Thread by @sciencescanner

@JohnOspanov Ok. So time for some more speculation on where we are in the #COVID19 epidemic in UK. Yes, what follows is my OPINION so don’t waste your time telling me I’m wrong - because none of us know

1/n

@JohnOspanov My guess is that when random sample serology is reported for the UK we will have 5-10% antibody positive (5% if you did it now, 10% if you wait til next weekend)

That will also reflect some geographic variability with some area below 1% and others above 20%

2/n

@JohnOspanov Why that high? Because the evidence is that the UK was “lucky” and imported lots of independent simultaneous infections - possibly from skiers returning from Val d’Aosta in Northern Italy

3.n

@JohnOspanov There are two lines of evidence for that statement: (1) genomic analysis of the virus explained in the excellent thread

@JohnOspanov The evidence for that statement comes from this excellent thread about the genomic evolution of the virus:

https://twitter.com/trvrb/status/1243754919623974915?s=21

https://twitter.com/trvrb/status/1243754919623974915

@JohnOspanov And from the observation I made back in February of the geographic spread of the early cases. Both suggest the UK had widespread parallel exposure in contrast to the much more focal exposures in Italy, US, France, Spain and China (but similar to what Iceland has seen)

5/n

@JohnOspanov This is “good” because it distributes the small percent of severe cases more and helps stop healthcare capacity being overwhelmed in any one locale

6/n

@JohnOspanov But it is also good at generating an effective herd immunity by rising the number of immune people THROUGHOUT the population, rather than just within the clusters

7/n

@JohnOspanov With clusters the virus has nice naive populations to rip into around the boundary of the cluster. But with distributed immunity you get breaks in each transmission chain. A homogenous 10% immune population is at much lower risk than one where the 10% immune are all together

9/n

@JohnOspanov But all this remains speculation until we get random sample serology data from a wide geographic spread across the UK. No word yet as to whether the first serology tests will be used that way - but I’m optimistic @uksciencechief will do so

10/10