Diagnostic testing and Covid-19

The true nemesis of all pandemics is diagnostic testing. This, indeed, is the gospel truth! Covid-19 is no exception. Testing is the most uncomplicated, remarkable and efficient mechanism medical specialists and epidemiologists could employ to devise a response against the formidable but devious pandemic. Apparently, the most brilliantly conceived and all-embracing plan to combat the SARS-CoV-2 virus will not work unless driven by an extensive, astutely executed and properly targeted testing regime.

Pakistan has oddly not opted for mass-scale testing for Covid-19 despite the fact that experts have referred to diagnostic testing, isolation and contact tracing as the three pillars of any robust public health response to the eruption of the disease. The dazzling triumph of this model could be observed in South Korea (population density: 527/km2) where it considerably brought down the death rate without any Gestapo-like lockdowns and stringent quarantines. South Korea fashioned this marvel primarily by testing around 20,000 people a day at 600 testing sites.

Why is diagnostic testing so important? Pandemics are essentially triggered when continuous chains of transmission are available to the pathogens involved. The pathogens need these open and accessible chains to infect hosts and replicate swiftly. This creates a natural domino effect which depends upon the type of hosts and their collective immunological potency. However, the invisible labyrinths of these transmission chains cannot be observed and consequently an across-the-board remedial approach cannot be conceived until pathogenic routes are explicitly established and clusters of the infected hosts are made visible through diagnostic testing on a considerably large scale.

Tests can also reveal four key facts about the population being tested: one, the number of people who are infected; two, the number of people who are mildly infected; three, the number of people who are infected but are asymptomatic; and, four, the number of people who are not infected. In this particular way, the invisible infections create a jigsaw puzzle of sorts within a population which can only be discovered if extensive testing is done and its results are carefully assessed and collated. Frighteningly, the evidence reported in several studies has revealed that almost half of the transmissions are caused by asymptomatic carriers. Testing can, resultantly, be used to isolate both the infected and the carriers and save the uninfected. It can also reveal the total number of infections and the speed with which they are spreading.

Within this giant jigsaw puzzle, certain flashpoints of intense pathogen activity with a large number of infected are invariably present. When infected people living within these flashpoints throng public health facilities, the authorities become suddenly aware of the existence of these dangerous points. This nightmarish scenario can overwhelm hospitals and make the medical experts’ response less effective due to the paucity of time and lack of preparation. Testing, however, can make the health authorities aware of these flashpoints and elaborate plans regarding the suppression of the pandemic can be formulated. Likewise, quarantine protocols and self-isolation SOPs can be enforced at these flashpoints to lessen their potent pathogenic impact.

Since diagnostic testing can reveal the precise number of the infected and pinpoint the flashpoints where the infections are burgeoning, health officials can take decisions based on solid data rather than mere conjectures. Decisions like increasing the capacity of the existing hospitals, building new ones, creating quarantine facilities, purchase of PPE for medical personnel and getting necessary equipment for patients should be based on pure facts as they impinge heavily upon a government’s capacity to fight the pandemic.

It is high time Pakistan resorted to mass scale diagnostic testing. This should be done through hospital labs, mobile labs and house visits to test as many people as possible.

Published in The Express Tribune, April 8^th, 2020.

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