1st June

It is said you can divide the British population into those who trust The Chancellor of the Duchy of Lancaster and those that don’t. However whichever side you are on, I think you can agree that the best Teachers have had to go on is a vague statement that they should start bringing back children on 1st June. There are no data that I have seen which can be used as evidence. So I am disappointed to give the first public model of the risks involved in going back to school. My working out is going to be riddled with false assumptions. I apologise for inconsistent rounding before the final stage of the calculations. This is due to the fact the numbers are all very speculative and all I want to do is create is a polemic about how we can calculate the risk.

Isle of Sheppey has approximately 3750 primary children. For the only school on the island that I could find with the proportion per class they are evenly spread out through the age range, so 7 groups and 3 going back equals 1600. With 1 adult per 10 children this gives about 1800 souls.

Now here come some more big assumptions. Given an r of about o.8 and 208.1 (a degree of accuracy I would not use) per 100,000 in Swale confirmed positive and also 40 % of cases asymptomatic. I will assume the 208 are self-isolating but they will have passed it on to 0.8*208 = 166

208/60*40 =173 these 173 are still at large and could have passed it on to 0.8*173 = 138

For a total of 166+173+138 = 477 per 100,000 gives 477/100000 * 1800 = 9 infections in the new school population.

This actually nicely works out as 1 per school. But as the schools are different sizes I will work it out per class of 10. 10 given the size of a classroom, is the only number I think a possibility of non-transmission could occur.

So 9/160 = 0.06. So 6% of classes would have an infection. Another big assumption, that of passing it on to your child or teacher in the month, say 20%, this gives a 0.06*0.2= 0.012 chance of your child or teacher catching SARS CoV-2. 1 in a hundred. Now this risk will have to be weighed according to your family. I.e. ages, risk groups etc.

For me a 55-year-old male. 246,406 confirmed positive with 40% asymptomatic gives 410,676 cases. In my age group 2547 deaths gives 2547/410676= 0.006 chance of dying if infected. In this simple example I will ignore getting significant organ damage.


So 0.012*0.006 = 0.000072   chance of death in that month due to Covid 19

What does this mean? Risk of death UK in a year driving 0.000059 so about an order of magnitude (12) more risky. Although better than when my partner is driving. As the odds of dying in a vehicle accident are already considered high, these odds do not seem good. http://www.bandolier.org.uk/booth/Risk/trasnsportpop.html

Since completing these calculations I think it is interesting that I now have some degree of knowledge about the risks. I am also feeling a sense of shame that I have had to work it out on my old Casio rather than get the data from our Government.

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