College Student Health Handbook.”

The respiratory droplets believed to spread COVID-19 are around 5 microns, while the aerosolized SARS-CoV-2 in the study were as small as a quarter of a micron in size.

“The problem with aerosolized particles is that they’re teeny tiny. How many particles does it take to infect someone? We don’t know the answer to that,” Grimes said.

Wearing a mask can help you avoid inhaling infected droplets and releasing them into the air if you happen to be carrying the virus.

N95 respirators, which are being reserved for healthcare workers, filter particles as small as 0.1 microns.

Cotton fabric, often used for homemade cloth masks, have pore sizes between 50 and 100 microns, according to an article from Grimes.

She recommends wearing masks made from at least two layers of fabric and inserting a coffee filter between them for more protection.

“Those cloth masks need to be washed after you wear them, at least every day,” Grimes added.

Taking precautions around the known ways that the new coronavirus spreads can help keep you safe as states begin to reopen.

While it’s clear that small amounts of SARS-CoV-2 material may be in the air, doctors say the biggest risk of contracting the new coronavirus come from person-to-person transmission and, to a lesser degree, contact with contaminated surfaces or objects.

Even though the recent Nature study showed that well-ventilated areas have lower concentrations of airborne SARS-CoV-2, that doesn’t necessarily mean it’s significantly safer to dine outdoors than inside a restaurant.

“The hard science is on droplet transmission,” Beauvais said. “In a restaurant, people take off their masks to eat and drink, and people can release droplets when they laugh, sneeze, or cough — even without being sick.”

She adds that the risk of spreading and contracting the virus is on a continuum based on environment (crowded places may be more dangerous than spots where you can practice physical distancing) and people’s attentiveness to things like handwashing and wearing masks.

Just because your state is opening up doesn’t necessarily mean it’s completely safe to resume all normal activities, says Dr. Matthew Heinz, hospitalist and internist at Tucson Medical Center.

“Follow the recommendations of public health officials and qualified scientists, not politicians or social media. The folks who have helped squash Ebola and H1N1 really know this stuff,” Heinz said. “This is an insidious ninja virus that hasn’t gone anywhere. It’s still doing its job.”