Herd immunity

An article from Johns Hopkins University describes herd immunity as:

When most of a population is immune to an infectious disease, this provides indirect protection – or population immunity (also called herd immunity or herd protection) – to those who are not immune to the disease.

The article gives examples of measles, mumps, polio, and chickenpox as diseases for which herd immunity exists in the U.S. Outbreaks of these diseases can still occur in pockets of unvaccinated people, but due to herd immunity, they fade away and don’t spiral out of control. If we had herd immunity to COVID, there would still be sporadic, limited outbreaks here and there, but no sustained transmission of the virus.

We do not have herd immunity to COVID.

It’s Mad That ‘Herd Immunity’ Was Ever a Taboo Phrase

With this definition of herd immunity in mind, let’s flashback to May 27th, 2021. On that day, two of the authors of the Great Barrington Declaration (GBD), Drs. Jay Bhattacharya and Martin Kulldorff, published an overly optimistic article titled It’s Mad That ‘Herd Immunity’ Was Ever a Taboo Phrase. They said:

Herd immunity is fundamental in epidemiological science. COVID spreads in populations when infectious individuals come in contact with individuals who are not already immune. Herd immunity reflects the obvious concept that an uninfected individual is less likely to catch the disease when a larger part of the population is immune. While COVID cannot be eradicated, herd immunity assures that in the long run, it will stay at low levels with few hospitalisations and deaths.

Just like gravity, herd immunity is a scientific fact. To the shock of many infectious disease epidemiologists, politicians, some media, and scientists turned it into a dirty word. Some talked about a ‘herd immunity strategy,’ but every strategy leads to herd immunity, so that is as nonsensical as pilots using a ‘gravity strategy’ to land a plane. The plane will reach the ground no matter what; the key is to land safely….

This denial of a basic scientific concept by so many prominent authorities is stunning. Rather than engage in a good-faith debate on how to protect the elderly better while minimising collateral public health damage from lockdowns, it was easier to demagogue the issue, turning a basic scientific concept – herd immunity – into a propaganda weapon to demonise lockdown opponents within the scientific community…

We now have considerable COVID immunity in the US and the UK, primarily due to natural infections with some help from vaccines. We know this since COVID deaths peaked three months earlier in 2021 than in 2020, while most people were still unvaccinated. As we enter summer with a lower herd immunity threshold, there are no public health reasons to keep the current lockdowns in place. Even the staunchest lockdown supporters should leave the summer months alone. If they understood herd immunity, they would.

As with everything from these doctors, this aged poorly. COVID’s death toll us the USA was 589,000 at the time, and immune-evading variants have since killed nearly 600,000 more Americans and sickened many millions more. Moreover, the last remnants of “lockdown” were going away forever when the piece was published.

However, the title – It’s Mad That ‘Herd Immunity’ Was Ever a Taboo Phrase – is worth discussing. In one sense, it was as wrong as the content of the article. However, in another sense it was just ahead of its time.

‘Herd immunity’ wasn’t a taboo phrase

The title was wrong in that herd immunity wasn’t a taboo phrase in 2020 and 2021. In fact, many doctors, most of whom lacked real-world responsibility for treating COVID patients, discussed herd immunity all the time. As early as April 2020 an article appeared titled, Swedish Official Anders Tegnell Says ‘Herd Immunity’ in Sweden Might be a Few Weeks Away. In July 2020, an interview with the third author of the GBD was published titled We May Already Have Herd Immunity – an Interview With Professor Sunetra Gupta. In February 2021, Dr. Marty Makary wrote an editorial titled We’ll Have Herd Immunity by April and the next month he wrote another titled Herd Immunity Is Near, Despite Fauci’s Denial. In May that year he said, “Most of the country is at herd immunity.” In February 2021, an article was published titled Pandemic Exit Interviews: Stop Panicking About the COVID-19 Variants, Says UCSF’s Monica Gandhi. Dr. Gandhi also recorded a podcast with Dr. Zubin Damania that month tilted The End of the Pandemic. In March 2021, Dr. Lucy McBride wrote an article titled I’ve Been Yearning for an End to the Pandemic. Now That it’s Here, I’m a Little Afraid. An article from May 2021 was titled California ‘Weeks Away’ From Reaching Herd Immunity, UCSF Doctors Say. There are many more examples. Though he would later say herd immunity was “unattainable” for COVID, even Dr. Anthony Fauci, the GBD’s scapegoat, was the subject of an article from December 2020 titled Fauci Predicts U.S. Could See Signs Of Herd Immunity By Late March Or Early April.

