How long do viruses like cold, flu and coronavirus survive outside the body? What factors affect this?
The editor of this page, Lilian Anekwe, writes:
Understandably, the covid-19 pandemic has many people worried about the spread of virus-laden droplets in the air. After this question was published, it was effectively answered by one of our news stories.
There is some evidence that cold and flu viruses can remain infectious for several hours, depending on where they fall. They tend to stay active longer on hard surfaces like stainless steel or plastic than on soft, porous ones like fabric. The amount of virus deposited and the level of heat, humidity and ultraviolet light can also determine how long some viruses stay active outside the body.
Different viruses seem to have differing abilities to survive outside the body, however, and we are still learning about the new coronavirus.One studysuggested it can survive for up to 72 hours on plastic and stainless steel, less than 24 hours on cardboard and less than 4 hours on copper (newscientist.com/viral-survival).
However, a report by the US Centers for Disease Control and Prevention suggested that traces of the new coronavirus could be present on surfaces for longer. This is because RNA from the virus was detected on surfaces in the cabins of the Diamond Princess cruise ship 17 days after passengers had left, including those who hadn't shown symptoms of covid-19.
Other research suggests that the related SARS and MERS coronaviruses can persist on metal, glass and plastic surfaces for up to nine days.
Virus particles expelled in coughs or sneezes may have a protective layer of mucus that helps them survive. But this may also mean that viruses lingering on surfaces can't necessarily still infect other people.
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