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Lockdown Vs herd immunity

Date : 2020-Oct-20
There is, at present, a scientific debate on the relative merit of lockdown and herd immunity in the management of Covid-19 with substantial amount of good research going on. However there is no consensus among top researchers on this matter. They still do not say in one voice that one method is better than the other though the majority view seems to be in favour of lockdown.

Lockdown methods aim at lowering the reproduction number, ie. the actual number to whom each infected person could transmit the infection. Herd immunity attempts to allow people less likely to die lead their normal life thereby allowing the disease to spread causing immunity in a majority, while protecting those at high risk. Opponents say lockdown method doesn’t prevent but only delays the spread of infection. On the other hand herd immunity is said to be unethical and perhaps criminal allowing a viciously virulent virus free access to susceptible people.

England and Sweden had been suitable countries for comparative study and several researchers had studied the method adopted to control Covid in these two countries. Infection and death rates have been determined and analyzed using sophisticated statistical methods. England had first tried out herd immunity and later changed over to lockdown methods after advisers had asked Prime Minister Boris Johnson how many millions will have to die before herd immunity became effective and a mathematical model had shown that 5100000 would die if steps to lockdown are not taken. Sweden had chosen herd immunity from the time Covid started in that country up to the present. Some studies compare the situation in Sweden with that of other Scandinavian countries that had adopted lockdown methods.

According to most of the studies incidence of infection and death rates in England had come down after it started lockdown. Further it was found that these rates in England were lower compared to those in Sweden (Moaath K, et al, 2020, Thomas L, Aug. 2020). The daily incidence of infection dropped by 19 cases per 10 million after the lockdown in England compared to Sweden, and death rate by two deaths per 10 million. Also rates in Sweden were high compared to those in other Scandinavian countries such as Netherlands and Finland which had opted for lockdown methods.

Notwithstanding all these findings a statement known as the Great Barrington Declaration has been issued by three eminent scientists; epidemiologists from Harvard and Oxford and community medicine expert from Stanford and also several other cosigners. They are of the opinion that lockdown is a case of the cure being worse than the illness. Lockdown not only disrupts the economy but also the health of the people as normal health activities like vaccination of the young and cancer screening of the elderly are not possible. These could be irreparable effects that cannot be corrected after Covid.

However critics say herd immunity method could cause long term health consequences, which are known as Long-Covid, in the young as well as the elderly. Four types of syndromes are identified as Long-Covid cases, some have permanent damage to lungs and heart, others get post infection fatigue, some end up with continuous Covid symptoms and some have post ICU syndrome. These complications have prompted epidemiologists like G. Gonsales of the Yale University to say herd immunity method is nothing but “culling the herd of the sick and the disabled. It’s grotesque”. There are researchers who conclude that herd immunity has failed in Sweden. They have found that antibodies are not present in the mildly ill or the asymptomatic patients which is central to the concept of herd immunity.

Population of Sweden is about half that of Sri Lanka. Number of Covid cases in Sweden is more than 100,000 and deaths almost 6000. In contrast we have in Sri Lanka with double the population about 6000 cases and 13 deaths, what a contrast !. Is there any reason why we should change our strategy in tackling Covid. The first wave was controlled with an island-wide curfew and lockdown in the affected areas. Cases were cut down to a minimum and this allowed the limited health facilities to be used with optimum results, the death rate being among the lowest in the world. Our concern for stranded citizens in foreign lands where Covid raged made us make a special effort to bring them home and some of them came with Covid and have caused a second wave. Should we grumble, I am sure not. This time around the strategy has somewhat changed with lessons learnt. There is no island-wide curfew, let us hope the need would never arise, and instead there is strict lockdown in the affected areas and in the rest of the country life goes on as usual. Let us hope the death rate would remain at present level and the infection brought under control. If the people cooperate with the health authorities and the armed forces and the police we could succeed yet again.

-N.A. de S. Amaratunga-