Previously I've asked a question focused on COVID-19: Why did countries initially presume that detecting COVID-19 requires a deep nasal swab?
@Fizz provided the following response:
So clearly it was preferred for Covid-19 because of the "received wisdom" from other respiratory virus illnesses. (To pick a random example, the 2005 WHO guidlines for avian influenza don't mention saliva samples, but various kinds of swabs and washes (for the upper respiratory tract): nasal swab, nasopharyngeal swab, nasopharyngeal aspirate, nasal wash, throat swab.)
If you want to ask why saliva sampling is not a method more widely used (instead of, or, in addition to nasopharyngeal swabs) in other respiratory virus diagnostics, modify your question according (incl. tag).
So my follow up question is: how did we arrive to the "common wisdom" of using nasal swabs in respiratory virus diagnostics? Was it just presumed that it's more efficient than saliva testing or was there any research on this matter?