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The Herd Mentality of Herd Immunity

Dr. Scott Atlas is a neuroradiologist with no background in infectious diseases, who has become a medical adviser to the White House coronavirus task force. He has asserted that the pandemic is nearly over, that social distancing and masks don't work, and that vulnerable people should be sequestered in nursing homes while the coronavirus is allowed to spread naturally through the rest of the population. This strategy has been called herd immunity.

The White House Coronavirus Task Force has apparently abandoned attempts to contain COVID19 and instead adopted Atlas’ strategy of herd immunity. Below is a timeline of the White House’s actions and the responses of infectious disease experts.

On September 15 during an ABC town hall in Pennsylvania, President Trump defended his assertion that COVID19 would disappear with or without a vaccine. He said, “With time it goes away. “You'll develop, you'll develop herd — like a herd mentality. It's going to be, it’s going to be herd-developed, and that's going to happen. That will all happen. But with a vaccine, I think it will go away very quickly.”

On October 5, The Hill reported that epidemiologists Martin Kulldorff from Harvard; Sunetra Gupta from Oxford; and Jay Bhattacharya from Stanford, met with Health and Human Services Secretary Alex Azar and Dr. Scott Atlas at the White House to promote allowing SARS-CoV-2 to spread uncontrolled among healthy young people to achieve herd immunity while avoiding lockdowns and other mitigation measures. They presented a petition titled “The Barrington Declaration” which had 9000 signatures from all over the world. Two of the signatories had proposed that societies would achieve herd immunity when 10 to 20 percent of their populations had been infected. They called their strategy, “Focused Protection.”

On October 13, WHO Director-General Tedros Adhanom Ghebreyesus said that allowing the novel coronavirus to spread in an attempt to reach herd immunity was “simply unethical.” He also said, “Never in the history of public health has herd immunity been used as a strategy for responding to an outbreak, let alone a pandemic. It is scientifically and ethically problematic.”

On October 14, The Infectious Diseases Society of America denounced the Great Barrington declaration. IDSA stated, “Promoting the concept of ‘herd immunity’ as framed in a recently circulated document as an answer to the COVID-19 pandemic is inappropriate, irresponsible and ill-informed. ‘Community immunity,’ or ‘herd immunity,’ a goal of vaccination campaigns, should never come at the cost of planned exposure to infection of millions of additional people as well as the severe illness and preventable deaths of hundreds of thousands of people.”

On October 14, a scientific consensus on COVID-19, entitled the Snow memorandum, was published in the Lancet, which concluded that any pandemic strategy relying on herd immunity was flawed. Uncontrolled transmission in younger people risks significant morbidity and mortality across the whole population.

On October 17, Dr. Tom Frieden, former CDC director and CEO of Resolve to Save Lives, tweeted, “Less than 15 percent of Americans have been infected by Covid. If immunity is strong & long-lasting (it may well be neither), and if herd immunity kicks in at 60 percent infection (it might be higher), then AT LEAST another 500,000 people will die before we get to herd immunity.”

On October 18 during an interview on NBC’s Meet the Press, Michael Osterholm said that a “herd immunity” theory reportedly invoked by Dr. Scott Atlas “is the most amazing combination of pixie dust and pseudoscience I’ve ever seen.”

Proponents of herd immunity suggest that it would lead to the development of infection-acquired population immunity in the low-risk population, which would eventually protect the vulnerable. However, most experts feel this is a dangerous strategy unsupported by scientific evidence. Empirical evidence from many countries has demonstrated that it is not feasible to restrict uncontrolled outbreaks to segments of society. If coronavirus is allowed to freely spread among younger people, it will eventually spread to older adults and medically vulnerable individuals, who comprise a sizeable proportion of the population. In 2018, there were 52 million adults 65 years and older and 60 percent of adults were estimated to have a preexisting medical condition that increases their risk of death from COVID19.

Most epidemiologists agree that 60 to 70 percent of the population needs to become immune to SARS-CoV-2 to decrease sustained transmission. Seroprevalence studies indicate that only 10 to 15 percent of the population has been infected. Reaching the herd immunity threshold safely would be nearly impossible without an effective vaccine.

If the vulnerable cannot be protected, hospitalizations and deaths will increase. In addition to the human cost, a strategy of herd immunity would negatively impact the economy and overwhelm health-care systems. The socioeconomic inequities already exposed by this pandemic would widen even further.

Lastly, there is no definitive evidence that natural infection with SARS-CoV-2 produces long term protective immunity. Widespread viral transmission together with waning immunity would keep vulnerable populations at risk for the indefinite future.Herd immunity might not end the COVID19 pandemic but instead result in recurrent epidemics. Vulnerable patients could even become reinfected.

Instead of promoting herd immunity, the government needs to actively support and widely implement effective measures that have been proven to suppress viral transmission. Mitigation can be achieved by physical distancing, face masks, hand and respiratory hygiene and avoiding crowds and poorly ventilated rooms. Widespread adoption of these interventions can suppress SARS-CoV-2 to low enough levels that localized outbreaks can be contained and generalized lockdowns can be avoided. Of course, government must provide comprehensive test, trace, isolate and support systems.


Omer SB et al. Herd Immunity and Implications for SARS-CoV-2 Control. JAMA published online October 19, 2020.

Alwan NA et al. Scientific consensus on the COVID-19 pandemic: we need to act now. Lancet published online October 14, 2020.

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