When we first went into MCO, I used to get data on the number of tests carried out from the MOH website. Then sometime in early April, MOH stopped reporting such info so I switched to Worldodometer. But since 11 May, the number of cum tests for Malaysia as reported by Worldodometer remained unchanged. I went to a few other sites to check and found that Malaysian data were available only till 11 May. Does anyone know what is happening?
According to MOH, we now have the capacity for 26,000 tests per day and considering that the number of patients under treatment has reduced significantly (ie thereby reducing the cases required for re-testing), there ought to be a significant increase in the number of new cases being tested daily.
For those who missed the news, MOH has a targeted testing programme that is currently focussed on 8 groups. The OPs belong to one group. The targeted groups are
- Tabligh - 38,700 tested so far
- Tahfiz - 12,800 tested so far out of 20,000 students and teachers.
- EMCO areas
- markets - I think the focus is those in Klang Valley
- senior citizens - I am waiting to be tested
- foreign workers - 24,000 tested so far
- healthcare workers - 6,800 testes as at end April
- existing clusters
The other interesting news is that 85 % of the Tahfiz positive cases were asymptomatic. MOH did not provide that age profile, but I wouldn't be surprised if this is because the majority of the students are young. I wish MOH would provide more info. I am sure that it cannot be due to religious beliefs or the school location.
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According to Datuk Dr. Amar Singh, a senior consultant pediatrician, we have thousands of mild and/or asymptomatic cases in the country.
However, I estimate that the numbers are in the low hundreds.
We will know who is correct come Raya – a surge to > 100 daily cases means that all my analysis is wrong and I should really stop doing anything further. OK he is a doctor and I am just an engineer, but let me argue my case.
Star had an article yesterday quoting Datuk Dr. Amar as saying that it was reasonable to assume at least 0.1 % of the population is Covid 19 positive i.e. 32,000 cases many of which are mild or asymptomatic and warned about a spike in cases as we now have more people moving about.
Datuk Dr. Amar had previously estimated the number of infections using the backward-looking mortality method so I presumed that the 32,000 cases are similarly derived. He had said previously that the number of cases in the country is higher than that reported by MOH. I happen to agree that we have higher numbers than those stated by MOH although I don’t think it is as high as 32.000 cases.
But even if we accept that there are 32,000 cases, we cannot conclude that all of them are still sick. Over the past 3 months, many would have recovered so if we use the same recovery rate as those reported by MOH, then we should only have about 20% of the 32,000 still sick i.e. about 6,400 cases.
If indeed we have 6,400 mild or asymptomatic cases walking about and assuming R0 = 1 i.e. one person infecting 1 other, then we should be having 6,400 cases over a 2 week period (average duration of sickness) equivalent to 457 daily cases. Since we don’t have such figures either over the past 2 weeks or even the coming 2 weeks, I think the 32,000 cases must be wrong.
I will now try to reconcile the potential mild and asymptomatic cases with the actual numbers that were infected. If we assume that all the new clusters and cases (excluding the returnees) since the start of CMCO we caused by contacts with mild or asymptomatic cases, we have
- Total cases since 4 May not due to returnees or old clusters = 393 (Note 1)
- Assume R0 = 1 to 1.6
- Computed mild or asymptomatic cases = 246 to 393 people
OK, while this is a simplistic analysis I think it does provide an order of magnitude of the potential number of mild or asymptomatic cases.
So over the next 2 weeks we should monitor the number of cases that are not due to contacts with old clusters and/or with those in the EMCO areas. We can assume that such cases are due to contacts with mild or asymptomatic cases. We can then work backward to derive the number of mild and/or asymptomatic cases. I am confident that it would be closer to my estimates than those by Datuk Dr. Amar Singh.
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OP JM posted the link to an Australian article that had a number of charts tracking how Covid 19 is spreading around the world. When it came to testing, to get around the situation where less testing meant fewer cases detected, it charted the cum number of tests per cum confirmed cases. An upward slowing line meant good performance.
I reproduced the chart below where the black and purple lines are for Australia and South Korea respectively. The bottom 2 lines are for the US and UK.
I have not seen such an analysis before so I decided to see whether Malaysia is in the Australia/South Korea category or in the US/UK category. The chart for Malaysia is shown below with numbers about the same as those for South Korea. I am glad that we are in the former group as it means less chance of exponential growth as we enter into the CMCO phase.
Note 1 : Computation of total cases from new clusters since the start of CMCO
Chow Kit market = 82
Cheras ma = 13
Pedas = 151
PJ Old Town = 27
Community = 120
Total = 393
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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.
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