Just a one liner-ish type post.
I had the privilege of listening-in to one of the weekly Royal College of Pathologist webinars on the SARS-CoV-2 virus, this one on serology testing. These webinars are really fantastic, they are given as a 15 minute presentation by a scientist at the top of their field, in the complete absence of political interference or the sort of financial pressures applied to produce a 100% specific, 98% sensitive serology test to make billions of dollars for a commercial company. They have spent their careers as coronavirus "enthusiasts". The presentations are by pathologists, for pathologists. They are technical and utterly honest (as far as I can tell).
So. There are three types of people in the world. If you have had SARS-CoV-2, confirmed by PCR, have been seriously unwell, hospitalised, needed supplementary oxygen and been considered for a respirator/ITU admission then the chances are good that you will be solidly seropositive for SARS-CoV-2 on a blood sample in recovery. I would suggest that your medical history might be quite a big hint in this direction, which might render the use of the serology test under these circumstances somewhat superfluous.
The second type of person has also had SARS-CoV-2, confirmed by PCR test, been clearly unwell but not so unwell as to need any hospital admission for management. With the best possible testing using multiple different antibodies and different test techniques these people are very, very difficult to detect on a serology basis. Many will be negative on serology within the limits of what we have available now and what will be developed commercially. That is worth thinking about.
The third type of person has never been ill, has never been PCR tested, has no idea whether they have been exposed to SARS-CoV-2 or not. These are the apparently healthy population, the sort of people John Ioannidis sampled in Santa Clara County.
Of the 3300 people Ioannidis tested, 2.5-4.2% turned out to be sero-positive. Listening to the RCPath webinar on the problems of serology testing in mildly unwell people (let alone those apparently never unwell) this implies that the values from Ioannidis might well be the absolute, rock bottom, tip of the iceberg minimum. Exposure has probably been much, much higher in this still healthy population.
I find that rather hopeful.
It is difficult to describe how badly I feel that the COVID-19 pandemic has been managed here in the UK. I don't make political posts on the blog (or anywhere else) but the level of utter incompetence of our current government is breathtaking. I suppose a different administration could have done worse, but that's hard to imagine.