By Ajmal Khan Yousafzai
Those struggling to find reasons for the dramatic turnaround of events to Pakistan’s coronavirus infection rate, may find something close to what could be called a reason, in the recently written research paper by doctors at Karachi’s National Institute of Blood Diseases (NIBD), released by the Oxford University Press Journal of Public Health. And all roads lead to that once mocked words, “herd immunity.â€
Recall that the government back in May 2020 had suggested taking the herd immunity route. It never became official, but the two key-most figures at the helm of affairs in the response to the coronavirus, Asad Umar and Dr. Zafar Mirza had at various stages hinted at letting the virus spread to a certain level so as to allow people develop immunity. The notion was ridiculed by a section of society, and was labelled as “unacceptable†, “inhumane†and a result of “deep lack of understanding of the issue†.
Not that the critics have been proven wrong already. Not just yet. But the longer Pakistan keeps the infection rate within acceptable ranges of “spread under control†as defined by the WHO, the more herd immunity will become the only justification for the turnaround. And now it has some research backing by the doctors, in the research paper titled “Seroprevalence of anti-SARS-CoV-2 antibodies in resident of Karachi.â€
The study was conducted between May and July, which carries significance in the understanding of events. The sample size of 1675 constituted of 48 percent industrial workers, 28 percent healthcare workers, and 24 percent community population. Healthcare workers showed the lowest seroprevalence of antibodies at 13 percent. The community (general) population showed 34 percent positivity, whereas the industrial workers returned a mind-boggling 50 percent positive rate.
This may not be the truest reflection of the city’s demographics, but in a situation where lockdown is lifted and social distancing is hardly practiced, human interaction is high across groups. The healthcare workers selected for this study were not hospital workers directly exposed to coronavirus patients, and generally take more precautionary measures than common people, which explains slightly lower seropositivity rate.
Recall that almost 95 percent of cases in Pakistan have been found asymptomatic. An earlier study by Getz Pharma in May 2020 had shown a seroprevalence of 8 percent amongst its employees. That was a mix of healthcare and industrial workers. Compare that with 36 percent seropositivity for the NIBD research – which was conducted in the two months following the Getz Pharma research, and you see a trend.
Plot the numbers against the steep rise and then a dramatic decline and a rather encouragingly long flattening of the curve at under 3 percent of infection rate, and you would find yourself in agreement with the study’s finding that two months further on, the seropositivity could well have increased from 36 percent to 60 percent. And 60-70 percent is what is needed to gain herd immunity.
That said, this should not become a reason for lowering the guard. Testing has also increased in the last week or so, which is encouraging and more days of high testing with continuation of lower infection rate, in an economy that is completely open, will further strengthen the herd immunity notion, and more importantly will reduce chances of the much dreaded second wave, which has engulfed most of Europe.
