Thread by @chrischirp

THREAD: latest covid situation in UK (mainly England) and what I think is going on...

TLDR: I *do* think there has been a recent drop in transmission, due to combo of different things. Might not be quite as big as seems and might not last.

(22 tweets)

2. UK cases have dropped quite a bit since 19 July, but gone up a bit again over last couple of days. 29K cases today keeps it higher than it was earlier in week but lower than last week.

3. Different patterns for each nation. But Scotland has been dropping consistently since early July in cases & positivity rate. Positivity rates still quite high though.

England dropping since 19 July & also seeing declines in positivity rate. It's not just fewer tests.

4. Regionally, all English regions and almost local authorities are dropping.

Biggest drops in the North of England from the highest peaks. Similar patterns in positivity rates, although they remain v high, esp in the North.

5. But there have been increases in England in last couple of days and these are seen in all regions.

So regions dropped together and have then (recently) risen together too.

6. Now ONS today showed increases in prevalence everywhere except Scotland.

But because you can test +ve a few weeks after initial infection, ONS often comes down later than *new* cases. Came down 2 weeks after Scottish cases...

Still, I'll return to ONS later!

7. If covid really dropping, we'd expect to see hospital admission dropping about 7-10 days later. We see that in Scotland, and we *might* be seeing it in England - admissions always lower at weekend though, so let's see what data says early next week.

8. Regionally there is some variation in hospital admissions - NW dropping and Midlands flattening but NE only just flattening and London and SW still going up...

But no doubt that vaccinations have massively helped us avoid the January disaster (@jburnmurdoch )

9. And just to say, even though hospital admissions/occupany much lower than peak (at the moment), it has implications for staffing & for capacity nonetheless as @NuffieldTrust pointed out today!

10. And yes, most hospital admissions are *because* of covid and not just with covid!

https://twitter.com/john_actuary/status/1421033502443769858?s=20

11. So what does the reduction cases mean? I think there are 4 main factors.

Firstly schools: 15% of pupils out of school w/e 15 July will slow transmission. And disproportionately in high rate areas in North & Midlands.

12. Plus since 19th far fewer tests being done by teens as they isolate or term ends.

ONS by age shows continued increases in kids - so perhaps many asymptomatic or slightly symptomatic being missed too.

So combo of less covid & fewer tests means ewer reported cases in kids.

13. Football - there was a big spike, particularly in young men, as England got all the way to the finals in the Euros.

https://twitter.com/jburnmurdoch/status/1419912847795146760?s=20

Accelerated growth due to that is now over. Cases have fallen less in over 60s (perhaps also delaying down hospital reductions).

14. Plus ONS ages (again) show that actually prevalence in 18-49 year olds is flat - only kids really going up. This supports idea that *new* infections in young & youngish adults might be falling.

15. Behaviour is also important. The ONS social survey a few weeks ago showed that most people were worried about 19th July.

16. And many intended to keep with protective behaviours - including wearing masks, trying to meet outside, opening windows, keeping social distancing.

What people aren't keen is doing lateral flow tests which could spot mildly or non symptomatic infections.

17. And, as it happens, after 19th July there was an increase in meeting people outdoors and indoors but NOT a massive jump. People didn't really change their behaviour...

Plus 6% (!) of pop said they were isolating. So the pingdemic might genuinely have helped slow things down

18. Finally, testing willingness... While I do think there are genuine falls, there might also be some reluctance to get tested.

Tests have fallen this week. Some of that is school holidays, some is less covid but some might be reluctance to need to isolate or ping your friends

19. When compared with the King's College symptom tracker app (where reporting symptoms carries no obligation for you or your contacts) you see flattening growth but not a drop.

20. I *don't* think we've reached 'herd immunity'.

If we had, you wouldn't expect drops everywhere at same time (different levels of immunity), & you'd expect a flatter peak. Plus Israel, which has higher vax rates, is still climbing. We've just not vaxxed enough.

21. So basically, I do think a combo of school disruption, pingdemic, no football and cautious behaviours has brought cases down. I think some reluctance to get a test might have made that look more dramatic.

I also think latest opening only now starting to show up.

22. School holidays will help, but changing requirements re isolation, less cautious behaviour plus big events (e.g. Latitude festival) likely to offset that. I expect cases to go up again.

Return from holidays to schools & unis in Sept will be potentially difficult. /END

PS note that in Scotland, football ended earlier, schools broke up for holidays at the end of June and their final opening (clubs etc) isn't until mid August.