Covid-19: what is wrong with random testing?
The writers an Adjunct Professor of Epidemiology at the University of Nebraska and has worked for the US Center for Disease Control and Prevention. lie can be reached at jasgharOgmaiLcom
pakistan is relaxing its lockdown. According to global public health experts, a relaxation in lockdown should only be extended with en-hanced contact tracing and testing to ensure there is no sudden rise of cases. Pakistan's declared strategy to control Covld-19 is "Tracing, Testing and Qurantine (QTT)". The government declared it would like to do 20,000 to 30t000 tests per day to make this work. However, we are struggling with 10,000-12,000 tests daily. Reasons for this include lack of testing kits, transport medium, and suspect refusals to get tested in the face of social stigma. To increase testing numbers, random testing is being advocated in Pakistan. The argument is that until now we have focused on high-risk travelers and their contacts or those with symptoms. With random testing we will have a clearer picture. Unfortunately this is not only advocated by non-technical politi-cal leaders, TV anchors but also by
armchair epidemiologists, There is no denying that our dismal test-ing rate is a major impediment to control this outbreak. However, random testing will also not help in this regard. Random sampling and testing has a precise methodology to it. If done properly it is the most suitable Method to know the prevalence of disease by testing a few people. But for that we need to list everyone living in a geographical area, then randomise everyone in that area and pick the number we need to test. Nov think about making a list of everyone in Lahore or Karachi. Randomising the list and picking the number selected by a computer and then finding those people. But that is not what advocates are think-ing. They are thinking about going to an area and testing few people there. That is a convenience sample. So what difference does it make? A lot! Where a true random testing will give you excellent information, convenience sample will give you
nothing. This type of convenience testing will be a waste of resources with no meaningibl insight on the Covid-19 outbreak in Pakistan. Instead, we need to enhance con-tact tracing of known cases i.e. get-ting information of all the possible contacts of a Covid-positive person in the last Di days. Family members are not the only contacts. This Means you need to train your staff to do it right. Globally, this is being considered a critical step in combat-ting the disease. Unfortunately, ex-cept for Pakistan Field Epidemiology and Laboratory Training Program (FELTP) graduates, no one knows how to do it properly here as it's not taught in medical or public health colleges. But my concern is that even though this is pan of our strategy we have not understood what it takes to do it properly at the Senior decision-maker level. With increasing cases, we need to hire and train new staff for just contact tracing and existing FELTP staff could act as master trainers. China
raised a =all aunty for this. In New York alone a Mo million project was started to hire additional contact tracers as contact tracing is a serious skill and needs to be taught. Secondly, we need to extend test-ing to our high-risk groups i.e. doctors, nurses and all staff working in healthcare settings, police and law enforcing departments in field duties, etc. However, if we want to know how common Covid-ig is in communities then the current PCR test is not light test because it only tells us a current acute infection, For community prevalence, anti-body tests tell us if the person has been recovered from coronavirus in the past. While the validity of these tests are doubtful, the world is hop-ing to get these tests to find the ex-tent of the problem as 3o% patients are asymptomatic. However, these tests also need to be deployed in a scientific manner to be fruitful, We must reach out to epidemiologists to design a deployment plan for test-ing as COVid-19 is a serious matter.
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