Covid-19 — Regional Analysis — Putting the Spotlight on London
By: Matthew Bottomley
Tags: Covid 19, Fact Checking, Data Visualization, Pandemic

Covid-19|Fact-Checking

Confused by various sources of information that circulate about Covid 19? Well, you’re not alone. This article focuses on the London Region, it follows the same type of analysis previously conducted at a national level. The analysis uses official government data from the UK’s office of National Statistics including daily flash numbers from: https://coronavirus.data.gov.uk/ .

London Weekly ONS Death Data Comparison With Prior Years

source: ONS

Key Points

The initial outbreak is very clear within the data, however, the remainder of the year appears to falls within expected norms — apart from a slight blip around week 46.

To illustrate this further the Chart below shows the weekly difference in overall deaths between 2020 and the average of the five years previously.

Surprisingly, this chart clearly demonstrates that within London, that apart from the initial outbreak there has been no noticeable change in overall deaths through the rest of 2020.

Note: This is in stark contrast to what we are told concerning increasing Covid-19 Deaths and Cases. So what picture does the regular Covid-19 reporting show?

The Daily/Weekly Covid-19 Data

Note: there is often a lag in the published data so the final week’s figure is subject to change.

Overall the data shows a steady increase in deaths from the week commencing 19th September. In total this amounts to around 1,300 deaths in the London region.

Bearing in mind the overall year on year comparison shows no change in London Deaths, it seems reasonable to assume that up to mid-December, the reported Covid-19 deaths within London have been offset by fewer deaths due to other causes — most likely the Flu. Meaning that overall London is in a similar position to prior years.

On face value, this is great news, however, this may not be the end of the story and it is likely that London will begin to see further increases as we enter the heart of winter:

The relationship between Test Results, Hospital Admissions and Deaths:

We can anticipate that the lifecycle of Covid-19 like any similar disease would follow a number of stages from initial infection through hospitalisation then death. The ONS publishes daily data that allows us to examine this relationship. The following three charts show this relationship:

Positive Tests to Hospital Admissions:

The graph demonstrates that there is a very close relationship within London from positive tests to hospital admission. The time lag appears to be short, around one week.

The impact of the national lock-down is unclear. It is possible from the data to conclude that it halted the increase in cases but no more than that.

Within London it appears that 6.5% of positive cases result in hospitalisation within around one week. Without doing any form of statistical analysis the relationship between these two factors appears to be strong.

Hospital Admissions to Death

Note: due to reporting anomalies, the final week’s death figure is likely to change (upwards), it shouldn’t at this stage be taken as a sign that deaths are likely to fall — in reality they are likely to increase in line with the increase in positive tests.

Again the relationship between hospital admissions and subsequent deaths appears clear within the graphed data: it appears that approximately 20% of hospital admissions end in Covid19 death three weeks later.

taken together, the relationship between Positive Tests and subsequent Death

Based on the data it appears that for London roughly 1.3% (6.5% x 20%) of positive cases results in deaths with a lag of between one to three weeks.

Looking again at the impact of the national lock-down it is possible to suggest that it did result in stabilising the increase in cases but no more and that, unlike the earlier lock- down any benefit was short lived.

Indeed, the rapid increase in cases post lockdown this time around adds further evidence to support the argument that Covid-19 behaves like a normal flu — ie is virulent over winter but almost non-existent over the summer months.

This position will become clearer as death data becomes available for the next few weeks.

Future Prediction

Based on the relationships identified above, I have developed a simple model to forecast the number of deaths (and hospital admissions over the next three weeks). This reveals the following:

As with all models, time will tell, however, it is apparent from the graph that the model holds up well in predicting actual deaths to date. The basis is a three week delay from positive test to death and 1.3% of positive tests resulting in death. Based on current test data this suggests that deaths will continue to rise into the new year.

London Summary

London was the most impacted region in terms of deaths during the initial outbreak, with around 10,000 excess deaths during that period. However, since then the number of deaths in the region has remained in line with prior years despite a reported volume of Covid-19 deaths in the region of 1,300 excess deaths. The natural conclusion of this is that to date these excess deaths have been offset by either reductions in other sources of death, or that such deaths would ordinarily have occurred due to different strains of Flu (this seems the most likely explanation at this stage). The continued sharp increase in testing, and the model developed to predict future deaths suggests that London will begin to see increases above and beyond normal figures over the rest of winter. Indeed the model developed above suggests we will begin to see deaths above and beyond normal levels over the next few weeks. Overall and to-date it appears that the second National Lockdown has at best delayed the rate of infection within the London area. This position will become clearer over the next few weeks. The London data supports the theory that Covid-19 behaves like the normal flu — essentially dormant over the summer months whilst being virulent over Winter.

Next Steps

To validate the data demonstrated here, I shall complete similar analysis for the other English regions. Note: this may also throw light on this analysis and lead to an update to the conclusions reported above.