Thread by @ewanbirney

For COVID watchers, in particular journalists, a primer (again) to get you through what - best case - will be a bumpy month and could possibly be going the wrong way on the numbers.

(Context: I am an expert on one area - human genetics/genomics; I am one-step-away from experts in other areas; I have one substantial COI on testing in that I'm a long established consultant to Oxford Nanopore which has made a new COVID test)

I will keep banging this drum - your (and government's) solid ground is hospitalisations and random sampled surveys (REACT and ONS in the UK; I think there are equivalent in France and Germany; could French and German pros respond. I don't think there is a regularly one in Spain)

Not only do daily numbers go up and down due to all sorts of reporting fluctuations (it is super hard to do this; don't confuse an easy to use/download website into making you think it is easy to even get the numbers) but also testing strategy is now broadening out

For example, there is more asymptomatic testing (healthcare workers, care home workers, universities) though at different cadences. The presence of more back tracing (enhanced tracing in UK speak) means opportunities for targetted local asymptomatic testing.

Asymptomatic testing is ideally closing the gap between estimated cases (from surveys etc) to known (with isolation etc). In contrast, testing capacity and logistics issues (people unable to get a test) means tests are being rationed or prioritised in often changing ways.

In this case, it is perfectly possible lower case numbers reported on a day is about a change in capacity/logistics and how that interacts with previous test seeking behviours (mandated or encouraged).

So - where possible - stick to your solid ground, and say wisely "we will have to wait for the next ONS survey".

Some other things which I think don't get enough attention in the UK context:

1. Northern Ireland. Because the surveys often don't reach there we have a less rounded dataset there, but the case data does not look like it is going the right way.

2. The regionality of UK rise in cases, and the regionality of control (North West is a big region, and you want to get inside of Bolton/Liverpool/St Helens etc). Frustratingly having argued you should know your solid ground, you have to go off case levels numbers here.

3. Contact tracing - these are the hard yards of infectious epidemiology both in call centres who know what they are doing and also house-to-house in high areas. I am now at a two-steps-away expertise zone from this, but lots of hard work to do well here.

4. Isolation support and isolation compliance. It is a key part to this phase and there is no point testing and contact tracing if the action is not there. Again, I think working this out from London/Hampshire zoom calls is not the same as a Manchester/Newcastle perspective

How many people isolate? Changing their behaviour alot is probably as important as "not seeing anyone at all" - but what do people actually do? For the people who do less, why is it in a "how do we make this work for everyone" way?

I'm afraid my understanding of French, German and Italian contact tracing and isolation is poor, beyond that Germany really seems to do it well (Go Germany!) and I think Italy has really improved from March (Go Italy). French feels, from afar, similar to UK.

Spanish is always super-complex because here there is no "Spainish" way - there are the regional health regions with plenty of variance in approach; also makes understanding it from the outside super-tricky. I hope Madrid and other hot areas in Spain get it under control.