I read the paper, it is interesting, but definitely has flaws. The self selection bias is a real issue particularly with the small numbers involved.
On the other hand, I bet the overrepresentation of white people with access to Facebook and time to drive in for testing in their sample pool would favor true prevalence on higher end of estimates, as minority populations and lower class populations likely have a higher prevalence of this disease at this time. Also it seems their sensitivity estimate based on their own samples was much lower (67%) than the manufacturer sensitivity estimate (92%). If the local data is more accurate, then true prevalence higher.
Bottom line, this is preprint, not peer reviewed, and probably shouldn't be in public domain at this time.
On the other hand, I bet the overrepresentation of white people with access to Facebook and time to drive in for testing in their sample pool would favor true prevalence on higher end of estimates, as minority populations and lower class populations likely have a higher prevalence of this disease at this time. Also it seems their sensitivity estimate based on their own samples was much lower (67%) than the manufacturer sensitivity estimate (92%). If the local data is more accurate, then true prevalence higher.
Bottom line, this is preprint, not peer reviewed, and probably shouldn't be in public domain at this time.