Coronavirus : Update 18 from the Epicenter

Posted by in Coronavirus

After several weeks in lockdown, several parts of the world are starting to ease restrictions on movement.

Concentrating on our 4 countries, probably the graph which best illustrates this dynamic is our slowdown-chart. We’ll concentrate on cases as they lead deaths by 2-3 weeks :

Full Epidemic
Final half of Epidemic

The US is yet to dip on its way to a million cases; the UK has levelled off; Italy has stalled, but without seeing a true decline, and Germany is in free-fall.

There have been a few headlines recently predicting that the UK could end up with the highest number of fatalities. I’ve dragged out this old chart that I used back when only Italy saw exponential growth. If you remember, it offsets each country by a different number of days in order to align them with Italy and give a better picture of the relative death rates. You can clearly see that the UK is on exactly the same path as Italy followed :

Germany’s case to death ratio and absolute mortality numbers are also so incredibly low (see below), that they are able to lead the way out of lockdown, confident that they can handle the consequences :

Germany’s case to death ratio is extremely low (25% of Italy’s)
…as are their total death count (20% of Italy’s)

It’s also pretty clear that the difference in infection rates and mortality we see between countries is replicated between regions / states and cities. It can be politically useful, but ultimately misleading to talk about a country as large and diverse as the US as though it were hit uniformly. Trump made that error in Saturday’s coronavirus task force briefing :

“on a per capita basis, our mortality rate is far lower than other nations of Western Europe, with the lone exception of possibly Germany. This includes the UK, Switzerland, Belgium, the Netherlands, Italy, France.”

President Trump
  • Germany: 6.07 deaths per 100,000 people
  • United States: 13.71 deaths per 100,000 people
  • Switzerland: 17.35 deaths per 100,000 people
  • Netherlands: 22.80 deaths per 100,000 people 
  • United Kingdom: 26.14 deaths per 100,000 people
  • France: 31.09 deaths per 100,000 people
  • Italy: 40.79 deaths per 100,000 people
  • Belgium: 52.51 deaths per 100,000 people

This is technically a correct statement, however, the US only has 94 inhabitants per square mile compared to 991 in say, Belgium. The US has a population of 328 million to Belgium’s 11.46 million. NY state alone is a closer match to Belgium, with 19.45M inhabitants and a population density of 421 per square mile.

  • Belgium: 52.51 deaths per 100,000 people
  • NY state : 107.25 deaths per 100,000 people

Anyway, the point isn’t that the US administration is manipulating the narrative for political gain – the point is that we should be making decisions based on what’s happening at a regional level, which is why we’re producing these graphs of Rt that clearly show big differences within each country :

Italy Infection Rate Curves per Region 23/04/2020
UK Infection Rate Curves per selected Region 23/04/2020
US Infection Rate Curves per selected Region 23/04/2020

The problem is that you can’t really make regional decisions unless you stop migration between regions. This was illustrated during the initial stages of the lockdown in Italy. The government made Lombardia a red zone and 100,000 people promptly fled to their weekend homes in other regions.

The most efficient thing to do would be to use case numbers, infection rates, population densities and hospital capacities to bring regions back online ‘on merit’, however it would require extreme social discipline to make it work. My expectation – at least in Italy – is to treat the whole country according to its worst region. This would be consistent with the ‘we’re all in this together’ theme that has worked pretty well so far to keep the whole country at home.

This does raise a nagging question : just why have we seen such crazy disparity between not dissimilar cities within the same country? Here are the very latest numbers from Italy :

Milan is a densely populated city with an international airport, but did you ever go to Rome? It’s packed with visitors from all over the world. 2020 is the official Italo-Chinese Year of Culture (yes, it’s true..!) and Rome airport planned to handle more flights from China than the rest of the country’s airports put together (>1M). There were definitely infected people in Rome in January and February. People are also more touchy-feely than in Milan, and median age is higher in Lazio than it is in Lombardia. So why were there 12 times fewer cases there and 35 times fewer deaths?

We can ask ourselves the same question in the US (NY vs LA) and even in China. Yes, they locked 60 million people in their Wuhan homes on pain of death, but tens of thousands will have travelled in and out of the city in the weeks before the epidemic was identified. Those people went to Beijing and Shanghai – just like they traveled to Berlin and Milan and NY. Where are the other Chinese epicentres?

Dr. Chris Murray, the scientist building the US’s COVID-19 model today admitted in an interview that they don’t have a clue if it’s pollution or temperature, or culture, or lifestyle, or population health that is the key – mainly because none of these differ sufficiently between cities within the same country to explain the huge disparities in how the epidemic has played out.

This remains an open question that requires an answer if we are to be effective in managing the restart of our economies.