There have been many reports about how long the coronavirus can last on different surfaces, and still be able to cause human infections. Traces of the virus were found on the Diamond Princess Cruise ship 17 days after passengers left the ship according to a new report by the U.S. Centers for Disease Control and Prevention (CDC).
The closed setting of a cruise ship can lead to a perfect storm for a virus such as this. There are normally people from many different countries in a closed setting over an extended period, before disembarking and going home.
The recently released CDC report said RNA from the virus was found “on a variety of surfaces in cabins of both symptomatic and asymptomatic infected passengers up to 17 days after cabins were vacated” however, the ship had not been disinfected yet.
The researchers said the genetic material or RNA of the coronavirus that causes COVID-19 “was identified on a variety of surfaces in cabins of both symptomatic and asymptomatic infected passengers up to 17 days after cabins were vacated on the Diamond Princess but before disinfection procedures had been conducted,” but that doesn’t mean the virus was spread by surface.
Alon Vaisman an infection control physician from the University of Toronto describes RNA as “the basic building block of the genetic code for the virus.” He cautions that its “unlikely” this RNA would be from a live virus, as the CDC report did not specify.
“We don’t know if it’s [a] live virus or not, all that we know is that its genetic material,” said Vaisman.
The author of The Germ Code, Jason Tetro recently told Global News:
As we know, the longest a coronavirus can last on a surface is nine days in a laboratory — you can’t get it to last longer than that,” he said. “So this identification does not have any impact on [the] transmission on the risk for humans, it just simply means that at one time or another, the virus happened to be on their ship.
To help try to clarify how long this virus can last and still infect people, scientists from the National Institute of Allergy and Infectious Diseases (NIAID) attempted to mimic the spread through coughing or touching on everyday household items.
What they found was coughing or sneezing can still infect people in aerosols for at least three hours. It was still detectible on plastic for around 3 days, copper and stainless steel surfaces deactivated the virus in around 4 hours, but it was still detectible for 48 hours.
Tetro cautioned the laboratory results. “When you look at real-life situations, the virus will have an exponential decay over the first few hours, no matter what surface it happens to be on,” he said. “The real risk only occurs over the course of a half-day, and then after that, it’s not so much of a risk.”
The CDC report doesn’t change much as far as how people should take the necessary steps to try and prevent the virus. Staying home with their families and loved ones still seems like the safest bet for not getting infected.
Jason Kindrachuk is an assistant professor and Canada Research Chair in emerging viruses at the University of Manitoba who reached out to Global News via email. He said even though pieces of viral RNA can remain on surfaces for extended periods, “this does not reflect infectious virus.”
