Most of us stopped wiping down our groceries and disinfecting all our possessions much earlier in the pandemic when we learned the real risk of COVID-19 transmission was in the air. Does the arrival of the omicron variant change that calculus?
According to the Centers for Disease Control and Prevention, respiratory transmission is still the primary concern. “It is possible for people to be infected through contact with contaminated surfaces or objects (fomites), but the risk is generally considered to be low,” the agency says.
“I have no reason to expect that omicron will act any differently (than other variants) with risk of transmission via surfaces,” said Dr. Peter Chin-Hong, an infectious disease specialist at the University of California, San Francisco.
How long can the virus last on surfaces? If the surface is porous, like cotton, for example, “Studies report inability to detect viable virus within minutes to hours,” says the CDC. If the surface isn’t porous, like glass, stainless steel or plastic, studies have been able to detect the virus after days or weeks.
However, under “typical indoor environmental conditions,” studies have found a 99% reduction in infectious coronavirus in three days or 72 hours. That timeline speeds up by a lot when you factor in ventilation, like an open window.
Disinfectant solutions have been proven to work against the virus, as well, but experts don’t believe that cleaning should be the main focus. The risk of fomite transmission (getting sick from a surface that has virus particles on it) is very low, the CDC says, and the risk of respiratory transmission (getting sick from breathing in virus particles) is quite high — especially in indoor environments where people aren’t wearing masks.
“I have never cleaned my groceries at any time in the pandemic before … and I don’t expect to — ever — during COVID surges,” said Chin-Hong. “The air is the issue and we should be laser-focused on that rather than be distracted with surfaces.”
Can the virus survive in the air even after an infected person has left a room? Research suggests the answer is yes: Particles can linger for anywhere from minutes to hours, the CDC says. It all depends on the air flow in the room, the temperature, humidity and other factors.
“I don’t get nervous, when I go into a room, about who’s been in the room before me,” said Dr. Kirsten Bibbins-Domingo, chair of UCSF’s epidemiology and biostatistics department in an interview with CapRadio. “But I do get nervous anytime I’m inside a room that’s not that well ventilated, about even people who are across the room, or people who might be much further from me than I would generally think about. Because the air that’s there is just not circulating in the way that is really designed to keep me safe. Those viral particles are sort of hanging in the air.”