I think I read somewhere that the virus has a half-life of roughly 6-7 hours on cardboard. I've also read "24 hours" as a guideline for how long the virus can last. Apparently it depends on conditions such as temperature, sunlight, and humidity. (In particular, direct sunlight and warm weather apparently cause the virus to die faster.)

Although I'm not an epidemiologist, I suspect that your probability of catching the disease from a package decays roughly exponentially with time.

Personally, and as someone not immunocompromised, I've been setting my packages aside (in my apartment) and washing my hands thoroughly afterwards. In cases where I'm particularly eager to get the contents, I'll open them after a day and not worry too much. Otherwise, I'll let them sit for two or three days.

Bleach and peroxide, among other disinfectants, do kill the virus. One could clean the outside of the box before opening it.

Not sure why parent is subtracting the transit time: Who delivered the package? Were they infected? Exactly.

Assuming you’re referring to my comment:

> wait another day or so for the exterior surface to become safe.

Unless you think that for some reason the exterior of the box is going to have live virus for more than what’s been reported, this seems reasonable.