C-19: Locking down at 11th hour before much anticipated public holiday was an ill-informed strategy

Updated: May 11

We review the data of daily cases against mobility changes (measured by Google Community Mobility reports) for Malaysia since the start of the pandemic, and attempt to make the case that the latest debacle arising from the upcoming MCO#3 lockdown orders stems from an ill-calculated strategy that could have been easily avoided had we used scientific analysis to understand the bahaviour of the pandemic under different mobility scenarios.


(A) Mobility and dwell-time are almost entirely what drive transmission of COVID-19


Our daily reports across multiple countries show clearly how mobility changes day on day have driven changes in transmission of COVID-19. While the method is fairly crude in that aggregated country data is utilised, the correlative fit has proven to be a robust method to determine case trajectories in almost all countries.


Note: Google Community Mobility does not measure mobility or movement in the usual sense of the definition, but rather the deviations in size of crowds and their dwell time at a particular location.


(B) There is a clear lack of comprehension in the time lag between reported case detection and deaths vs. initial infection


It takes days before one even considers taking a PCR COVID-19 test, mostly due to cost but also the discomfort of nasal swabs. PCR tests are the most sensitive and can detect the presence of the virus even at the pre-symptomatic and pre-infectious phases. However, more often than not the test is taken only after one shows symptoms. Add to this the test processing time and reporting time lag, and there is thus an expected delay between the time of infection and when the test results tallied via daily reports. For Malaysia, we measure this delay to be around 14-17 days. This fairly simple concept seems to be lost on those making key decisions on movement controls. Daily cases are somehow expected to move drastically on daily movement control orders - an absurd expectation if one appreciates the real facts.


(C) Every public holiday over the past year has reduced mobility and therefore transmission


The data speaks for itself - see figures below. Every public holiday has reduced mobility and therefore transmission. No amount of daily visitation to relatives and among family members can be expected to outpace the movement of a full working day, where workers are at the office, public transport is on full tilt, and retail locations are bustling with workers transitting to and from the office.


(D) We had a choice to lockdown earlier, and recover in time to celebrate a much anticipated day with our loved ones


If we understood the science better, then we could in fact have reduced movement through moderate control orders two weeks ago at the end of April. This would have thus tapered cases enough by the eve of Aidilfitri (given the ~2 week case detection delay), so we could all have enjoyed the holiday in peace together with our loved ones. Alas, that choice is now behind us.


(E) This celebration would have given a much needed morale booster to the nation


We had all been anticipating the welcomed respite and normalcy that would have been afforded by two days of Aidilfitri break. Morale among the population is at an all time low given the havoc wreaked on the economy by the pandemic; and unfortunately so is public confidence in the government machinery. This should have been a chance for those in power to redeem their positions had they acted with foresight and by using facts, in addition to communicating well throughout the decision making process. Alas, that choice too is behind them.


Refer to following figures for supporting information.


Disclaimer:

It bears noting that we are not advocating a total free for all interaction during the Aidilfitri break. Merely that some limited interaction and visitation could in fact have been permitted on balance given the distressing time all of us are enduring, and the deep meaning the day carries for most Malaysians.


Figure i: overall daily cases plotted in log Y-axis since March 2020; shows variation of cases since start of the pandemic. Note the deviation between actual cases (in blue) and the mobility driven case trajectory (in yellow) is only apparent for daily cases <100, and is likely due to daily reporting variations and high error variance at these low volumes. Also, case detection delay has trended upwards - in early peak in March 2020 the delay was ~14 days vs. now ~17 days hence the overlap between the two curves shows deviation at this earlier date.

Figure ii: daily mobility changes against MCO (Movement Control Order) dates [in black] and public holidays [in blue]. The 'composite mobility' [in light green] generates the case trajectory [in yellow] in the previous figure. Public holidays clearly drive down mobility as evidenced by spikes downwards (refer to work mobility for clearest depiction); MCOs are by far the stronger driver of mobility reduction.

Figure iii: daily cases in Malaysia since September 2020. Case trajectories are expected to peak around 25 May, in spite of lockdown on 6-7 May, due to case detection delay. It should be noted that this is likely the 'optimistic case', it is more likely that actual mobility changes have not been as drastic given isolated the MCO implementation was done in isolated geographies and not nationwide (expected nationwide implementation on 12 May).

Figure iv: daily mobility trajectory since September 2020. An aggressive lockdown has been assumed to occur under MCO#3 starting ~7 May 2021, resulting in the case trajectory line [in yellow] in figure above.



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