These findings are shared for research purposes and indications for decision makers to help them broaden perspectives and expand understanding until they materialize in a reviewed paper.

Lockdown policies

Studying data from Project for European Mortality Monitoring in Denmark it appears if we assume that overmortality peak was caused by Covid and not lockdown that some countries were caught of guard by a virus that is mild enough to be invisible with a changing R value, a fairly long incumbation period,  accelerating suddenly and taking its course.

In such countries Spain, Italy, France, Belgium, UK, Netherlands, Switzerland, Sweden and possibly Portugal, Malta and Greece had peaked before  any people’s lockdown took place. 

We classified lockdowns into 7 major groups

1- Stop large gatherings, encourage social distancing --→ Sweden

2- Places lockdown =Shut closed places of gatherings, separate regions and strongly encourage working from home (restaurants,  -----→ Switzerland, Germany, Denmark, Finland, Malta, Greece, Austria, Ireland, Netherlands, Australia, New Zealand)

3- Peoples’ lockdown = Places lockdown + Shut down parks + Restrict peoples’ movements within the city to absolute necessity under police control –-→ Italy, Spain, France, Belgium, UK

4- Night lockdown = Mild places lockdown + Allow movements in daytime, restrict them at night (Senegal, Algeria, Egypt….)

5- Full contact tracing = South Korea, Taiwan, Singapore

6- 3Cs lockdown = Instruct population to avoid Closed spaces, Crowded places, close Contact settings –→ Japan)

7- Different policies across a same country Mostly large Federal countries –→ USA, Brazil,China...

 

 

Understanding how much of its natural course the virus had, gives insight as to how much collective immunity was acquired in a particular context. To understand such course a few sample countries were analyzed working backwards from mortality peak to probable infection date.

Given that the median delay between infection and death lies between 21 days and 25 days (5.1 days incumbation to symptoms and 17.8 days symptoms to death). That places infection peak  week 11 that is March 9 to March 15th before lockdown of people happenned and after lockdown of cluster risk places had taken place. Locking down non essential clustering places may have been sufficient to reverse the curve that started becoming agressive  around week 8 to 9. For at least 12 weeks the epidemic was moving at a very slow pace becoming very aggressive when conditions are united.

 

https://www.acpjournals.org/doi/10.7326/M20-0504

https://www.acc.org/latest-in-cardiology/journal-scans/2020/05/11/15/18/the-incubation-period-of-coronavirus-disease

 

« The median incubation period was estimated to be 5.1 days (95% CI, 4.5 to 5.8 days) »

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7014672/

«  we estimate the mean incubation period to be 6.4 days (95% credible interval: 5.6–7.7) »

 

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30243-7/fulltext

« we estimated the mean duration from onset of symptoms to death to be 17·8 days (95% credible interval [CrI] 16·9–19·2) »

 

Above studies are further confirmed by the fact that using google’s mobility data we found as mentionned above for countries with high death count that correlation between daily ridership and death count was highest at 25 days lag.

 

We checked EuroMomo’s data and dates by comparing their curves with data extracted from INSEE in France and Statbel in Belgium to find them consistent with EuroMoMo’s data.

We traced back with a fairly reasonable degree of confidence infection peak  time for countries by placing it 3 weeks before overmortality peak to evaluate how much of its natural course the disease had in different countries.

 

 

 

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Most peoples’ lockdown happenned concurrently or after peak had happenned and curve had turned around.

Belgium had hit a plateau of 83 deaths on April 4th with consecutively 70, 75 and 86 to start a drop as off April 8th, placing probable peak and turnaround infection period around March 16th. That places turnaround right after places lockdown and before peoples’ lockdown.  

France hit its plateau of overmortality April 1st which places probable peak and turnaround around March 12th and March 14th after large gatherings ban, right before places lockdown and and 4 days before peoples’ lockdown. This seems to apply to Belgium, France, Italy and UK.

Places lockdown intervened in some cases before places lockdown, in some cases after and in some cases concurrently with no clear trend as to outcome in terms of mortality.

Countries recurring to peoples’ lockdown did so as they were heading towards a high price to pay and at the time of the decision had no knowledge as to where they were in the curve except for epidemic models, most of which turned out to be faulty. They could have started to understand around April 10th seeing consecutive days in mortality drops and relying on available studies from far east as to what measures may have contibutes to such turnaround in the curve.

Also there is no clear tendency, as to lockdown duration and severity.

Most countries that locked down early have avoided a severe peak, but again Greece, Protugal, Malta and Switzerland locked down late and had a mild epidemic.

From above data, it seems reasonable to assume that epidemic followed much of its natural course in at least 17 of 21 countries mentionned.

This is further confirmed by the absence of rebounds anywhere except for localized clusters in locations/populations that had not been exposed.

This calls for attention as some regions may see their population density and composition change.

Otherwise regions that were exposed and where epidemic took its course benefit of a fair level protection under spring summer conditions with some risk of occasional clusters but limited risk of a full national epidemic.

Looking at a different part of the world, Japan has had no lockdown, has performed relatively few tests (less that most European countries), has very dense cities and one of the oldest world populations, yet it has suffered a very mild epidemic that did not seem to rebound. Japan simply instructed its population very early on to avoid Closed places, large Crowded places, and unecessary physical Contacts with strangers as a policy that could be applied on the long run. Could it have been sufficient ? Maybe their diet and  excellent heatlh helped.

Tadjikistan has had no lockdown and 6 deaths per million compared to Kazakstan 20 deaths per million.

Japan fairs with 8 deaths per million people, UK 650, Spain 607, Italy 567, USA 399, Germany 52, Norway 46.