Even if an envelope does become contaminated and the virus is still alive when it reaches a person's home, the chances of transmission to a person's fingers are slim to none.
"We had people touch all kinds of surfaces with viruses on them, and paper was probably the least worrying of the whole group," Gerba said, referring to his past research. "There was only about 1-2% transfer of any viruses from touching the surface, whereas a stainless steel door knob or push plate, or a smooth plastic surface, is about 70%."
That's largely due to the porous nature of paper, Gerba says. Microorganisms like the novel coronavirus get trapped in paper's tiny holes and crevices, making transfer to the fingers unlikely. Smooth surfaces like metal or plastic, however, facilitate the transfer of viruses at a much higher rate.
A good rule of thumb, according to Gerba: "Generally, the easier it is to clean a surface, the easier it is to transfer something to your fingers."
Camins says that at Mount Sinai Hospital, where he works, healthcare workers sometimes express concerns about the virus lingering on patient consent forms, but the hospital has not issued a policy on the matter since paper is such a poor conduit for the virus. "Paper is fine. We just say to wipe their pens — pens are plastic — if they're really worried," Camins said.