“The term is herd immunity”

The GBD itself talked about herd immunity extensively. It very reasonably defined herd immunity by saying:

Herd immunity occurs when enough people have immunity so that most infected people cannot find new uninfected people to infect, leading to the end of the epidemic/pandemic.

It also said:

When herd immunity is reached, they (vulnerable people) can live normally again with minimal risks. How long that takes depends on the strategy used. If age-wide lockdown measures are used to try and suppress the disease, it could take a year or two or three, making it very difficult for older people to protect themselves for that long. If focused protection is used, it will likely only take 3 to 6 months.

The Twitter feed of the GBD had multiple tweets about herd immunity – in 2020 and 2021. In December 2020, they said:

For COVID-19, all strategies lead to herd immunity, making it nonsensical to denote one specific approach as a herd immunity strategy just as it does not make sense for airplane pilots to talk about a “gravity strategy” for safely landing a plane. The Declaration advocates a strategy that minimizes mortality until herd immunity is reached. That is done by minimizing the number of older high-risk people in the group that get infected while maximizing them among those that are still uninfected when herd immunity arrives.

They had good news to share. They said:

Despite an estimated 750 million worldwide to date after 10 months living with the virus, we have seen only a handful of reinfections. If the virus is like other corona viruses in its immune response, recovery from infection will provide lasting protection against [sic].

They again said herd immunity could arrive in less than 6 months. In December 2020, they had the following Twitter exchange:

Question: So at six months you would anticipate herd immunity in the young and fit and it would be safe for the vulnerable to reintegrate to society?

Answer: Yes, between 3 – 6 months and then natural immunity should be at an acceptable level.

‘Herd Immunity’ is now a taboo phrase

The title was ahead of its time in that after 2021, mentions of herd immunity essentially stopped. The few doctors who mentioned herd immunity after this, did so only to absurdly redefine the term to make it seem as they had been right all along. Blatantly contradicting what he wrote in the GBD, Dr. Bhattacharya, said in December 2022:

Herd immunity for coronaviruses means a widescale decoupling of cases from deaths caused by the virus due to immunity.

However, most doctors who spoke ceaselessly about herd immunity in 2020 and 2021, refuse to do so today. In fact, they act as if they had never mentioned herd immunity at all. There has been scant acknowledgement that their preposterous predictions of the pandemic’s end failed to arrive. They’ve made no effort to grapple with the real-world consequences of telling people herd immunity was around the corner, when in fact the worst was yet to come. Instead of reflecting on their previous claims of herd immunity, these doctors now encourage repeat mass infection, saying:

Repeat infections are inevitable. More the longer you live. Nothing can be done about it.

And thus it becomes clear, doctors who previously mocked and berated those who supposedly treated herd immunity as a taboo phrase, now treat herd immunity, as they defined it in 2021, as a taboo phrase. As cases and hospitalizations rise once again, I wonder why that is.


  • Dr. Jonathan Howard is a neurologist and psychiatrist who has been interested in vaccines since long before COVID-19. He is the author of "We Want Them Infected: How the failed quest for herd immunity led doctors to embrace the anti-vaccine movement and blinded Americans to the threat of COVID."

Posted by Jonathan Howard

Dr. Jonathan Howard is a neurologist and psychiatrist who has been interested in vaccines since long before COVID-19. He is the author of "We Want Them Infected: How the failed quest for herd immunity led doctors to embrace the anti-vaccine movement and blinded Americans to the threat of COVID."