In today’s world, figuring out how to avoid viral infections is obviously important business. The news is full of advice on the subject.
Much of it is poorly informed or wrong.
There are important measures you should take to dodge viruses – and I’ll explain those in a moment – but there’s also a worrisome side to the medical research on how viruses are transmitted from person to person.
The problem? There isn’t much research.
Few studies have actually been conducted to determine how we pick up these infections. Not to beat around the bush, this means much of what you’re told is conjecture.
Why is there so little hard evidence? I suspect that the question of how a person catches a cold wasn’t very sexy. And I’m also not sure how such an experiment would be designed. Would you recruit volunteers to be exposed to a cold or flu virus and try different things to see what made them sick? I don’t know.
Enter the “Experts”
When coronavirus came along and there was a sudden need to know, I think it suited doctors to act as though they know more than they actually do. Thus we’re now drowning in advice from “experts” who sound very sure of themselves. Having looked into the studies, my general impression is they know just about nothing.
In view of the fact that the disease can be deadly, the advice they’ve given has been extremely cautious, without giving a thought to whether it’s really possible to avoid all contact with other human beings and to touch nothing another human being has touched — potentially (according to some extremists) for as long as 18 months.
For a disease that is deadly and contagious, the medical profession’s default mode is to put infected people in total isolation and trace everyone the infected person has had contact with and isolate them as well.
I don’t have any argument with that – it’s standard operating procedure — but as we now know, it becomes fiendishly complicated when you don’t know who is infected, they may show no symptoms, we’re not very sure of how the disease spreads from one person to another, and it takes as long as two weeks to notice symptoms, assuming you ever do.
These uncertainties have given rise to a climate of fear. Since we don’t really know who might have COVID-19 or how a person is likely to get it, people assume the microbes are everywhere, all the time.
This isn’t smallpox or chickenpox, where it’s obvious when you’re sick and obvious when you’ve gotten over it.
Here’s what my team has been able to find out by actually digging into published investigations, as opposed to listening to someone with the cherished “MD” initials sound off on the tube. . .
According to researcher Lydia Bourouiba, who directs the Fluid Dynamics of Disease Transmission Laboratory at MIT, we barely know more about the spread of viruses than we did in the 1800s when Louis Pasteur first studied how microbes can make us sick.
“In the past century or so there’s still one aspect of infectious diseases which we still don’t understand much better than when Pasteur was alive – and that is the mechanism of transmission,” says Dr. Bourouiba. “Particularly when the pathogens are transmitted by breathing, coughing, sneezing, talking or even singing.”
And she adds, “When it comes down to airborne disease transmission there are so many unanswered questions.”1
But let’s take a look at what we do know.
Much of Dr. Bourouiba’s research has focused on what happens when an infected person sneezes and the viruses released in a sneeze spread. Her studies have found that it’s a surprisingly complicated business.
In her high-speed videos, it’s evident that a sneeze launches a cloud of fluid that forms a wavering balloon-like temporary structure that splits apart into long unstable extended filaments. The filaments then scatter as a spray of droplets – droplets that resemble paint being thrown through the air.2
The complicated structure of the fluid shown in the videos reveals that sneezes don’t yield a uniform droplet spray.
And every one of us apparently has an individual sneeze pattern. People with more “elastic” saliva expel fluids that retain their filament shape longer – giving off beads that form along filaments and then slide off in the form of droplets.
“What we saw was surprising in many ways,” Dr. Bourouiba says. “We expected to see droplets coming out fully formed from the respiratory tract. It turns out that’s not the case at all.”
A sneeze’s “multiphase turbulent puff cloud” means that droplets containing viruses can fill an entire room, float up to the ceiling (the warm air from a sneeze rises) and enter a ventilation system where they may spread throughout a building.
Coming Down to Earth
If no one inhales those droplets and infected droplets land on a surface such as a table, desk, door handle, floor, counter or keyboard, they can be picked up by people who touch those surfaces. While thorough hand-washing (20 to 30 seconds with soap, they say) can eliminate the viruses, if you touch your face before washing, the virus can enter your body through your eyes, nose or mouth.
Researchers have also investigated how long viruses can survive on the surfaces that surround us and remain infectious. In general, hard surfaces like plastic, glass or steel help viruses keep from drying out and enable them to survive for a day or more.3 (In theory, they can persist for up to nine days.)
However, the microbe’s infective ability diminishes greatly in a matter of hours. Porous surfaces, like fabrics, dry them out more quickly, and the drying process destroys the virus. A study of the transmission of a flu virus landing on a tissue found that it could only persist for about 15 minutes.4
So there you are – viruses live on a cold surface for something between 15 minutes and nine days. Not very helpful.
What’s Your Risk Tolerance?
Call me a wild gambler, but I don’t think you need to worry much about catching a cold or flu from a surface that was touched by an infected person more than a day ago. And unlike the “experts” on television, I’ll admit that’s just my guess. Nothing very scientific about it except for the anecdotal evidence that I rarely get a cold myself.
