Thread by @chrischirp

THREAD on England short term Covid outlook:

Thread on some of the implications of latest SAGE SPI-M models about English roadmap, step 4 & Delta.

TLDR: medium term v uncertain but in short term expect hospital admissions to keep rising.

2. They point out that current increase in cases will only stop if at least one of below happens:
1) people change their behaviour
2) govt changes policy (more restrictions and/or more public health interventions)
3) enough immunity is built up (through vax or infection)

3. Govt is basically doing 3 -> trying to get as many people fully vaxxed as fast as possible & tolerating high infections in younger people in the meantime.

It also delayed step 4 deciding (wisely!) that throwing petrol onto the fire wasn't a good idea.

4. Note that this *isn't* a change in policy since the roadmap was designed to be flexible. Unfortunately all the govt rhetoric beforehand obscured this fact.

But now, until option 3 (more immunity) kicks in, we have a situation of rapidly increasing cases.

5. SAGE note that while vaccines have meant fewer infected people need hospital than before, the link between cases & hospital is still there and has stabilised recently so that daily hospital admissions are now about 4% of what daily cases were 10 days earlier.

6. This means that if cases double, then admissions would be expected double too (so if 100 cases results in 4 admissions 10 days later, 200 cases would result in 8 admissions etc).

7. We have seen cases double every 9 days or so recently. We can expect hospital admissions to do so as well.

96 people with Covid were admitted on 4th June. 9 days later, on 13th June, 187 people were admitted - almost double.

8. As SAGE points out, 187 admissions is 4 doublings away from Apr 2020 peak and less than 5 from Jan 2021 peak.

At 9 day doubling, that's *5 to 7* weeks from now - just after new July step 4 date...

9. The next ten days are mostly locked in from recent case rises. That means in 10 days we will likely see over 250 hospital admissions a day (using 4% relationship as approx estimate).

10. But then what? how soon will the vaccinations kick in to stop growth? Good weather will help... as will school holidays from mid July.

But over *next* few weeks, cases will keep growing.

11. Some signs that growth is slowing a bit in England - perhaps cases are doubling every 14 days now instead of 9. This is good as it gives us 8 weeks instead of 5 before reaching Apr 2020 admission levels.

And *more* time for vaccinations, behaviour & policy to prevent this.

12. Things are really uncertain as to when & if vaccination will stop hosp admissions on its own - too much depends on exact transmissibility, severity, vax resistance of Delta and vax uptake.

13. Delaying the roadmap 4 weeks helps bring down cases *and* hospitalisations, AND also gives time to resolve some of the uncertainties.

At the moment estimated peak daily hosp admissions range from a few hundred (best case) to well over Jan's 4K peak (worst case) in Aug/Sept.

14. Speed of vaccine roll out has an impact but *not* that big.

Different assumptions about Delta's characteristics (esp transmissibility) have bigger impact on size of peak.

Plus we don't know how waning vax protection will affect things.

15. My personal feeling, assuming 19 July goes ahead & little vax waning, is that there will be at least 2 or 3 more doublings before things *might* reduce. That means tens of thousands of daily infections and somewhere between 1,000-2,000 daily hospital admissions in 6-8 weeks.

16. This puts me at the more optimistic end of the SAGE models (!) - mainly cos I think their central vax efficacy estimates are still a bit pessimistic. I hope that if I am wrong it's cos I am not optimistic enough - so much uncertainty still about the medium term.

17. If I'm right, then this would not be as bad as we saw in Jan or last April (in terms of hospitals or deaths) but it *will* be bad. The NHS is already stretched with its backlog - we shouldn't be adding *any* more stress.

18. Even 2 weeks of tens of thousands of daily cases means hundreds of thousands of overall cases, which means tens of thousands more (mostly young) people living with long covid.

It means hundreds of thousands of chances for further mutation that can resist vaccines.

19. And these scenarios *are* avoidable. We are *still* not properly supporting people to isolate (financially and practically), we aren't testing contacts of cases, we aren't supporting workplaces and schools to improve ventilation

20. We aren't empowering local public health directors to impose restrictions if they deem it necessary - nor local alities with the resources to support affected people and businesses.

We aren't communicating the much wider list of symptoms that should prompt a test.

21. And we *still* haven't fixed our border policy, leaving us open to importing (and exporting for that matter), new, even worse, variants.

22. *if* we can avoid new variants emerging or being imported, we should be in a much better position by end of September - especially if we can extend vaccine protection to secondary school children.

But we mustn't accept a narrative that this summer wave was or is inevitable.

23. The policies that allowed Delta to become dominant in 8 weeks & lack of govt interest in actually reducing cases, will now lead to more ill health, more strain on the NHS and more deaths.

We should be furious. /END