I've tried to follow this very interesting thread which is very stimulating and will catch up.
'Information' is, with 'data' the paradigm of our time compounded by technology in its social effects.
Perhaps, reading on ignorance / Agnotology may also be useful here? -
I wonder if a definition of 'infodemic' should consider not just the recipient of info in these terms but the sender?
If the sender - social media corporations, a government not upholding human rights (subversive groups) 'knows' the state of ignorance - population profiling ... then messages can (and are) targetted.
(Consider the genocide in Rwanda and use of radio there.)
Looking at information in a mechanistic info-centric way as per Shannon and Weaver can be useful as a foundation:
The volume of information adds to the noise, without literacy as a filter.
There is a need then as per your focus to look beyond the individual - interpersonal context to mass communication.
This is a topic I would like to revisit as in the 21st Century we do need to consider ignorance as a concept and Agnotology as a field of study.
Jones, P. (1996) Humans, Information, and Science, Journal of Advanced Nursing, 24(3),591-598.(A copy with the figures included can be provided on request.)
HIFA profile: Peter Jones is a Community Mental Health Nurse with the NHS in NW England and a a part-time tutor at Bolton University. Peter champions a conceptual framework - Hodges' model - that can be used to facilitate personal and group reflection and holistic / integrated care. A bibliography is provided at the blog 'Welcome to the QUAD' (http://hodges-model.blogspot.com). h2cmuk AT yahoo.co.uk