Query for immunologists...we need about 70% of the pop. to be vaccinated for herd immunity; ie. at 70% we get R=1. So lets call it 3.5m vaccinations. Can we do 500k/month? So this takes 7 months to achieve? What’s the effect of increasing vaccination levels by 500k/mth on R? 1/
In Jan we will be facing the prospect of a further lockdown as cases will be rising fast. If we start vaccinations in Jan then how will this help the R number. If 70% vaccinations imply R~1, then is there a linear relationship between vaccination level and R? 2\
Eg. in early Oct the national R number was about 1.2. If this is our baseline “being careful” rate, and if 10% of the population get vaccinated then does this reduce this baseline rate? By 10% ish? If so will R fall by 10%/mth due to vaccinations, all other things being equal. 3\
Haven’t checked the maths. Probably not that simple — behaviours may change — but presumably there is pressure on R as vaccinations proceed. Is it enough to avoid L5 in Jan. Maybe if vaccinations proceed & if we manage to limit the Xmas spike to create some breathing room. 4\
So, a plan: keep L5 as long as poss (Dec 14?); EU approves vaccine mid-Dec, rollout Jan; extra careful for Xmas to keep cases low as poss for Jan; vacs start in Jan w/ L3+ restrictions (economy open/no home visitors); as vacs increases restrictions relax w/ cases thru to July.

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More from @barrysmyth

21 Nov
Some people have been asking about the ‘models’ I used in this graph to make case predictions beyond today. It’s very simple. There isn’t a model, at least not in the complicated way you might think. Wtf?!? Let me explain.
Instead of using a complex predictive model & having a debate about parameters etc. I just used the case trend/numbers from waves 1 (red) & 2 (blue) after aligning the relative case numbers based on their peaks, as shown. Both waves are similar so this makes sense. 2\
Next, I ‘predict’ the remaining cases in (wave 2) L5 by assuming the trend will match that during the same period in wave 1 (ie the red line between Nov 20 - Dec 4, since I aligned wave 1 from March-June with wave 2 today). This gives the dashed blue line from Nov 20 to Dec 4. 3\
Read 10 tweets
20 Nov
Level 5 seems well & truly stuck now, & each day brings a new even higher cases/day ‘prediction’ for an early Dec exit; its now 257 today, up from 223 yesterday. The problem is not only that cases are stalled/rising, but we have less and less time left to fix it before Xmas. 1/
That puts us >500c/d by Dec 25 & >900c/d by Dec 31, but that’s if transmission in Dec is similar to tx in Sept/Oct, which is surely very unlikely. Chances are, it will be markedly worse because of Xmas, so we’ll get more cases later in Dec & need a lockdown in early Jan. 2\
There are 19 counties on the naughty-list tonight (increasing transmission rates, week on week), up from 16 yesterday, including Dublin, and 6 of them now in the upper-right quadrant (high transmission & rising) which likely means further case increases in the coming days.
Read 4 tweets
3 Nov
How are things going in Level 5? Cases and positivity rates are coming down nicely. How does this compare to wave 1 and can this help us to predict where we might get to by December? Let’s have a look ...
I’ve aligned waves 1 & 2 using their peaks. The y-axis is the 7d moving average of daily cases as a fraction of each wave’s peak. Wave 1 peaked at ~872 c/d and came down to about 50 c/d by June. So far, wave 2 has peaked at 1169 c/d & its falling. Where will it fall to?
Next, I (naively) extend wave 2 using the corresponding portion of wave 1; very simple yes, but probably a reasonable, if optimistic, estimate that saves on the modelling.

It suggests that we will get to about 144 cases/day on Dec 4.
Read 5 tweets
2 Nov
Slovakia's drive to test its entire population over 2 weekends got off to a good start on Saturday with 2.5m tested and 1% positivity. Those 25k positives are now in quarantine. A voluntary programme with opt-outs required to quarantine for 10 days.
Next weekend the second half will be completed and presumably another ~25k positive cases will be found. So approx. 50k people will be in quarantine for 10-14 days. The remaining >5.4m people will presumably be free to go about their business with limited restrictions. (2/n)
There will be false positives among the 50k positives, possibly a fair few of them, but the alternative is that everyone goes into lockdown so this seems like a reasonable trade-off. There will also be false negatives circulating but there shouldn't be too many of them. (3/n)
Read 17 tweets
1 Nov
This seems like an interesting experiment. Slovakia is testing entire population (5m) over 2 w/ends. Testing is ‘voluntary’ but those not participating must self-isolate for 10d. The first round covered 1m people with 1% positivity.
(1/n) @dwnews
In theory, absent issues with false negatives, could an approach like this drive the virus out of a country within a couple of weeks after testing? Imperfect because of false negatives and secondary tx during isolation, but it would surely do more than 6 was in L5 (for all) (2/n)
Eg, assume 1% positive rate from round 1 is correct, then Slovakia will end up with 50k people in isolation for 10-14days after a full testing cycle. After that cases will be the false negatives & secondary tx during isolation. (3/n)
Read 6 tweets
1 Nov
We can now see transmission rates after L3, as we began L5. Much better than start of L3. Almost all counties either in or near the lower-left quadrant (low transmission & falling). A great good from which L5 can do its work if we all do out bit.
link.medium.com/z5HrNtUB3ab Image
Here’s the same picture from just a few days ago ... we were moving in the right direction but still more to do. Image
And back at the start of L3 it was much worse again because by and large most counties had high and rising transmission rates (upper-right quadrant). So we have come some distance already ... Image
Read 4 tweets

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