Experts: Herd immunity is 'dangerous' and 'flawed' approach

A crowd of people wearing masks at a subway station in Bulgaria.
(Image credit: Shutterstock)

The idea of using herd immunity to manage the COVID-19 pandemic — by allowing low-risk people to acquire the infection naturally as they resume their normal lives — is a "dangerous" and "flawed" approach, according to a new letter signed by 80 international researchers.

The letter, published Wednesday (Oct. 14) in the journal The Lancet, appears to be a response to the Great Barrington declaration, a proposal published earlier this month by three researchers that calls for an end to COVID-19 restrictions in favor of a herd-immunity strategy. Such a strategy, the declaration says, would involve allowing young and healthy people to return to their normal lives and build up immunity to the virus, while protecting vulnerable populations.

The Great Barrington declaration has allegedly been signed by tens of thousands of experts and medical practitioners, as well as members of the general public; however, the document garnered more controversy last week when many signatures were found to be fake, according to The Guardian.

The new letter, called the John Snow Memorandum, after the pioneer epidemiologist John Snow who first tied a London cholera outbreak to a contaminated water pump, calls this herd-immunity concept "a dangerous fallacy unsupported by scientific evidence." Evidence shows it is not possible to restrict uncontrolled outbreaks of COVID-19 to particular sectors of society, according to the authors, who include experts in public health, epidemiology, virology, infectious diseases and other scientific fields. "Uncontrolled transmission in younger people risks significant morbidity and mortality across the whole population," they wrote.

Related: 14 coronavirus myths busted by science

What's more, understanding who is vulnerable to COVID-19 is complex, and even young and seemingly healthy people have developed long-lasting symptoms after infection with COVID-19, known as "long COVID," the authors said.

Additionally, there's no solid evidence that people develop lasting immunity after natural infection with COVID-19. So allowing more people to catch the disease "would not end the COVID-19 pandemic but result in recurrent epidemics" and "place an unacceptable burden on the economy and health care workers."

As the United States and Europe face a second wave of COVID-19 cases, it "is critical to act decisively and urgently," the memorandum argues.

In the short term, restrictions will likely be needed to reduce transmission and give countries time to fix "ineffective pandemic response systems" to prevent future lockdowns, according to the letter.

"The purpose of these restrictions is to effectively suppress SARS-CoV-2 [the virus that causes COVID-19] infections to low levels that allow rapid detection of localized outbreaks and [a] rapid response … so life can return to near-normal without the need for generalized restrictions."

The authors noted that countries such as Japan, Vietnam and New Zealand have shown that it is possible to control COVID-19 transmission with the right public health tactics. In those countries, life has returned to near-normal.

"The evidence is very clear: Controlling community spread of COVID-19 is the best way to protect our societies and economies until safe and effective vaccines and therapeutics arrive within the coming months," the authors concluded. 

The memorandum has been posted online, with 80 signatures at the time of publication. Other experts in appropriate fields are invited to sign the document. And signatures will be checked before being added to the memorandum, according to the website.

Originally published on Live Science. 

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.

  • FB36
    I had recently read that Sweden did not do any lockdowns to cripple their economy & their new case numbers extremely low now & keep getting lower!

    Realize that, if everybody will get COVID-19, sooner or later, regardless of any prevention measures (true?), then best strategy would be, to keep open economy as much as possible (to minimize economic damage) but while always/only making sure hospital capacity never exceeded!

    (Strict economic lockdown, on the other hand, would never really prevent anybody/everybody from contacting the disease & cause massive economic damage!)
  • Chem721
    FB36 said:
    Realize that, if everybody will get COVID-19, sooner or later, regardless of any prevention measures (true?)

    This is not true. If a vaccine is created, used widely and is effective for a significant period, than a large number of people will not need to die, or suffer long lasting morbidity.
  • Chem721
    FB36 said:
    while always/only making sure hospital capacity never exceeded!

    This would be impossible to manage as the number of people needing critical care would still sky-rocket. Mixed-age families alone would be a major source of hospital admissions.

    Right now, some hospitals in the mid-West are at or near capacity, and that is with significant mitigation in many areas. Letting this virus run wild would overwhelm the medical system of the country. We either go with Darwinian concepts and herd immunity, or go with the experts' recommendations. Most will want to go with the experts. Darwin, who was a very smart guy, would almost certainly agree with the experts.

    The below is a cut-and-paste from a previous post on this exact topic from another thread :


    It would appear that we may be going with herd immunity unless something happens in the next few months to change the strategy.

    Forbes (1) presents this breaking news in a remarkably fact and science based article. It is not for the faint of heart. Some have referred to this proposal as the "Let People Die" approach.

    The Forbes article provides 8 good reasons NOT to allow herd immunity :

    1. Many deaths will occur.
    2. Suffering and long term health problems will occur.
    3. This could overwhelm a broken health care system.
    4. It’s not clear how long immunity may last.
    5. How do you define vulnerable people?
    6. How do you identify who is vulnerable?
    7. How would you actually protect the vulnerable?
    8. This could distract and distract from other possible strategies.

    ref. 1 :

    www.forbes.comWhite House Considering ‘The Great Barrington Declaration’ Herd Immunity Strategy For Covid-19 Coronavirus
    The Great Barrington Declaration is a petition that promotes "focused protection" a variation of a herd immunity strategy. Here are 8 problems with such an approach.
    The "Great Barrington Declaration" is defined in quotes from the Wiki link below, with critical notions about its practicality.(2). It is largely rejected by health experts around the world, which is not surprising if one is an expert of such matters.

    From (2):


    "The declaration advocates that individuals at high risk of death from infection should continue staying at home, and that people at low risk resume their normal lives, by working away from home and attending mass gatherings. They hope that as a result most of these lower-risk people will contract the infection but not die, and that the resulting immune response will prevent the SARS-CoV-2 virus from spreading to higher-risk people. The declaration makes no mention of social distancing, masks, contact tracing, nor of COVID-19 testing."


    Critics of the declaration's recommendations, including academics and the World Health Organization, have stated the proposed strategy is dangerous and unworkable and that it would be impossible to shield those who are medically vulnerable, and that the herd immunity component of the strategy is undermined by the limited duration of post-infection immunity." (emphasis mine)

    It goes on to note :

    It was sponsored by the American Institute for Economic Research, a libertarian think tank associated with climate change denial and the Koch Foundation."

    end quotes

    Reading through Forbes' 8 reasons NOT to accept herd immunity would have most people wondering about the wisdom of such an approach. It also brings into question the "wisdom" and true reasons behind its supporters.

    It is instructive to realize that over 1 million people world-wide have died from this virus as of mid-October, and that is after considerable mitigation efforts in most places. It is a certainty that millions more will die with the "Herd Immunity" approach, and many millions more with long-lasting disabilities.

    For the full Wiki article:

    Ref. 2 :
  • SHaines
    FB36 said:
    I had recently read that Sweden did not do any lockdowns to cripple their economy & their new case numbers extremely low now & keep getting lower!

    If you have a source for info, please link it so folks here can check it out as well.

    With that in mind, not every nation will benefit in the same way from every path forward. What works in one place may not work as well in another. With how high the US population is, how much global travel passes through here, the different policies enacted by different states within the country, it's just not possible to try every option, so we need to find the options that are likely to have the best outcome and test it out.