Coronavirus disease spread: At the start of the COVID-19 pandemic, many experts speculated that the new coronavirus was transmitted through direct or close contact with infected people who released tiny respiratory droplets when they coughed, sneezed, spoke or sang. Touching contaminated surfaces, called fomite transmission, was also considered an important way of spreading the virus.
A big question that has bothered health officials since the coronavirus passed from animals to humans in December is how exactly it is transmitted between people. There was never much doubt that, like other viruses, this virus could land on a hard surface or in the hand of an infected person, coughing or sneezing, and be caught by the hand of an infected person. another person, by a handshake or by the hand. . a twist. . of a doorknob, then smear it over your face, where it sneaks into your eyes, nose, or mouth.
What has become much less clear is whether this coronavirus, called SARS-CoV-2, is transmitted through the air and remains suspended in the air long enough, albeit doable, for someone to other puts it in your eyes. or you inhale and you are infected.
The answer seems to be yes, yes, yes and probably. If that happens, it would help explain why COVID-19, the disease caused by the SARS-CoV-2 coronavirus, is so highly transmissible.
3 hours of flight
Important evidence emerged on March 17, when researchers reported in the New England Journal of Medicine that the coronavirus can remain viable not only in droplets that tend to fall relatively quickly, but in droplets called aerosols that can float for several minutes. or hours.
They report that “SARS-CoV-2 can still survive in aerosol during our experiment (3 hours)”, which indicates that aerosol transmission is “reasonable because the virus can be in aerosol within a few hours. Stay vigorous and infectious”.
“May” and “plausible” are obviously qualifiers which do not correspond to “fact”.
Lisa Brosseau, ScD, respiratory protection and infectious disease specialist and retired professor at the University of Illinois at Chicago, is inclined to “yes”.
“This is the right time for exposure, inhalation and infection to occur near and far from a source,” writes Brosseau in a comment posted by the Center for Infectious Disease Research and Policy. University of Minnesota. It offers a look:
Have you ever used hair spray or kitchen spray? Many of these droplets stay in the air nearby when you inhale the particles and smell the hair spray and cooking oil for several minutes, ”she writes. The same thing happens when people cough or sneeze. Talking, breathing, coughing and sneezing create an aerosol (a suspension of particles in the air) that contains particles of different sizes, with viable infectious organisms present in small and large particles. “
Other scientists agree.
Lidia Morawska, an aerosol expert at the Queensland University of Technology in Australia, said in an article: “In the minds of scientists working on this subject, there is no doubt that this virus is spreading through the air. “Published by Nature. “It is clear.”
No one knew how far the coronavirus could travel or how long it could remain viable and truly infectious, especially from the aerosols created by speaking or breathing. But one thing’s for sure: you don’t want to be on the front lines of a cough or sneeze.
WHO is still not convinced
However, the science, which informs vital decisions and guidelines on physical distance if everyone should wear masks and other preventative measures in hospitals and homes, is uncertain among health officials.
The World Health Organization notes that the New England Journal of Medicine study was conducted with lab equipment, not real people coughing or sneezing. WHO says there is not enough evidence to conclude that the coronavirus can be transmitted through the air, except when someone infected with COVID-19 “coughs or exhales, producing droplets that reach the nose , someone else’s mouth or eyes “directly while the two are in close contact.
However, the United States Centers for Disease Control and Prevention recognizes that COVID-19 is transmitted “by respiratory droplets produced when an infected person coughs, sneezes or speaks”, hence the advice to stay at least 2 meters. distance from others. However, that doesn’t mention aerosols, which stay in suspension longer than drops.
The White House has been made aware of all of this.
Harvey Fineberg, chair of the Gordon and Betty Moore Foundation and committee chair, wrote: “Currently available research supports the possibility that SARS-CoV-2 may be transmitted through bioaerosols directly generated after patients breathe out.” White House information on emerging infectious diseases . . And health threats in the 21st century.