There’s no doubt that mask-wearing and sanitizing are both important for stopping the spread of COVID. But two years later, most people have stopped wiping surfaces down as often as before. But new research may have you wanting to order disinfectant wipes in bulk once again. According to scientists who performed tests for the Food Standards Agency (FSA), the COVID virus can stay on some grocery surfaces for days. For the study, scientists purposely put the COVID virus on food packaging for drinks, pastries, fruit, canned goods, drink cartons and other items. After 24 hours, they found a significant drop in the COVID particles on the packaging. However, they did continue to find traces of the virus on certain surfaces several days later. How worrisome are these findings? Here, three infectious disease doctors give their thoughts.
How COVID Can Be Spread Through Surfaces
First, a little COVID-spreading-101 as far as surfaces are concerned. After all, it might have been a couple of years since you thought about the virus in this way. “COVID is spread once its viral particles reach the surface. If they survive long enough and come into contact with your hands or mouth, they are ultimately transferred to your mucosa, covering inside the mouth, where they then infect your body,” explains Dr. Roger Seheult, MD, a medical advisor to On/Go COVID rapid test producer Intrivo, an associate clinical professor at the University of California, Riverside School of Medicine, and an assistant clinical professor at the School of Medicine and Allied Health at Loma Linda University. “SARS-CoV-2, the virus that causes COVID, can be spread by touching a surface that has been contaminated with the virus and then touching the mouth, nose or eyes,” says Dr. Meghan Baker, MD, ScD, an assistant professor in the Department of Population Medicine at Harvard Medical School. Here’s what this could look like, hypothetically speaking: Someone with COVID may cover their mouth while coughing and then use their hands to sort through some oranges at the grocery store, selecting some to take home. Later, someone else comes along and touches the same oranges they did. Then, they absent-mindedly bite their nails while waiting in line at checkout. If they picked up COVID particles from the oranges, putting their fingers in their mouth could potentially lead to getting the virus. Dr. Seheult says that contracting the COVID virus from a surface requires the spike protein (which latch onto receptors on target cells) and other proteins on the surface of the virus to remain intact and functional—something that can break down rapidly depending on the nature of the surface and the time it has spent on there. This is why the researchers found that the COVID particles on surfaces drastically reduced after 24 hours.
How Worried Should We Be About Getting COVID by Touching Surfaces?
While the new study may be alarming, infectious disease doctors say it’s not something we should be overly concerned about. “COVID is not primarily spread through surfaces,” Dr. Baker says. “The majority of transmission is by inhalation of respiratory aerosols.” (For example, if you have a conversation with someone with COVID and the particles travel from their mouth through the air into your own mouth.) Dr. Monica Gandhi, MD, MPH, the associate division chief in the Division of HIV, Infectious Diseases, and Global Medicine at UCSF/San Francisco General Hospital, also says that COVID is not primarily spread through surfaces. “We do not think COVID is spread by touching surfaces, despite this new report where researchers actually inoculated food or food packages with live SARS-CoV-2 virus and then cultured and recovered virus from those inoculated surfaces,” she says. “The report describes an artificial situation in which researchers smeared surfaces with virus; that is not likely to occur in real life and under the conditions of a typical grocery store visit.” Dr. Gandhi points to past research showing that transmission of the virus through indirect contact (like touching a surface that someone with COVID previously touched) is unlikely. For example, in one study, researchers swabbed the surfaces in hospitals that patients who tested positive for COVID touched. The swabs did not pick up any particles of the virus. Other studies had similar results. “Many routine disinfection rituals, including the ubiquitous usage of alcohol-based hand sanitizers and the excessive use of strong cleaning products, are unnecessary,” Dr. Gandhi says. In fact, Dr. Gandhi says there are times when overly sanitizing can be dangerous. For example, someone may wash their food products in bleach or household cleaning products in an effort to protect themselves from COVID and could end up consuming harmful particles from these cleaning agents later while eating the food. “Based on previous data, experts believe that it takes about one thousand viral particles to successfully cause an infection,” Dr. Seheult says, also speaking to the unlikelihood of getting COVID through surfaces. “As the number of particles transfer to a surface, it is possible that some may be viable enough to infect a person, but it becomes less likely when there are less than a thousand particles ultimately transmitted. Your body has defense mechanisms that can rapidly shut down an infection, so for the virus to successfully cause an infection it must overwhelm that initial step.” Instead of obsessing over the lifespan of COVID on surfaces, the doctors say what would be more helpful is to be diligent about getting vaccinated and boosted. Wearing a mask and regularly using hand sanitizer can also help prevent sickness, not just from COVID but from other illnesses making their rounds this winter. “Focus on hand hygiene and not touching your eyes, nose or mouth,” Baker says. “I would prioritize wiping down high touch surfaces and surfaces in areas with a higher density of individuals at high risk of severe disease, to help protect those individuals from getting infected.” If you put all of this into practice, you are truly doing what you can to best protect yourself and others. Next up, find out how COVID boosters and vaccines could be different in the future than they are now.
Sources
Dr. Roger Seheult, MD, medical advisor to On/Go COVID rapid test producer Intrivo, associate clinical professor at the University of California, Riverside School of Medicine, and assistant clinical professor at the School of Medicine and Allied Health at Loma Linda University Dr. Meghan Baker, MD, ScD, assistant professor in the Department of Population Medicine at Harvard Medical SchoolDr. Monica Gandhi, MD, MPH, associate division chief in the Division of HIV, Infectious Diseases, and Global Medicine at UCSF/San Francisco General Hospital
