Toying with herd immunity

It is worth asking how prepared we are to follow standard safety guidelines

The number of confirmed cases of coronavirus infection in Pakistan has reached nearly 50,000 as of May 21. The number of people dying of the disease is already over 1,000. Pakistan only recently came out of the lockdown partly under pressure from the business community, and partly as a result of the government’s expressed concern for the livelihoods of the poor.

The government may have its plans for a “smart” unlocking of the economy. Still, the chief justice of Pakistan ordered the reopening of the economy “seven days a week” and forced the government to re-open shopping malls. The federal government welcomed the SC orders.

The government has followed an ambivalent policy towards lockdown. While it let the provincial governments be in the driving seat, in line with its constitutional duty, it continued to cast doubts on the efficacy of the lockdown policy. At one point, the prime minister went so far as to suggest that the policy was adopted under pressure from the “elite.”

Pakistan had been facing an economic downturn even before the Covid-19 crisis. The coronavirus pandemic only precipitated the downhill journey. Foreign aid, which was eagerly awaited in normal times, is being desperately requested in the current crisis. However, only a fraction of the humanitarian aid is being promised by multilateral agencies.

Faced with the double jeopardy of a blging population and a woefully lacking healthcare system and dire economic straits predating the current crisis, is the federal government considering relying on herd immunity to take care of the existential problem of Covid-19? There have been only mixed signals from those in charge.

Special Assistant to the Prime Minister Dr Zafar Mirza has conceded that “it will be better for the future if coronavirus spreads at a certain level so that people can become immune to it. Next, Federal Minister Asad Umar suggested in a talk show that the logical conclusion of the pandemic is either a vaccine or a situation where 70pc of the population contracts the virus and achieves herd immunity.

On another occasion, Dr Zafar Mirza categorically rejected the suggestion that the government was considering relying on herd immunity. He went on to say that the government was neither promoting a herd immunity approach nor discussing it. Minister for Science and Technology Fawad Chaudhry, however, spilled some beans when he stated that experts in his ministry had discussed the idea of herd immunity and concluded that it was a risky and dangerous policy prescription.

Given the grave risks involved in following the policy of herd immunity, it is crucial to have a clear understanding of the concept of herd immunity, and its pros and cons in Pakistan’s context. The basic idea of herd immunity is that when most of a population is immune to an infectious disease, this provides indirect protection—or herd immunity (also called herd protection to even those who are not immune to the disease.

For example, if 80 percent of a population is immune to a virus, four out of every five people who encounter someone with the disease won’t get sick (and won’t transmit the disease any further). In this way, the spread of disease is never exponential. Depending on how contagious an infection is, usually, 70 percent to 90 percent of a population needs immunity to achieve herd immunity. Based on early estimates of this virus’s infectiousness, we will likely need at least 70 percent of the population to be immune to have herd protection for the rest.

Given the grave risks involved in following the policy of herd immunity, it is crucial to have a clear understanding of the concept of herd immunity, and its pros and cons in Pakistan’s context.

Sweden has become a veritable case study of herd immunity in the ongoing coronavirus pandemic. While it asked its citizens to practice social distancing, it explicitly followed the policy of herd immunity. The result is that nearly 60 percent of the people in Stockholm are reportedly infected.

The architect of Swedish Response to Covid-19, Professor Johan Giesecke, believes that the correct policy is to protect the old and the frail only, which will eventually lead to herd immunity as a “by-product.” Prof Giesecke defends the Swedish strategy as the “best in the world” because he believes that by enforcing lockdowns, “you’re pushing your cases and deaths into the future, they are not disappearing.”

But the apparent simplicity of the Scandanavian nation going against the tide may be deceptive. Even if Sweden did not declare a lockdown, it did ask its citizens to practise social distancing. It has restricted public gatherings of more than 50 people and has issued guidelines for academic institutions.

The analysis of how successful Swedish policy is must start with the express purpose of the policy. What may come to many as a big surprise, the purpose of following herd immunity policy is not to reduce mortality.

Prof Giesecke believes that although Sweden has suffered more deaths than its neighbors when the death toll is counted a year from now, it will not be much worse, but the economic impact will be less severe. So herd immunity policy is essentially about the economics.

A disproportionately higher death toll in Sweden has nonetheless put the authorities in hot water. Feeling the public pressure, the authorities in Sweden have taken a series of U-turns. The government seem to be for herd immunity strategy, then against it, then for it again if the data look promising.

More worrying than the government’s embarrassment is the evidence that the policy of herd immunity may not after all be working as expected. A Swedish study found that just 7.3 percent of Stockholmers had developed Covid-19 antibodies by late April, which could fuel concern that a decision not to lock down Sweden against the pandemic may bring little herd immunity in the near future.

An implication of this study is that a high infection rate - in the 70 to 90 percent bracket - with very few people having developed the immunity could be a recipe for an unmitigated disaster.

Many experts find the idea of herd immunity fraught with dangers. Herd immunity without a vaccine is, by definition, not a preventative measure. Mike Ryan, WHO’s executive director of health emergencies, believes that talking about the risks to human life in probabilistic terms is brutal arithmetic, which does not “put people and life and suffering at the centre of that equation.”

Looking at the policy of herd immunity from the perspective of mortality rates may be far more revealing. Currently, the fatality rate from Covid-19 is around two percent in Pakistan and around the world. Experts have projected several mortality rate scenarios to inform public policy.

So far, the most optimistic scenario is that the Covid-19 fatality rate will stabilize around 0.5 to 1 percent. If 70 percent of an entire population gets sick, that means that between 0.35-0.7 percent population of the country could die. Using Pakistan’s baseline population of 220 million as a benchmark, even the best-case scenario may result in somewhere between 539,000 to 1,078,000 fatalities.

Pakistan‘s economic vulnerabilities, accentuated by the expanding scope of locust attack, do not allow it to remain under lockdown for an indefinite time. However, there is no gainsaying the fact that following a strict safety regimen at the individual level is our best hedge against the worst-case scenarios.

It is worth asking how prepared we are to follow standard safety guidelines. Even if there is reason to believe that there were severe loopholes in the implementation of the lockdown in the first place, the madding crowd of people thronging markets for Eid shopping was a sobering spectacle. While Islam’s two holiest places are partially shut down because of a global pandemic, one wonders what the logic behind the arm-twisting by the clergy in Pakistan to open mosques for prayer and hold mourning processions was. The authorities buckling under the popular pressure owe an answer to this question because they were expected to know the proclivity of many Pakistanis to take serious things lightly and light things seriously.

The writer is an Assistant Professor in the Department of Economics at COMSATS University Islamabad, Lahore Campus

Toying with herd immunity