The danger of such surfaces can be largely diffused by washing your hands before eating or touching your face. I’m also influenced by probabilities. An elevator button or a door handle gets touched a lot. Those self-checkout touchpads in stores have been touched a lot.
A cereal box in the supermarket may not have been touched at all – or you can use your head and take the one in the back of the shelf instead of the one sitting in front.
On the other hand, I see people in the produce section handling every single piece of fruit before they decide on “their” orange or potato or whatever. So I let my groceries sit for a day once I get them home. I wash off the produce before eating it (which I always did anyway, before this pandemic.) And of course, I wash my hands after getting back from the store.
My view of the whole “cold surfaces” theory of how you catch a virus is that it’s a pretty low risk and it’s pretty easy to protect against it. Most “experts” think the most likely way to catch a virus is from person-to-person transmission. You may pick it up from shaking hands with an infected person or from more intimate contact.
You may inhale the viruses left hanging in the air from the exhalations, coughs or sneezes of an infected person.
Here again, those infernal “experts” really don’t know much. The recommendation to stay six feet apart is somewhat arbitrary. It sounds like plenty of distance to me, although just this morning I heard a talking head on television say he’d seen something that said the microbes could cross as much as ten feet. He didn’t cite a source. I guess getting infected by someone ten feet away is possible if the other person unleashes a powerful sneeze, but it seems like a stretch.
What we do know is that people are more likely to catch viruses in cramped, crowded spaces (airplanes and cruise ships, anyone?) While this pandemic is going on, you really don’t want to be packed into a room cheek by jowl with a large number of people. I think it’s safe with a small number of people amply spread out – six feet apart.
Practical Tips — Some Old, Some New
Here are some tips about reducing your chance of infection –
Get more sleep: Research at the University of California San Francisco shows that people who sleep six hours a night or less are four times more likely to catch a cold when exposed to a virus, compared to those who spend more than seven hours a night asleep.5
Avoid young children if you can: This doesn’t sound like a nice thing to say, but alas it’s true. So with the coronavirus pandemic, people in high-risk categories need to heed this advice. A study at the University of Rochester shows that when older adults interact more with school-age children they increase their risk of catching colds and suffering more severe symptoms from viral illness. Says researcher Ann Falsey, “We all know that children are efficient germ-spreading vectors and we know that young children oftentimes don’t have ideal hygiene habits. It’s not unusual for them to accidentally sneeze in your face, for instance.”6
Wash your hands frequently and don’t touch your face: The idea that hand washing prevents the spread infections was first introduced to mainstream medicine in 1847. It was true then, even though most doctors pooh-poohed it at the time – and it’s still true now.7
Open windows to increase ventilation: Dr. Bourouiba says that being outside and opening windows can help disperse infectious droplets. “When one is outside, with air circulation or wind, the cloud and its payload is easily dispersed and less concentrated. Making sure that indoor spaces are aired frequently also reduces the concentration.”8
Wear a mask when you’re near other people: The question of how much good masks do in stopping the spread of a viral infection is controversial. Some experts believe that if infected people wear masks it’s more helpful in containing the spread than when the uninfected wear them. If you wear a mask, wash it after each use. Don’t touch the surface of the mask with your hands or your hands may pick up infectious viruses. At the present time, the Centers for Disease Control and Prevention (CDC) recommend that everyone wear masks to try to contain COVID-19. But if you’re outside, by yourself, walking, running, walking a dog, etc., a mask is probably not necessary. I see people walking alone on a big street on a sunny day with blue skies. . .wearing a mask. There is no need for that. Yet in some cities people will actually yell at you if you don’t.
Generally virus epidemics die back when the weather is warm. The reason, one of my crack researchers learned, is that humid air slows down the spread of viruses because the humidity makes it easier for the lungs to defend themselves. Dry air in the winter makes mucus less protective. Dry air in an airplane also makes the lungs more vulnerable.
“Cold air can disrupt the moisture layer that lines the lower airways in the lungs by causing it to evaporate faster than it can be replaced,” says Dr. Craig Jones, an ear, nose, and throat specialist with Harvard-affiliated Massachusetts Eye and Ear. Check it out at https://www.health.harvard.edu/staying-healthy/7-strategies-to-fight-winter-breathing-problems.
This suggests to me that humidifying your space during cold weather may go a long way toward protecting you. I’ve done this religiously for years anyway, because my nose, throat and other air passages feel so much better. I literally get a nosebleed if I don’t.
Like everything else about this illness, there’s disagreement as to whether summer temperatures will put a dent in the spread of COVID-19. We don’t know yet…but I think it’s likely. So for a few months at least we may be able to lighten up on our fears.
Hopefully, the COVID-19 pandemic will inspire more studies into how infectious viral diseases spread and how to stop them. As Dr. Bourouiba warns – “We live with airborne disease transmission everyday but we don’t understand it.”9