Are you more likely to be infected by a foreign worker?

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MOH said yesterday that only 1 in 5 of the new COVID 19 cases since May 4 – the start of the CMCO- involved Malaysians. Reading this simplistically, it means

• Have more CMCO as this will reduce the number of Malaysians getting COVID 19
• You are 5 times more likely to be infected by a foreigner than a Malaysian

OK, I am not being serious. But you have to wonder why it is not 5 times more likely to be infected by a foreign worker.

IT IS ONLY CORRECT if the foreign workers are well (and probably randomly) dispersed throughout the country. Statistically, it means that if you select a group of people randomly, the number of foreign workers in the group would in the proportion of foreign workers to Malaysians in the country. I guess it would be about 3 – 4 million foreign workers c/w 32 million Malaysians.

So if you have such a distributed sample, then I would say that you are 5 times more likely to be infected by contact with a foreign worker c/w contact with a Malaysian. But in reality, the foreigners are not dispersed throughout the country.

So, is there a way to gauge this foreign worker: Malaysian risk?

I think that most likely Malaysians would get infected by foreign workers as follows

• Staying with them (very few Malaysians expect for our maids)
• Working with them (good chance)
• Being served by them (good chance)

I think it is more correct to look at those cases where Malaysians have got COVID 19 by being in the same cluster. MOH doesn’t really report such statistics regularly but I picked up the following

• In the Detainee cluster, there are about 384 cases, with almost all foreigners. I read that so far there is one local infected

• In the Pedas factory where 219 total cases were reported since MOH did not provide a breakdown, my guess is less than 10% are Malaysians (based on May 9, MOH report that 7 were Malaysians out of 88 infected)

• Cleaning service company – all the 24 cases were foreigners

• 3 Construction clusters – of the 88 cases at 26 May, only 1 was a Malaysian

• Cheras Mall cluster – this is among the security guards with about 37 cases as of 26 May. So far I saw a report of 1 Malaysian

• Wet markets – this is the biggest cluster with 271 cases among the traders and workers. Residents in the surrounding areas of some of the markets were also tested. Again there is no breakdown from MOH but PJ market had 25% Malaysians

So are you more likely to be infected by coming into contact with a foreign worker as compared to contact with a Malaysia?

• Very very good chance if you are staying with them

• In the work environment, there is less than 3 % chance of getting infected by the foreign co-worker

• If your contact is with a foreign worker serving you, there is not enough data yet although going by the market cluster you probably have a 25% chance. We do need more info from MOH. The good news so far is that there is hardly any cluster from retail outlets. 

There is another piece of news for the past 2 days that we should all worry about. The day before yesterday, MOH announced this new cleaning company cluster with 24 cases. The cluster was detected when the company on its own initiative sent 150 of its foreign workers for testing, 128 of whom were found negative. Of the 24,

• 20 lived in a dorm in Kuala Langat while
• the remaining 4 shared an apartment in Nilai. 

MOH did its PUI testing for 428 people from close contacts and form residents in the areas concerned. I infer the following

• there are probably more cases from this cluster in the next few days as the test results come back,

• the 24 must be asymptomatic since MOH said that it was part of a test of all the workers

• More importantly, 24 people were infected about 2 weeks ago Since there was no mention of people being sick from these areas two weeks ago, it meant that the 24 caught it from either the asymptomatic or those who were sick and refused to seek treatment.

I guess it should as no surprise that there are many asymptomatic cases. MOH in its analysis of the Tahfiz cluster already concluded that over 85% are asymptomatic.

That is why I was surprised to see an article where researchers from several Australian universities studied the infections on a cruise ship and concluded that 81 % had no symptoms. The results we published in the "Thorax", one of the world’s leading respiratory medicine journal. A Professor Alan Symth, joint editor in chief on the Thorax commented that the findings also have implications for the easing of restrictions currently taking place around the world. If Prof had spoken to our DG of MOH, he would have found this out much earlier!!

We know we have asymptomatic cases walking about with the CMCO.

Since we are only doing targeted testing, I think the cluster-type reporting would be a feature in the coming months ie some group is going to be infected by an asymp


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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.