It seems the White House recently embraced a lethal idea – the utopian view of herd immunity from infection, and that too for a virus that has already taken more than a million lives. If you are new to the history of medicine, just be reminded that “herd immunity from natural infection” has never happened in the history of mankind.
The entire conspiracy appears to stem from one dubious declaration. The thing has already achieved notoriety among sensible scientific communities by now and is named “ The Great Barrington Declaration”. Its greatness is nothing but the sheer arrogance of leading businessmen to state that the business of making money is what matters and not the business of living healthy.
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What worries me a lot is the fact that this unscientific document has already gathered more than 9,000 signatures worldwide and many of the signatories are prominent, well-educated personalities including some top scientists. What is the value of education if you can’t see the suffering by millions of people on a global scale?
Is human life a tradable commodify with a price tag?
The document is purely on business and grew out of a meeting hosted by the American Institute of Economic Research, a libertarian leaning research organisation. President Donald Trump appears to be fascinated with this idea, so is his science advisor Dr Scott Atlas who is busy using every minute to override the good old virus doc Dr Anthony Fauci.
Dr Jay Bhattacharya, an epidemiologist and infectious disease expert at Stanford University, (academic home of Dr Atlas) is the lead author of this new idea of letting all infected except the elderly (don’t ask me how we can do this). They call it focused protection. Dear America, we already saw focused protection in all your nursing homes by now. Is there a single such place remaining in the whole of America that can be classified as safe?
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Dr Bhattacharya and his team have a brilliant theory about herd immunity. Nobel prize is just round the corner. Two reputed personalities who are part of the team that drafted the document — Sunetra Gupta and Gabriela Gomes — proposed that populations may achieve herd immunity when 10-20% get infected with the virus, a position most epidemiologists including yours truly disagree with. Dr Christopher JL Murray, director of the University of Washington’s Institute for Health Metrics and Evaluation is certain that this 10-20% herd immunity threshold (HIT) is nothing but utter nonsense.
Understand your percentages better
The underlying principle of this herd immunity phenomenon is that when populations get enriched with people who are immune to an infectious disease, these immune guys will not transmit the disease to the non-immune, susceptible population. In fact, immune people become efficient barriers to disease transmission and thereby protect the non immune population from the deadly bug. A steady increase in proportion of immune people will slow the spread of the disease, causing the decline to zero (eradication).
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The greater the share of immune individuals in a community, the smaller the probability that susceptible individuals will come into contact with an infectious individual, helping to shield non-immune individuals from infection. The point most people forget when we discuss herd immunity is that there are two major substrates that contribute to reaching this “golden state”. Individuals can only become immune by recovering from an earlier infection or through vaccination. Before the vaccine era, we never eradicated any disease because only one substrate – natural infection was present. But once vaccines appeared on the scene, things changed rapidly. We are close to eradicating many illnesses like measles, mumps and polio.
How will we decide how many people will have to be immune to protect the remaining? This can be calculated from R0, the reproduction number we all know by now. (If you don’t, it is the number of people infected if an infected person mingles freely in the community with those never exposed to the disease). For Covid-19, the global estimates are now somewhere between 2 and 3.5. There is a general consensus that roughly 60-70% of the population needs to be immune to achieve herd immunity for coronavirus. We epidemiologists call this magic proportion (0.60 or 0.70 in this example) herd immunity threshold for Covid-19.
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So now you can see that the 10-20% proposed by the proponents of the great Barrington Declaration is far away from the values believed and shared by lead epidemiologists and scientists in this area. Already three recent epidemiological models based on the latest available data have rejected these newly proposed low values.
Looks like America hasn’t learned its lessons yet. The country had lost 220,000 lives so far and is still losing at a rate of 1000 per day. The country is in its third wave and there are no signs of herd immunity happening anywhere in the country. But business houses are certain that herd immunity is round the corner and it’s time to open up all businesses including schools. Just look at all those places where schools were opened recently. The answer is there for everyone to see.
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When you have time, please look at the number of young/middle aged people who perished in your country after getting Covid-19 infection. And if possible, read about the millions including healthcare workers battling the long-term consequences of Covid. You will see the truth on your own.
As the old saying goes the show must go on and the purse must swell. Yes, but just remember that the graveyards too will follow the same.
(Dr Manu Raj is a pediatrician, clinical researcher and research methodologist based in Kochi.)