I know this is quite old, but the question struck me only recently during a discussion.

Applying the herd-immunity concept to humans is about 100 years old, so clearly it made sense to come into the political agenda shortly after COVID-19 hit the world. Despite sounding like a bad idea and also confirmed to actually be a bad idea by epidemiologists (and later on by the overrun ICUs), a few politicians promoted the idea of reaching herd immunity by simply exposing people to the virus. An example is Boris Johnson, who allegedly even tried to promote this idea on TV by intentional infection.

Did any high official (e.g. president, member of the government or parliament) promote "fighting" pandemics by reaching herd immunity like this for a disease other than COVID-19?

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    The title is a bit confusing for me. Commented May 31, 2021 at 21:09
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    Back in the day, children would be deliberately exposed to chicken pox to help achieve herd immunity - the vaccine hadn't been developed back then, and chicken pox is less severe it you catch it when you're young. I don't know if any politicians specifically. endorsed this, but it was accepted practice. (Of course it was an old disease - if it were a new disease that the adult population were susceptible to, things would have been different.)
    – Mazement
    Commented Jun 1, 2021 at 4:37
  • You could say this was really very similar to most vaccinations - most vaccines before Covid contain weakened or dead viruses, so you get immunity by getting a very weak case of the illness. If getting the illness at a very young age does the same, it's not so much difference.
    – gnasher729
    Commented Jun 2, 2021 at 10:02

3 Answers 3


Yes. The vast majority of vaccine programs have herd immunity as their goal, either explicitly or implicitly.

Importantly, herd immunity is not an approach, it is an attribute of a population.

A population can be said to have reached herd immunity when enough members of that population are fully inoculated against a given disease so as to prevent a sustainable infectious spread (in other words the average number of people infected by a sick person is less than 1, resulting in the eventual die off of the pathogen).

By definition, vaccines are a herd immunity strategy. It is actually impossible to achieve a 100% vaccination rate, as there will never be a vaccine that is safely tolerated by every human on the planet. Instead, the goal is to reduce the number of candidate hosts for the pathogen by vaccinating as many people as possible (the target number for herd immunity varies by pathogen).

In some diseases, contraction of the disease (e.g. chickenpox) is an effective means to attain immunity. If the disease is generally low-risk (e.g. chickenpox), then it becomes feasible for exposure to be used as a means of achieving inoculation. For much of my childhood this was the de facto means by which chickenpox (for which there was not a readily available vaccine at the time) was confronted as a public health issue: invariably someone at a school would contract it, it would spread through the student body despite everyone's best efforts to avoid this, but since chickenpox infections during youth are generally low risk, everyone from parents to school officials on up shrugged their shoulders and considered this to be standard operating procedure.

Of late, there has been a misunderstanding of this strategy by the lay public, leading to things like "measles parties." The problem there being that measles is not a low-risk disease, it is quite often fatal. Public officials saying "just get the disease and get it over with" is an artefact of that recent social development rather than the understanding of herd immunity.

  • It's not so simple. For example, the tetanus vaccine aims at preventing infections on an individual level as the disease doesn't spread between people anyway. In Europe, the flu vaccine is only recommended for high-risk groups so here again the aim is primarily to protect vaccinated people rather any population-wide effect.
    – Relaxed
    Commented Jun 1, 2021 at 18:00
  • @relaxed Fair enough, I'll adjust the language about vaccines away from the absolute. As to the vaccine against the flu, that's a supply/resource issue rather than anything to do with an ideal outcome. The flu is extremely difficult to vaccinate against, but the point of high-risk groups getting the vaccine is, in part, to protect their immediate high-risk peers as well. The scope of "population" is flexible to context. Commented Jun 1, 2021 at 18:07
  • @JonathanReez The second an infant is born, the vaccination rate drops below 100%. Even a perfectly efficacious vaccine will have age recommendations Commented Jun 1, 2021 at 18:16
  • @JonathanReez True, but in reality, the level of protection varies from individual to individual. So even if you have a true 100% vaccination rate, there are still individuals with some level of susceptibility
    – divibisan
    Commented Jun 1, 2021 at 19:18
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    @agc Howso? I can't make a change if you're vaguebooking at me. Commented Jun 2, 2021 at 13:08

This article says that

Kentucky Gov. Matt Bevin made headlines recently when he admitted to purposefully exposing his nine children to chickenpox rather than getting them the widely available chickenpox vaccine.

Another article says essentially the same thing.

Note: From what I can tell the governor didn’t explicitly tell people to do this, but if he did it, and then told the media he did it, it’s very similar to telling his supporters to do it.

Bias evaluations of the sources I used: First source Second source

  • Re "Fact check of the sources I used...": media bias evaluations are not fact checks. It's generally not necessary here to provide media bias evaluations -- readers here regularly check out sources, and if the source is biased some commentator should eventually point that out. (Alas, sometimes if the source is biased, similarly biased partisans will for that reason shamelessly upvote it!)
    – agc
    Commented Jun 2, 2021 at 1:46
  • @agc my bad, I confused fact checks and bias checks. Also, for your second point, I did that to pre-empt any commentators by pointing out a bias check. And I sure hope I haven’t gotten upvotes for partisan reasons, but seeing as how some of my questions have occasionally reached HNQ, I almost certainly have sadly. Commented Jun 2, 2021 at 2:04

There are claims that the British government wanted to propose to get Covid herd immunity by letting everyone get infected with Covid. I heard rumors that the UK government wanted to follow this strategy maybe March or April 2020. Recently, with Dominic Cummings answering questions in parliament, there have been strong claims that this was considered and claims that it was never considered.

We don't know what actually happened. Maybe someone in government asked quite reasonably "how can we achieve herd immunity", and some scientist answered equally reasonably "because we don't have a vaccine, the only way to achieve herd immunity is by letting everyone get infected". Which is true on one hand, and the worst possible outcome on the other hand. Herd immunity by vaccinating everyone is good. Herd immunity by infecting everyone is very bad.

It is quite possible that there were politicians who didn't understand the scientists advice and talked to the press. It is also possible that they understood the scientists advice, talked to the press, and it was reported differently.

But achieving herd immunity this way never became official policy in the UK. Because it is such an outrageously bad idea, even in the UK government a majority would have recognised it as such, and I believe some scientists would have switched from polite advice to very strong and impolite advice before they let this happen.

  • There were senior people in the UK gov advocating for it: Sir Patrick Vallance told the BBC “Our aim is to try to reduce the peak, broaden the peak, not suppress it completely; also, because the vast majority of people get a mild illness, to build up some kind of herd immunity so more people are immune to this disease and we reduce the transmission, at the same time we protect those who are most vulnerable to it.”
    – Dave
    Commented Jun 2, 2021 at 11:16
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    The question was about outbreaks other than covid-19. As this focuses only on the current pandemic, it is not an answer to the question. Commented Jun 2, 2021 at 11:31

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