Read on Twitter
What will happen next? What do the statistics mean and how should they affect policy?
These are the big questions facing the world not just the UK
A sheep thread on how it looks from Yorkshire
1/
These are the big questions facing the world not just the UK
A sheep thread on how it looks from Yorkshire
1/
Warning: I am a sheep not an epidemiologist.
My aim is to throw a few numbers around, not as a prediction but to examine the sensitivities involved and identify what that might mean for future policy. I readily admit Iâm not an expert.
Feel free to chip in nicely. 2/
My aim is to throw a few numbers around, not as a prediction but to examine the sensitivities involved and identify what that might mean for future policy. I readily admit Iâm not an expert.
Feel free to chip in nicely. 2/
Unproven assumptions:
1. Exposure to CV results in immunity until a vaccine is available.
2. Hi levels of community immunity would inhibit transmission of CV in future waves of the epidemic.
3. Hi levels of immunity would result in easier measures. 3/
1. Exposure to CV results in immunity until a vaccine is available.
2. Hi levels of community immunity would inhibit transmission of CV in future waves of the epidemic.
3. Hi levels of immunity would result in easier measures. 3/
So how many people will be immune by the end of wave1? How many people will have had CV?
Iâm going to use death statistics (remember these are people not numbers) to examine this.
I am going to assume that by the end of the first wave 30k people will have died of CV 4/
Iâm going to use death statistics (remember these are people not numbers) to examine this.
I am going to assume that by the end of the first wave 30k people will have died of CV 4/
This pessimistic *working assumption* takes into account:
1. We are only halfway through the bell curve distribution.
2.There is a lag in recording deaths.
3.Some deaths outside hospitals are being recorded as something else. 5/
1. We are only halfway through the bell curve distribution.
2.There is a lag in recording deaths.
3.Some deaths outside hospitals are being recorded as something else. 5/
This implies:
If:
1. 1% of cases die =>total cases 3m or 4.5% of population (66m)
2. 0.1% of cases die=>total cases 30m or 45% of population
3. 0.5% of cases die=>total cases 6m or 9% of population
6/
If:
1. 1% of cases die =>total cases 3m or 4.5% of population (66m)
2. 0.1% of cases die=>total cases 30m or 45% of population
3. 0.5% of cases die=>total cases 6m or 9% of population
6/
Case 1 = high mortality, low transmission
Case 2 = low mortality, high transmission
Case 3 = inbetween
7/
Case 2 = low mortality, high transmission
Case 3 = inbetween
7/
If Case 2 is correct then we are starting to achieve herd immunity and life should become easier.
If Case 1 is correct then we have barely scratched the surface of the epidemic and weâd be virtually starting from the beginning when the next wave comes (assuming no vaccine) 7/
If Case 1 is correct then we have barely scratched the surface of the epidemic and weâd be virtually starting from the beginning when the next wave comes (assuming no vaccine) 7/
So which outcome is most likely? I will refer to two more pieces of evidence.
First, studies suggest that 50% of cases are asymptomatic. For Case 2 that would suggest that 15m or 22% of the pop had been exposed to the virus AND had exhibited symptoms. 8/
First, studies suggest that 50% of cases are asymptomatic. For Case 2 that would suggest that 15m or 22% of the pop had been exposed to the virus AND had exhibited symptoms. 8/
But is this likely?
Certainly many folk (inc me) have reported mild symptoms.
However to date, we have conducted 267k tests and found 55k cases (20%) - people mainly presenting at hospital.
This implies that 80% may think theyâve had CV but in fact havenât. 9/
Certainly many folk (inc me) have reported mild symptoms.
However to date, we have conducted 267k tests and found 55k cases (20%) - people mainly presenting at hospital.
This implies that 80% may think theyâve had CV but in fact havenât. 9/
IMO, this makes Case 2 seem less plausible although the evidence is partly anecdotal.
I have read suggestions that Case 3 is more likely but even this would result in immunity for only 6m or 9% of the population. 10/
I have read suggestions that Case 3 is more likely but even this would result in immunity for only 6m or 9% of the population. 10/
What does this mean?
First, my figures are only a tool for examining the sensitivities but it seems that however you play around with the figures itâs quite feasible that we will end Wave 1 with low levels of community immunity. 11/
First, my figures are only a tool for examining the sensitivities but it seems that however you play around with the figures itâs quite feasible that we will end Wave 1 with low levels of community immunity. 11/
This poses a terrible problem for policy makers. Itâs possible that we would need several waves of disease before immunity had built to a good level.
If each wave requires the measures we have in place now the overall cost will be terrible, financially and in human terms. 12/
If each wave requires the measures we have in place now the overall cost will be terrible, financially and in human terms. 12/
OTOH, if measures are relaxed too much then the resulting deaths get compressed into a very short timescale posing a very tricky decision for all governmentâs across the world. 13/
If nothing else, this thread highlights the crucial need for community immunity testing to determine the true position.
Without it, a decision on what to do next looks very hard to make.
Hopefully, international efforts will also help 14/
Without it, a decision on what to do next looks very hard to make.
Hopefully, international efforts will also help 14/
But to end the thread,
The *absolute* priority *has* to be a vaccine.
Drop everything, build a factory, throw the cash but get us a vaccine. Now.
Stay safe
End/
The *absolute* priority *has* to be a vaccine.
Drop everything, build a factory, throw the cash but get us a vaccine. Now.
Stay safe
End/
