The latest leaflet that was handed out with my vaccination got me thinking. According to the leaflet two doses reduces the chance of death by a factor of 20. If you look back at the peaks we had that would still mean more than 50 deaths a day (about 20,000 a year) if we had widespread infection. Still quite high. The key protection is actually keeping the infection rate low.
This is why the other figure in the leaflet is so important – the risk of catching and passing on the infection. The leaflet says one dose gives about 2/3 reduction. Remember that R0 that was estimated to be about 3 – well that means if we have 100% vaccination rates with one jab we will just about reduce transmission to a level that doesn’t increase or decrease much. But we know that we are not going to get 100% of people vaccinated. So a single jab does not allow total freedom to be restored.
Two doses would reduce the chance of passing on an infection by 85% apparently. That would mean we need to get a 75% vaccination rate to get the underlying reproduction rate low enough. Where are we at the minute? Well a simplistic model would suggest out current basic R value is around 1.5 (half where it used to be).
So my protection will be mainly as a result of enough people having a full vaccination. And enough people having a vaccination depends on each of us – on me. So I get vaccinated to protect you from infection, and the fact we are all vaccinated protects me from infection.