Life can go back to normal if we make it our common goal to achieve herd immunity

When asked how it all began for me, the image that returns is of  the 90 year-old street vendor walking back home to her village because lockdown has now forbidden her to sell the few toys on the pavements of Delhi that might occasionally have provided her with a bit of food to eat.

The costs of the Covid-19 pandemic were divided, right from the start, between the deaths caused by the disease itself and the deaths that have occurred – in many regions, from their inception – by the restrictions imposed to stop the spread of the virus.

It has always been our duty, as international citizens, no matter what our political affiliation, to weigh these up against each other to arrive at the most humanitarian solution to this problem.

Naturally, an understanding of the dynamics of the spread of SARS-CoV2 (the virus responsible for Covid-19) is of importance in making these difficult decisions. Mathematical models can be very useful in this regard, and these are all built on the premise that recovery from infection leads to immunity (not necessarily lifelong).  

The build-up of “herd immunity” simply describes the ecological process by which immunity accumulates in a community to the detriment of the pathogen; it does not contain any implication or acceptance of culling those who are vulnerable to disease. To steer a population towards high levels of herd immunity is a sustainable public health goal upon which we have relied to manage a very large catalogue of infectious diseases.

While we remain uncertain about levels of herd immunity that have been attained to SARS-CoV2, we do now have a relatively clear picture of who is vulnerable to severe disease and death upon infection.

The Great Barrington Declaration proposes that we exploit this feature of Covid-19 to formulate a strategy of Focused Protection, whereby those who are at high risk may be shielded to varying degrees over the period (a maximum of six months) it takes to acquire sufficient herd immunity while the majority of the population conduct normal lives – thereby protecting the whole community from the devastating effects of lockdown.

Is this practicable?

To answer this, the problem needs at first to be broken down into several parts. A relatively straightforward aspect is the protection of care homes and infection control in hospitals; fortunately it is also the largest component of this problem.

We then come to at-risk individuals who either live in separate residences or for whom the family home can be structured to isolate them, as best possible, over the period of danger. This, it would seem to me, is not much different to the conditions imposed by lockdown – except, unlike the prospect of repeated lockdowns, there is always an end in sight.

Separating vulnerable members within a family from those who are not vulnerable (such as within multi-generational households) is naturally a more complex problem but it is important to remember that it is only for a finite period.

Resources need to be channelled into providing acceptable solutions, such as the temporary housing of those at risk in settings where they can safely interact within closed bubbles.

Or it may be that the family chooses to home school their children over that period; a strong investment in catch-up schooling and personal tutoring opportunities following the period of isolation may go some way towards addressing the education and aspiration gaps that would have yawned wider as a result.

Such inequalities will only be further exacerbated by endless cycles of lockdowns and other restrictions aimed at keeping “case” numbers low. Once sufficient levels of immunity have built up in the population such that the overall risk remains low (and this may already have happened in many areas), life can go back to normal for everybody.

It should be our common goal to achieve such a state – which will be augmented by the availability of vaccines but cannot rely solely on that route – without causing irreparable damage to those who are vulnerable to other diseases, to the disruption of education and training, to job losses and food insecurity.

Indeed, we should use this opportunity to restructure our social systems to address many of their inadequacies – gaps in healthcare and education – that this pandemic has dragged into an even harsher light than before.

Professor Sunetra Gupta , Professor of Theoretical Epidemiology, Department of Zoology, University of Oxford

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