A study published in the New England Journal of Medicine on March 17 found that SARS-CoV-2, the virus that causes COVID-19, could live up to 24 hours on cardboard. A study published in The Lancet on April 2 found that it could last up to three hours on paper. But keep in mind that the virus will likely break down more quickly outside of a laboratory, due to real-world exposures like sunlight, wind and temperature, experts say.
So yes, there is likely some risk that the virus could be on your mail, but it’s a small one. “A letter that’s been mailed to you and been traveling through the postal service for a couple of days, the virus will be off of that,” says Jared Baeten, professor of global health, medicine and epidemiology at the University of Washington. The risk comes when the carrier handles your mail and brings it to your door, potentially exposing it to the virus again.
The infectious dose of the virus—the amount a person has to be exposed to in order to become infected—is still unknown, says Jared Evans, a senior scientist at Johns Hopkins University Applied Physics Laboratory. So even if the virus is on a package, it might not be enough to get you sick.
Still, out of an abundance of caution, Matthew Freeman, an associate professor of environmental health, epidemiology and global health at Emory University Rollins School of Public Health, recommends opening your package or mail outside your house, disposing of the box or envelope, coming back inside and immediately washing your hands. If you want to be even more thorough, you can also wipe down the contents of a package and then wash your hands again, although it’s quite unlikely the virus will have survived. Crucially, you should make sure to stay at least 6 feet away from the mail carrier at all times.