How many people spray their shopping bags and surfaces with disinfectant after a trip to the supermarket?
How many people order takeout in terror, throwing away the packaging before they come in, disinfecting their hands and microwaving their food?
So is there a risk of infection if coVID-19 is present on surfaces?
Negligible, say the experts.
During the epidemic, Dr. Emanuel Goldman, a professor of microbiology, biochemistry and molecular genetics at Rutgers University, was forced by his mother-in-law to wipe groceries, takeout bags and wipe around with disinfecting wipes.
So Dr. Goldman wondered, “Is this really necessary?”
In the further study of the related will be coronavirus spread scientific literature, he thinks can confirm: touch virus contaminated surfaces (scientists refer to as vectors, fomites), cause infection will be the risk of coronavirus, is negligible (negligible).
Dr. Goldman is one of many researchers who now believe that coVID-19 infection through an infectious agent may be much less likely than first thought.
While they still support good hand hygiene and surface cleaning and disinfection, they believe that more important precautions are keeping body distance and wearing masks.
If they are right, that means pushing elevator buttons, touching doorknobs and sending children to outdoor playgrounds are not too risky.
“You still have to protect yourself,” Dr. Goldman said.
People should not ignore the severity of the OCIVD-19, but protect themselves correctly: don’t worry about the surface, worry about your breath.”
Earlier this month, Dr. Goldman published a commentary in the Lancet titled “The Risk of Vector-borne TRANSMISSION of COVID-19 is Exaggerated.”
In his comments, he noted that research hypotheses about surface infection do not reflect real-life situations.
Figure: The Lancet
For example, novel Coronavirus has been shown in several studies to survive on an object surface for several days.
But in these studies, researchers used a number of orders of magnitude more virus particles than people would normally encounter.
Some studies have used between 1m and 10m infectious virus particles in each sample.
This is equivalent to collecting respiratory droplets from 10,000 to 100,000 infected people and spraying them all over a small area.
“This is ridiculous,” Dr. Goldman said.
I have no problem with the quality of the research, but it has nothing to do with the real world.”
Novel coronavirus will have a much shorter life span in studies using a small number of virus particles.
In one study, the Novel Coronavirus particles lived only one to three hours, he said.
He also found another study that better reflects the number of viruses people typically encounter.
The study showed that after only about an hour, no infectious virus particles were found.
There’s another problem with this kind of research.
Dr. Gerald Evans, director of the Department of Infectious Diseases at Queen’s University, said many studies look for so-called viral RNA or viral nucleic acid, but that does not mean there must be an actual live virus — a virus that can cause infection.
“RNA is a sticky molecule, and when it sticks to a surface, it’s hard to get rid of it,” Dr. Evans says.
Physically, it’s like a sticky substance.”
The test used by many researchers, like the one used to identify COVID-19, first stores viral RNA and amplifies the target so it can be detected.
However, these tests cannot determine whether there is a live virus or not.
To be sure, Dr. Evans explains, researchers need to collect samples from an area and put them in a cell culture.
If a live virus is present, it will infect cells in the culture;
If only viral RNA is present, it does not infect cells.
Chinese researchers have conducted environmental studies in hospitals and public places, he added.
They can only find live viruses in highly contaminated areas, such as hospital toilets and changing rooms.
Because in these places, medical workers need to take off their PERSONAL protective equipment.
The risk of surface exposure to COVID-19 depends not only on the presence of live virus, but also on how much virus accumulates in the area.
People tend to expel large amounts of virus particles from their airways within a day or two of symptoms, Dr. Evans said.
For those with mild illness, infective particles are no longer shed after eight or nine days, and the number is almost zero.
In addition, the surface propagation of an object is affected by many other variables, including the material of the object.
Novel Coronavirus will not survive ona hard, nonporous material, such as stainless steel, Dr. Evans said.
The virus is more likely to be covered by respiratory secretions in the palm of your hand than in the exposed environment.
High temperature and humidity seem to reduce the infective potency of novel Coronavirus, Dr. Evans adds, but the relationship is not always clear.
In addition, ultraviolet light from the sun may inactivate the virus, so outdoor playground equipment may not be as dangerous.
Having said all that, however, Dr. Evans thinks it is still worth the effort to clean and disinfect.
“But the biggest problem with prevention is that we haven’t addressed the main route of transmission — respiratory droplet transmission.”
Dr. Samira Mubareka, a virologist and infectious disease specialist at Sunnybrook Health Science Centre in Toronto, said she had a similar view of the limited transmission discussed by Dr. Goldman in the Lancet.
However, she still does not personally recommend that children be allowed to play in the playground.
In nursing homes with large Numbers of confirmed cases, she said, it is difficult to determine whether the virus spreads by touching surfaces or by sharing breathing areas.
“It’s hard to separate the two, they happen together.”
Dr. Mubareka added that there are many variables that can affect surface transmission, including individual behavior, such as whether children touch a surface with the virus after touching it.
The risk, therefore, depends.
“It’s not black and white.
“Many of the people who have been diagnosed, after they’ve brought the virus home, start to think about what they’ve been exposed to.”
After the news came out, some Canadian netizens said that they did not believe the scientists’ words at all.
Willy96: In 150 days, so called science has gone from “just wash hands, no masks” to “breathe carefully, wear masks”.
Politicians talk of low risk while shutting down the economy to dole out billions.
Either these politicians and scientists are village idiots, or I have to become a believer in conspiracy theories.
I’m going to look at the old farmer’s almanac and horoscopes and plan my life for the rest of my life.
Bob.McK: The story of Dr. Goldman tells us that no one is an expert when it comes to mom.
However, some netizens support the idea that outdoor amusement parks should be open, as long as the number of people using them is limited.