International warning against 'dangerous fallacy' of herd immunity

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A second wave of infections has led to renewed interest in ending the COVID pandemic through a herd immunity approach, write 80 prominent scientists in a warning letter in The Lancet. The idea “a dangerous fallacy unsupported by scientific evidence”.

The signatories have expertise spanning public health, epidemiology, medicine, paediatrics, sociology, virology, infectious disease, health systems, psychology, psychiatry, health policy, and mathematical modelling, reports The Guardian. They include a number of scientists who sit on the breakaway Independent Sage group in the UK, such as former chief scientist Sir David King, former World Health Organisation (WHO) director Anthony Costello, virologist Professor Deenan Pillay, behavioural scientist Professor Susan Michie and professor of European public health Martin McKee.

Other signatories to the letter from the UK include epidemiologist Professor David Hunter, cancer researcher Professor Charles Swanton of the Crick Institute and global health professor Devi Sridhar. Those from the US include global health professor Gavin Yamey of Duke University, Professor Rochelle P Walensky from Harvard Medical School and Dr Ali Nouri of the Federation of American Scientists. Researchers from Italy, Israel, Malaysia, Spain, Ireland, Germany, France, Australia, the Netherlands, Switzerland and Canada have also signed.

The signatories write:

“While lockdowns have been disruptive, substantially affecting mental and physical health, and harming the economy, these effects have often been worse in countries that were not able to use the time during and after lockdown to establish effective pandemic control systems. In the absence of adequate provisions to manage the pandemic and its societal impacts, these countries have faced continuing restrictions.

“This has understandably led to widespread demoralisation and diminishing trust. The arrival of a second wave and the realisation of the challenges ahead has led to renewed interest in a so-called herd immunity approach, which suggests allowing a large uncontrolled outbreak in the low-risk population while protecting the vulnerable. Proponents suggest this would lead to the development of infection-acquired population immunity in the low-risk population, which will eventually protect the vulnerable.

“This is a dangerous fallacy unsupported by scientific evidence. Any pandemic management strategy relying upon immunity from natural infections for COVID-19 is flawed. Uncontrolled transmission in younger people risks significant morbidity and mortality across the whole population. In addition to the human cost, this would impact the workforce as a whole and overwhelm the ability of health-care systems to provide acute and routine care.

“Furthermore, there is no evidence for lasting protective immunity to SARS-CoV-2 following natural infection, and the endemic transmission that would be the consequence of waning immunity would present a risk to vulnerable populations for the indefinite future.

“Such a strategy would not end the COVID-19 pandemic but result in recurrent epidemics, as was the case with numerous infectious diseases before the advent of vaccination. It would also place an unacceptable burden on the economy and health-care workers, many of whom have died from COVID-19 or experienced trauma as a result of having to practise disaster medicine.

“Additionally, we still do not understand who might suffer from long COVID. Defining who is vulnerable is complex, but even if we consider those at risk of severe illness, the proportion of vulnerable people constitute as much as 30% of the population in some regions.

“Prolonged isolation of large swathes of the population is practically impossible and highly unethical. Empirical evidence from many countries shows that it is not feasible to restrict uncontrolled outbreaks to particular sections of society. Such an approach also risks further exacerbating the socioeconomic inequities and structural discriminations already laid bare by the pandemic. Special efforts to protect the most vulnerable are essential but must go hand-in-hand with multi-pronged population-level strategies.”


Full report in The Guardian


Full letter in The Lancet



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