Link between population size and Covid-19

What has worked elsewhere may not work in Pakistan

Eased lockdown in Karachi. PHOTO: REUTERS

Ever since the advent of the Covid-19 pandemic in Pakistan, the media, politicians, and policymakers have been discussing and debating our epidemic control strategies. Should we go for a complete or smart lockdown? Or should we impose a curfew or gradually relax the existing partial lockdown? Ostensibly, economics and the number of emerging cases are the two major considerations influencing our decisions. But we hope that at this critical time, these decisions are also guided by science, specifically what epidemiologists refer to as the reproduction number or “R naught” (R0).

R0 is the average number of people to whom an infected individual can expect to transmit the infection. An R0 of 1 would mean that, on average, an infected person will transmit the infection to one susceptible person. All epidemic control efforts are directed to bringing the number below 1, and in Europe, it is this number that has primarily guided lockdown-related decisions.

Interestingly, R0 is not only affected by biological factors such as the pathogenicity of the organism but also — and more so — by environmental and socio-behavioural factors. Transmissibility is closely linked to the demographics, of a country that includes its population size and density, average household size, the composition of the population, its age structure and life expectancy. Behaviours such as practising social distancing and staying at home, on the other hand, are influenced by literacy levels while socio-economics affects people’s living conditions, mobility, health-seeking behaviours, ability to access healthcare services and nutritional status. While the environmental factors that have a bearing include access to and availability of clean potable water and air quality. All these factors influence individual susceptibility to the infection.

Keeping in view Pakistan’s demographics and socio-behavioural attributes, our planners will need to focus on an indigenous model for lowering the R0 and controlling the epidemic. What has worked elsewhere may not work in Pakistan. For instance, the sheer size of our population makes large-scale testing, a strategy being followed in most developed countries, difficult. Home isolation, another strategy that is being advocated, will be hard to implement when most of our people live in cramped conditions.


For decades, demographers, public health practitioners, and civil society activists have been imploring governments to take concrete steps to lower our population growth rate as the unbridled increase in numbers is incompatible with our efforts to conserve resources and achieve development targets. Economists were repeatedly informed that among 60 million of our poor people, large families are not a choice but a consequence of unwanted pregnancies resulting from lack of access to services, and that a reduction in family size would result in savings that might buffer poor households during crises. Had we heeded this advice, we would not have such a large illiterate population dependent upon daily-wage employment, or been forced to factor its huge economic vulnerability in our epidemic control efforts.

The present pandemic will eventually peak and abate but our vulnerabilities to communicable diseases will persist due to our large population base. And this is why the battle against Covid-19 should not distract us from our efforts to stabilise our population growth rate. At this critical time we must ensure that women’s reproductive health especially family planning needs are not compromised. We should continue to implement in an unabated manner the decisions of the Council of Common Interest (CCI) on lowering our population growth with the Federal and Provincial Population task forces providing regular oversight. It is the only way to build long-term resilience and ensure our people are protected from the ravages of future epidemics.

Published in The Express Tribune, May 14th, 2020.

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