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Living with coronavirus vaccine

The Conversation UK, an online publisher of popular scientific articles, is organising a webinar on the subject of the coronavirus vaccine:


Strathclyde will be represented by my colleague, Dr Lynn Williams, and your humble correspondent. It should be both a fun and interesting experience.

Click here to register and you will be sent joining instructions before the event. The event is free to attend and you get an opportunity to ask questions!

Vaccine vs. natural immunity

Have just seen a Twitter post by US Senator Rand Paul (Kentucky):

Firstly, Senator should be congratulated on doing correct math and comparing numbers (not a common feature among politicians, see below). There is a bit of a problem that we do not know whether either vaccine or natural immunity is lasting (and whether the 200 reinfections are a valid estimate, or represent initial values in a bigger wave resulting from loss of immunity), but there is also a deeper issue with these calculations.

And this is safety:

Naturally acquired COVID-19 immunity comes with significant side effects. Assuming 1% infection fatality ratio (IFR) which is a currently accepted value, COVID-19 leads to 1 in 100 serious side effects. In my medicine leaflet, this is listed under Common side effects. If a vaccine led to 1% deaths, it would not pass the regulations.

Without prejudging the safety of Pfizer and Moderna vaccines when they are widely rolled out, the current status is that the level of serious side effects is less than 1 in 10,000 which is classed as Very rare side effects.

I am not saying the vaccine is completely safe – we do not know this at this stage – but it appears much safer than the natural immunity.

I wish Senator was honest and not only mathematically competent.

Another example from today’s Twitter shows somebody who is neither honest nor mathematically competent.

Sadly, 50,000 divided by 5,000,000 is not 0.1% but 1%. I wish politicians:

  1. Knew how to do mental math, or at least knew how to use a calculator
  2. When the mistake is shown to them, they could say sorry and delete the tweet.


There has been quite a lot of excitement recently concerning the trials of COVID-19 vaccines. It remains to be seen when they will become widely available, whether they are as effective – as safe – as claimed. In the meantime, it is good to remind ourselves how the trials and their analysis are carried out.

My new article at The Conversation gives an overview of some numbers behind the vaccine trials and plans for the deployment. If you know Spanish, there is even a translation available!