This article was first published in The Montreal Gazette.
In the early days of the pandemic, one of the big worries was the possibility that COVID-19 could survive and be spread by inanimate objects. This idea of fomite transmission led many to disinfect their groceries, put their mail in quarantine for three days before opening it, and worry excessively about touching any physical surface.
This fear was partly driven by early studies suggesting that the virus could survive up to 72 hours on some surfaces. Often lost in the discussion was the fact that these types of studies were done under lab conditions rather than in the real world, where sunlight, fluctuating temperatures and inhospitable weather would severely limit the virus’s ability to survive outside the human body. Unlike bacteria, viruses cannot make copies of themselves unless they infect the cells of another living thing, and so any virus particles sneezed onto a surface will eventually degrade and die.
Early on in this pandemic, no one knew how long that degradation would take or how long the virus would remain infectious. Judging prudence to be the better part of valour, most people decontaminated everything that came through their front door. And while passing an alcohol swab over your phone is not going to cause any major medical issues, some of the actions taken during those early days, like spraying antiseptic solution from a fire truck onto pedestrians or washing your fruit with bleach, were unreasonable and dangerous.
That being said, not all impulses toward greater cleanliness are misdirected. Hand-washing is an important infection-control practice, especially in hospitals where things other than COVID-19 are also in play. And cleaning high-touch surfaces like doorknobs, handles, light switches and countertops probably does have some value. Whether they are significant sources of COVID-19 infection is debatable, but they do allow the spread of many other viruses that can make you sick.
Given the confusion and the shifting public understanding of what we should be doing, the U.S. Centers for Disease Control recently released guidelines about how and when to clean your home or business. They say regular household cleaners containing soap or detergent will kill the virus and should be sufficient for most scenarios.
In other situations, for example, if someone in the household actually has COVID-19, it may be necessary to disinfect, as well as clean, high-contact surfaces. For that the CDC refers users to the U.S. Environmental Protection Agency’s List N of disinfectants for COVID-19. These products can be dangerous if used improperly. However, as long as people follow basic safety measures by wearing gloves, washing their hands and using them in a well-ventilated area, then they can be used safely.
If someone in your house actually has COVID-19, then the obvious key is to separate them from others and have them wear a mask at all times. But unless you live in a large house with multiple rooms and many bathrooms, some cross-contamination may be inevitable. In such situations, you would likely want to disinfect as well as clean common surfaces. Detailed instructions on how to handle the cleaning of bedrooms, bathrooms, dinner plates and dirty laundry are all provided, but they require no special measures beyond basic common sense.
The CDC makes a point of saying that many practices like fogging, fumigation, electrostatic spraying, ultrasonic waves, high-intensity UV radiation and LED blue light have no clear benefit and potentially carry some risk. Such excessive measures are unnecessary and regular cleaning products are more than enough. This holds true even for the variants, as there is nothing to suggest that they can survive for longer outside the human body.
But the most likely way for COVID-19 to enter your home is not on the surface of your groceries. If it enters your household, it probably got there inside of you. Clean if you must, but staying home if you can is the more useful strategy.