Read on Twitter
1. Many people are saying that they are not spending Christmas with family as it is “not worth the risk”. In order for a person without coronavirus symptoms to “kill their Granny” this Christmas, a very specific chain of events has to occur. But how likely is it?
2. First of all, given that you have no symptoms, what are the chances that you are infected with Sars CoV-2? The ONS estimates this to be 1 in 115, or 0.87%
https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveypilot/latest
https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveypilot/latest
3. Now, imagining you are infected, but you don’t have any symptoms, what is the probability that you will infect somebody else with Sars CoV-2? Recent studies show this is around 0.7% https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2774102
4. If we multiply the probability of these two events, we can calculate the likelihood of you a) being infected & b) passing that infection on without symptoms. This gives a figure of 0.006%
5. To put that figure in context, it’s roughly the same as your chance of dying in a car crash over the course of any given year.
http://www.bandolier.org.uk/booth/Risk/trasnsportpop.html
http://www.bandolier.org.uk/booth/Risk/trasnsportpop.html
6. But if you infect someone, this doesn’t mean that they are going to end up dying of Covid pneumonia. Far from it, in fact. There is a lot of debate regarding the IFR of Sars CoV-2, but the Centre for Evidence-Based Medicine puts it at roughly 0.5%. https://www.cebm.net/covid-19/estimating-the-infection-fatality-ratio-in-england/
7. Now, if we multiply the chance of infecting another person (without symptoms) by the fatality rate, we can estimate that the risk of “killing” one of your relatives is roughly 0.00003%, or 1 in 3 million.
8. Obviously there are a lot of caveats. If one of your relatives is very old and very ill, then the IFR is going to be higher. If they are relatively healthy, it’s going to be lower.
9. But there’s another caveat. PCR tests. The first number we used (the number of infected individuals in the UK) is based on positive PCR results. It is possible that only 3% of these positive results are accurate.
https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa1491/5912603
https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa1491/5912603
10. Which means that the risk of a person “killing” a relative without any discernible coronavirus symptoms may well be as low as 1 in 30 million – the same sort of likelihood of you winning the National Lottery.
11. Clearly, it is for individuals to assess risks for themselves and make decisions accordingly. But they should do so in the knowledge of how big those risks actually are. And nobody should be calling others "irresponsible" for taking a risk this minuscule.
12. Finally, this risk isn't just the justification for 'cancelling Christmas', it's the justification for all of it. Lockdowns, masks, school closures, undiagnosed cancers, suicides, stillbirths, unemployment. All done because we were told this specific risk was just too high.
P.S. this thread, I hope, puts this cartoon in the proper context.
And shows why all the people who accused me of being "dangerously irresponsible" for drawing it, were very wrong indeed.
And shows why all the people who accused me of being "dangerously irresponsible" for drawing it, were very wrong indeed.
