The Second Wave

From the chart below we can see that cases in the UK have been rising for the last five weeks. This is also true of France and Italy,  Germany’s cases have only risen in the last two weeks and Australia’s has reduced.

 

It appears that the rate of increase is reducing in the UK, and this may be due to recent restrictions (the rule of 6) or the test and trace system being saturated.
If we look at the corresponding death rates we can see that the death rate in the UK has been rising for 3 weeks. Germany’s death rate is fairly constant and Australia, who is coming out of a second wave is reducing steeply.

 

As Australia seem to be coming out of a second wave (as they come out of winter!), it is interesting to examine this more closely

 There is a very obvious three week delay before changes in the infections appear as corresponding changes of deaths.  (The spike on 6th September is probably due to a delay in recording the data.)
Australia was trying it’s best to combat a rise and Melbourne began to lock down on 20th June. Cases had risen to around 30 per week per million of population. Lock downs were initially in particular areas. Tighter and more extensive restrictions were applied as cases continued to multiply.  The peak occurred at the beginning of August when the actual number of cases were around 1,400 per week per million. 
As the measures took effect the cases came down, but the death rate was three weeks behind and peaked at around 40 per week per million.
Cases are coming down and are now close to before the wave. Deaths are three weeks behind and currently at 100 per week per million.

Comparison with the UK’s current situation.
Australia’s testing regime was focused on the problem areas and therefore the “hit rate” was much higher than the UK. Case to deaths (after three weeks) ratio was about 24. 4% of the people who were infected died. As the mortality is higher for the old and vulnerable this 
The UK’s is currently 58.  Three weeks ago it was 158! So it is not valid to use the test data to map across to the predicted deaths without adjustment.
Basically, as the testing become more focused on the areas more likely to be spreading the virus, we will get less negative results and therefor more positive results.

Delays
Consider a suddenly applied lockdown which is 100% efficient. The day after lockdown, cases will continue to rise as those infected before the lockdown start exhibiting symptoms. Cases will rise still further as they will be infecting their family or “bubble”. This process could take a matter of a few weeks.
But cases should drop as no further infections from these bubbles should occur. But the death rate is about 3 weeks behind the infection rate so we would not expect to see a change in death rates due to changes in restrictions till around 5-6 weeks after the restriction is applied.

Deaths are currently at about 22 per day and are doubling every week. The effect of “the rule of 6” is yet to be seen. If the new restrictions do not have an effect for 5-6 weeks then deaths will reach over 1000 per day by the end of October. Most of these will be over 50.

The data from Australia of 26,814 cases and 704 deaths starkly indicates this.

 

All of the deaths occurred in the over 50s,

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