BR Research

Inadequate testing overestimates fatality risk

“Record” new cases are being reported every other day. The outbreak sure seems to have gathered pace as expected ear
Published May 12, 2020

“Record” new cases are being reported every other day. The outbreak sure seems to have gathered pace as expected earlier. Eyebrows are being raised on the timing of the lockdown easing. On the face of it, the daily reading of confirmed cases does make the decision to ease restrictions look untimely. More tests are being conducted every day than previous weeks.

And the pace of confirmed cases per test is also rising gradually. Around 7 percent of the tests conducted were returning positive a month ago. That number has now risen to 12 percent on weekly basis. Before one jumps to conclusions, experts warn that the number may be looked and interpreted in ways more than one.

A simpler explanation is that the outbreak is flexing its muscle and is spreading faster. This sounds plausible given the ground reality of the so-called lockdowns in large parts of the country. But bear in mind that Pakistan’s testing is nowhere close to be termed aggressive, or even sizeable to be sure of trends, as far as true infection rate determination is concerned.

Pakistan is conducting 1.17 tests per thousand people. Of countries with at least as many cases as Pakistan’s, only India, Indonesia and Mexico have tested fewer people per capita. On the scale of tests conducted, for every positive case Pakistan finds itself in company with the likes of Turkey, Italy, and Indonesia – all of whom have significantly higher death rates, with varying degree of testing.

The importance of testing cannot be undermined, and all efforts must continue to be put in testing maximum possible people to come closer to global testing average. It appears the government’s focus has shifted towards analyzing and strategizing around the fatality rate and risk. Media’s focus still seems to hover around the daily number of confirmed cases.

Pakistan’s Case Fatality Rate (CFR) is easily the lowest amongst all 25 countries with higher number of reported deaths. CFR is a very crude ratio and must not be confused with the actual risk of death which is the infection fatality rate and remains unknown. CFR in most cases overestimates the risk of death, more so in cases where testing is not high, such as Pakistan’s.

It is reasonable to assume that the number of total cases is significantly higher than number of confirmed cases, around the world, and more so in Pakistan’s case. It is common sense that when there are cases that are not counted properly, the probability of dying from that disease is lower than the reported CFR. Yes, there will be missed deaths too which are never counted, but the magnitude of deaths’ undercounting should always be lower than that for the cases.

That is where the fatality curve needs to be understood in greater detail in the media as well. It is after all the risk of dying that makes the disease what it is and not just testing positive with it. That is where extrapolating the CFR of 2.2 percent to the entire population and coming up with 1.4 million deaths is very misleading. Not only does it completely disregard the shortcoming of the CFR, it also pays no heed to peak of the curve. More on that tomorrow.

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