How important in transmitting infection are the Sars-CoV-2 viruses found on surfaces? What a difference a year makes, in so many ways! A recent Dec. 28, 2020 article from NPR news service was entitled “Still Disinfecting Surfaces? It Might Not Be Worth It.” Huh? We’ve had a lot of experience with the infection, have learned a lot, and are still learning.
When the pandemic began, nobody knew what source of transmission was important. Every possible route had to be considered, especially touching contaminated surfaces and putting hands in mouths, up noses and in eyes. We were told to wipe down light switches, and sterilize groceries from the store. Cleaning supplies were hoarded. From a San Francisco Chronicle paper Sept. 28, 2020, article, infectious disease specialist and researcher Monica Gandhi, who has written extensively about this virus, was quoted saying, “The surface issue has essentially gone away.” She was implying that the sheer manic paranoia about not touching anything when you are out has lessened.
From NPR, Rutgers University microbiologist Emmanuel Goldman says, “In hospitals surfaces have been tested near COVID-19 patients, and no infectious virus can be identified. What is found is viral RNA, the genetic material, which is like ‘the corpse of the virus.’ That’s what is left over after the virus dies. They don’t find infectious virus because the virus is very fragile in the environment and decays quickly.” To attach to and invade a human cell, a complete, infectious virus has to have its protein outer layer or coat, which, for this virus, is its infamous “spike” protein.
Checking references from these two articles, Harvard, Cleveland Clinic in Ohio, U. of California at Davis, the National Academies of Science, etc., they now express a consensus that breathing in the virus from the air from the droplets or aerosols is by far the major route the viruses take to infect us. Early surface studies were done in pristine lab conditions using much larger amounts of virus than would be found in real life settings.
How long cans the virus last on surfaces? According to studies from the New England Journal of Medicine and the British journal Lancet: Aluminum (foil, window frames, ladders, etc.), 2-8 hours; paper (mail, tissues, toilet paper, magazines, newspapers, etc.), 3 hours; copper (coins, jewelry, wires, etc.), 4 hours; cardboard (shipping boxes, food packaging, etc.), 24 hours; cloth (bags, bedding, blankets, carpet, hair bands, etc.), 2 days; wood (furniture, tabletops, etc.), 4 days; plastic (light switches, credit cards, food packaging, ATM buttons, etc.), 7 days; metal (utensils, keys, pots and pans, door handles, etc.), 5 days; glass (glasses, stemware, windows, mirror, etc.) 5 days; paper money, 4 days (It doesn’t last that long in my hands); and face masks (type not specified), 7 days. It’s not known if viruses on surfaces retain their infectivity.
These numbers were obtained from lab studies. There is not enough clear evidence to suggest how the virus behaves — or misbehaves — under real life conditions, such as exposure to direct sunlight, extreme heat, or cold. It may be possible that a person can get the virus by touching a surface or object with the virus on it, but now it is not believed to be the primary route of infection.
An atmospheric chemist from Colorado State University, Delphine Farmer, has said, “spraying disinfectants is not only not productive, but potentially dangerous.” Heavy use of disinfectants like bleach and hydrogen peroxide can produce toxic molecules that we breathe. Early in the pandemic many people were making cleaning mistakes. There were a lot of cases of people cleaning their groceries with bleach and vinegar, which is a recipe to create some very nasty chlorine gas, and people were getting ill from these side effects.
The essence here to be aware of surfaces you touch, and wash your hands often, which is more effective than trying to clean everything you touch. Soap will break up the protein capsule of the virus. Hand washing works for SO many other contagions a well. The possibility of getting infected via this route still exists, but not to the degree originally suspected. Mom was right. Wash your hands.
To repeat, what a difference a year makes! Last year my resolution was to lose 10 pounds. This New Year I realized I only have 15 to go.