For how long can influenza survive on a piece of paper?
Perhaps just eight to 12 hours.


  Both influenza A and B viruses survived for 24-48 hr on hard, nonporous surfaces such as stainless steel and plastic but survived for less than 8-12 hr on cloth, paper, and tissues. Measurable quantities of influenza A virus were transferred from stainless steel surfaces to hands for 24 hr and from tissues to hands for up to 15 min.


--Survival of influenza viruses on environmental surfaces.

Or, perhaps, up to 17 days, when in the presence of "respiratory mucus" (i.e. snot), although even then a couple days was more plausible. Note that this was on Swiss banknotes, which isn't standard paper.


  Influenza A viruses tested by cell culture survived up to 3 days when they were inoculated at high concentrations. The same inoculum in the presence of respiratory mucus showed a striking increase in survival time (up to 17 days)....  When nasopharyngeal secretions of naturally infected children were used, influenza virus survived for at least 48 h in one-third of the cases.


-- Survival of influenza virus on banknotes.