I’ve just been shouting at an eminent medic (he couldn’t hear me – he was on TV) for saying he had ‘validated’ Chinese antibody kits by using them on a handful of staff and comparing the results with a more sensitive PCR test. I have no idea how good a physician he is but he clearly bunked off all his statistics lectures.
Everyone, it seems, is banging on the need for mass antibody testing to see who’s had it or has immunity, and it’s been suggested ‘immunity passports‘ are the way forward. And it’s an appealing notion.
The problem is using antibody tests in this way will lead to many, many, many more deaths.
I’ve written before about different ways to test for coronavirus and many would argue the only feasible route to mass testing is a finger prick antibody test. I don’t want to get into the weeds of immunology in this post, the point is:
If you can measure the specific IgG antibody raised against – say – this coronavirus, you can tell if someone has been exposed and is likely immune. And IgG is the one you can detect waaaaay after you’ve recovered. (IgM is the one that turns up first in an infection then wanes as the infection does).
I also don’t want to get into “how much long-term immunity do you get to this coronavirus” – that’s a different and complex question. Bear with me here and just accept:
So, if we can accurately test for IgG we can make a pretty good guess if someone is immune and therefore can go back to work without putting themselves or others at risk.
So far so simple. But it’s biology. It’s fucking complicated. I’ve told you that before. Lots. Keep up, FFS.