How important is COVID-19 epidemic?

I have recently been seeing a number of posts on Facebook still questioning the size and importance of the COVID-19 outbreak. Although it has now been going on for over 4 months, there are still people who make some of the following statements:

  1. There is nothing really happening as it is not worse than usual with seasonal flu;
  2. There is an epidemic but the level of deaths is nothing compared to other diseases;
  3. There is an epidemic and there is a lot of excess deaths, but the strategy chosen to stop the outbreaks causes more deaths.

As this blog is about statistics, I will use the publicly available data for England and Wales and for Scotland to address these points. The numbers are official records of deaths as collected by registrars and so are not covering the most recent weeks. On the other hand, they are very reliable, as every death in the UK needs to be reported. I will be more cautious about the associated cause of death, as this potentially involves a medical interpretation or tests and is, therefore, more open to criticism.

By using centrally collected data I will avoid a problem of self-selection which makes many Facebook posts so unreliable. Typically, in these posts, we are presented with an opinion of or an interview with a medical doctor or a nurse who talks about their own experience in a particular location. We need to understand that the outbreak levels in large countries like China or the US can be extremely uneven so that we can get a very big problem in New York City and practically none in the rural location far from a big city. Similarly, an experience of somebody in London might be very different from the one from the Scottish Highlands or the Outer Hebrides.

Selecting either one or another and saying this applies to the whole country is disingenuous at best and a dangerous lie at worst. This is why I just want to stick to overall official data. But if you think that the Registrar data are biased and incorrect, you can stop reading now and forget about my arguments.

Let’s look at the first claim. To address it, I will just use the number of deaths recorded per week in the UK. The data are publicly available and there is a nice visualisation of them available here. The graph below shows the number of deaths in each week of 2020 as officially reported, compared with the number of deaths in that week over the last 5 years.

The deaths in previous years follow the ‘usual’ pattern, higher over wintry months, going down as temperatures go up. The numbers are between 10 and 15 thousand. The population of England is about 56 million and of Wales about 3 million, together 60 million (Scotland adds another 6 million). The resulting death rate is 17-25 per 100,000 people, about right for a country like the UK. A lot of winter deaths are associated with seasonal flu, but this goes away in spring which is why it drops down in March.

Up until 17-24th March the deaths were actually lower than the average over the last 5 years, but within a usual variation. However, there is clearly something unusual about the deaths in the weeks starting from the week of 27th March. The epidemic in the UK started in early March, but it takes several weeks for the first critical cases to succumb to the disease. What we see in the data is the massive increase in late March and early April is the result of COVID-19 epidemic. As of 17th April, the last week for which we have data (it takes about 4 days for the death to be registered), the number of excess deaths is more than double the ‘normal’ number and getting worse.

Note that this includes all deaths, whether COVID-19 related or not (points 2 and 3 above); I will address this in a separate post.

While we are looking at the data from England and Wales, let’s see what the regional differences are; shown here is the number of weekly deaths per 100,000 inhabitants.

Broadly speaking, London is hit worse. South East which is quite affluent, had the lowest death rate before the COVID-19 outside of London, but was then hit quite badly. Wales and North East, which are a mixture of rural communities and relatively deprived post-industrial towns were hit relatively less.

Wales is particularly interesting, as the level of deaths is here similar to the one seen in January, possibly associated with seasonal flu. But March is not a season of flu and so the excess of 7 deaths per 100,000 inhabitants is very unusual for the time of the year. I will show Scottish data in a later post, as I am waiting for the April data to be released.

To summarise in response to point 1:

  1. There is nothing really happening as it is not worse than usual with seasonal flu;

the answer is that indeed there is actually something happening and is not usual for this time of the year. While for rural communities we could possibly currently claim similar levels of death as at the seasonal influenza peak, firstly, this is not seasonal influenza season, and secondly, urban and affluent places like London or South East – or New York – are hit even more.

In the subsequent posts I will look at other points.