The Tricky Business Of Estimating A Reliable R0 Reproduction Number

I am not sure how many saw it, but MOH has finally released a chart of its virus model as shown below.  Reading off the chart, we have the following:

• R0 = 3.55 at the start of the MCO
• R0 = 1 if we have about 25 – 30 daily cases
• if we do not follow the SOP, the number of daily cases will be about 150 cases per day by mid-Jul.  The chart shows R0 = 1.6 but this value is flat from the last week of Jun.  I interpret this to mean that the model is projecting another MCO. 

I think that it is safe to assume that R0 = 1 in the model covers the situation where the daily cases are due to sporadic and/or community spread and not from those in quarantine and/or EMCO areas.  Accordingly, there will be about 40 daily sporadic/community spread cases when R0 first hit 1.6.  I think the model gives us a guide on when to start panic buying ahead of the crowd as another MCO is expected.!!

My estimates from community spread (ie total cases excluding returnees, clusters, EMCO) for the past few days are:  (refer to my posting of 8 May for the earlier days) Are we tracking the right things?

Date            Community spread

                    No of daily cases

9 May                3                  

10 May              8                    

11 May              25                   

12 May             13                    

13 May             10                  

The statistics above showed that the average number of daily cases is about half of that for R0 = 1.  Since the period covers the CMCO, it does indicate that we are not likely to see any exponential growth.  

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OP TCF posted some articles about Sweden’s strategy for Covid 19 that was based on voluntary social distancing rather than national lockdown.  The under-reported thing about Sweden was that it managed to keep the virus spread within the capacity of its medical system.  I am sure that if it had exceeded this, it would have declared a national lockdown. 

There are two challenges for any country trying to copy Sweden ie

• Do you have the medical capacity?
• Do you have a population that can voluntarily social distance and observe other public health measures?

While Malaysia has high enough medical capacity, we cannot meet the population requirement.  Just think of how difficult it would have been to stop the Sri Petaling event and think of the millions of foreign workers who are not able to social distance.

I happen to think that we have the right strategy today ie have the CMCO with the ban on public gathering and have the MCO as a contingency.  Then whenever a cluster arises, MOH can act accordingly ie

• for location-based clusters, EMCO those areas which show a virus surge
• for event-based clusters and others, contact tracing and isolating PUI.  

Our shortcomings are the lack of random testing and not making wearing masks mandatory.  If there was a mistake, it was that we should have phased into the CMCO weeks earlier.  

As for the economic impact of the MCO, there are 2 things I don’t quite understand

• Given that exports account for about ¾ of the country’s GDP, wouldn’t we have an economic slowdown even if there was no MCO?  The low oil price, the low palm oil demand, the low demand from importing nations have nothing to do with our MCO. I think the new normal would be 1 to 2 years of hardship.  

• During his 4 May announcement, our PM said that about 45 % of the workforce has gone back to work under the CMCO.  I cannot reconcile the balance 55% as most of those which cannot operate under the CMCO is from the education sector, leisure, hawker type businesses and of course the barbers and saloons. They cannot account for the balance of about 8 to 9 million workforce. 

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PS: This blog is for me to better understand COVID 19 as this will impact my investments. If you are also into equities, follow me at i4value.asia

Disclaimer:  I am not an epidemiologist, healthcare worker, pharmacist or staff in the Ministry of Health, but rather is someone with a strong interest in numerical analysis.  The content is an attempt to understand what is happening in the battle against Covid 19 from a data-based perspective. The opinions expressed here are based on information extracted from readily available public sources but I do not warrant its completeness or accuracy and should not be relied on as such.