Herd Immunity a 'Dangerous Fallacy,' Lancet Open Letter Says

October 14, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

The scientific outcry over a proposal to use herd immunity to blunt the COVID-19 pandemic continues to grow. Today, an open letter signed by more than 80 biomedical experts states that the "renewed interest in a so-called herd immunity approach" is a "dangerous fallacy unsupported by scientific evidence."

The new letter comes in response to the Great Barrington Declaration, which was posted on October 4. That declaration, written by a group led by three epidemiologists, called for allowing COVID-19 to spread among less vulnerable groups while selectively protecting the vulnerable as a way to deal with the pandemic, a strategy they called "focused protection."

Since its publication, the declaration has drawn numerous cosigners and critics, as reported by Medscape Medical News.  

The new letter is something of a counter manifesto. Called the "John Snow Memorandum" — presumably named for the London physician who started the science of epidemiology in 1854 by tracking the local spread of cholera — it was published online as an open letter in The Lancet.

Implementing the type of strategy promoted by the Great Barrington Declaration authors "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," the authors of the John Snow Memorandum write. 

"Empirical evidence from many countries shows that it is not feasible to restrict uncontrolled outbreaks to particular sections of society," they continue.

What is needed instead are "effective measures that suppress and control transmission" and that are widely implemented. "Continuing restrictions will probably be required in the short term to reduce transmission and fix ineffective pandemic response systems," and "suppress SARS-CoV-2 infections to lower levels."

The authors, including corresponding author Deepti Gurdasani, MBBS, MD, PhD, from Queen Mary University of London, United Kingdom, acknowledge that lockdowns have been disruptive for the economy and difficult for individuals. But they also note that these effects have been worse in countries that have not established pandemic control systems."

The John Snow Memorandum cites Japan, Vietnam, and New Zealand as models of "robust public health responses," demonstrating that the steps these countries took "can control transmission, allowing life to return to near normal."

At the time of publication, the signatories included clinicians and researchers from numerous countries and regions, including Europe, North America, Asia, and the Middle East.

For more news, follow Medscape on Facebook, Twitter, Instagram, and YouTube.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.