Most health professionals rely upon the CDC for scientific guidance when it comes to preventing the spread of the coronavirus. For months, this public health organization has been telling the public and healthcare workers that the virus is spread: “Between people who are in close contact with one another (within about 6 feet).” The public health experts at the CDC emphasize that “respiratory droplets” are the culprits. We suspect that this advice from the CDC may not be scientific. We also think it may not be tough enough.
Is 12 Feet Safer than 6 Feet When it Comes to COVID-19?
The coronavirus may travel farther and more stealthily than most people think. That’s the conclusion of a small Chinese study carried out in the Huoshenshan hospital in Wuhan, China (Emerging Infectious Diseases, early release, July, 2020).
Between February 19th and March 2nd, scientists collected swab samples from potentially contaminated objects in the ICU and general ward (GW). There were 15 very sick patients in the ICU and 24 patients with milder disease in the general ward.
The investigators “sampled indoor air and the air outlets to detect aerosol exposure.” Let’s hit the pause button for a minute to let that sink in.
Droplets vs. Aerosols: What IS the Difference?
If you go back to our first paragraph you will note that the CDC mentions “respiratory droplets.” These occur when someone sneezes or coughs.
The CDC goes on to state that:
“These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs.”
Droplets are, relatively speaking, larger than aerosols. This is not a precise science, dear reader. There are large droplets and small droplets. The larger ones probably do fall to the floor within 3 to 6 feet. The smaller droplets or aerosol particles can stay suspended in air for substantially farther.
Dr. Justin Morgenstern is an emergency physician. He publishes a blog called First10EM.
In his article, “Aerosols, Droplets, and Airborne Spread: Everything you could possibly want to know,” he points out:
“Aerosols are so small that buoyant forces overcome gravity, allowing them to stay suspended in the air for long periods, or they evaporate before they hit the floor, leaving the solid particulate (‘droplet nuclei’) free to float very long distances, causing what we often refer to as ‘airborne’ transmission.”
Aerosol Spread in China:
Let’s resume where we left off with the Chinese study in a Wuhan hospital. The investigators found that the COVID-19 virus was widely distributed both in the air and on objects in the ICU and the general ward (GW). They concluded that the transmission distance was as great as 4 m (meters) or 12 feet.
These researchers found “virus-laden aerosols” in the wards of the hospital as well as near the air outlets.
They conclude:
“…SARS-CoV-2 was widely distributed in the air and on object surfaces in both the ICU and GW, implying a potentially high infection risk for medical staff and other close contacts…the SARS-CoV-2 aerosol distribution characteristics in the GW indicate that the transmission distance of SARS-CoV-2 might be 4 m.”
6 feet of Separation Not Enough for Shoes!
The Chinese researchers discovered something else the CDC has not warned about. They found that the coronavirus could be tracked all over the floor. For example, the hospital pharmacy floor tested 100% positivity even though no patients went there.
The authors note that:
“half of the samples from the soles of the ICU medical staff shoes tested positive.”
They recommend that health personnel disinfect their shoe soles before leaving the hospital.
Home Isolation No Guarantee:
The Chinese investigators warn that people suspected of having COVID-19 should probably not be quarantined at home. That’s because family members don’t have adequate training or protective gear to handle SARS-CoV-2.
We recently learned that Chris Cuomo’s wife Cristina has been diagnosed with COVID-19. That was two weeks after the CNN anchor was quarantined to his basement with the infection. This suggests that when one member of a family comes down with the coronavirus, others in the family are likely to follow.
6 Feet of Distance Did Not Work in Nebraska:
The Chinese research confirms the findings of an earlier study from the University of Nebraska (MedRxiv, preprint, March 26, 2020).
Researchers collected air samples from the Nebraska Biocontainment Unit. This early SARS-CoV-2 study found virus particles in the air in these negative pressure patient rooms. Moreover, the scientists detected viral RNA in the hallway air outside the rooms, even though negative pressure is supposed to keep virus from escaping.
Ventilation grates, toilets, window ledges and other surfaces had detectable virus. The floors under the beds and the floors in the hallways also yielded viral particles.
This suggests that people moving in and out of rooms where patients are isolated with COVID-19 should protect their shoes with disposable booties just as they protect their faces with masks and their hands with disposable gloves. You can read more details about the University of Nebraska study at this link.
Is 6 Feet of Distance Safe Outside of Hospitals?
Both the study in Wuhan and the study in Nebraska were conducted on hospitalized patients with confirmed coronavirus infections. Are there any lessons for people outside of hospitals?
The CDC has continued to recommend staying 6 feet apart. That is supposed to be safe. But these studies suggest that viral particles can travel farther with the help of air currents or shoes.
The People’s Pharmacy Perspective:
Scientists do not know how many Americans have the virus but experience no symptoms. The CDC reports that 25% of COVID-19 positive patients may be asymptomatic. Dr. Anthony Fauci says that 25% to 50% of those who catch the coronavirus show no symptoms.
Many of these people may spread the virus even if they feel fine. If they can do that by breathing, talking, touching and walking, overcoming this pandemic could take time.
We do not yet have proof positive that 6 feet is the magic distance to protect yourself from COVID-19. It could be months before we know for sure that the CDC is right. In the meantime, we suggest erring on the side of caution. If you can get 12 feet away from others, so much the better. And please wear a face covering when you are out and about.
What Do You Think?
Do you trust the CDC’s recommendation of maintaining 6 feet of distance? What’s your take on the aerosol vs. droplet question? Please share your thoughts in the comment section below.
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