One of the biggest controversies around the current COVID-19 pandemic involves the question of immunity. The official WHO position is as following:

"Some governments have suggested that the detection of antibodies to the SARS-CoV-2, the virus that causes COVID-19, could serve as the basis for an 'immunity passport' or 'risk-free certificate' that would enable individuals to travel or to return to work assuming that they are protected against re-infection," the WHO wrote. "There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection."

Were there similar concerns in society during the 1918 Spanish flu pandemic?

  • Notes: CV19 is akin to the common cold but not to flu, some many comparisons are inappropriate. || Flu 'mutates' so that given enough time (usually tears) a flu which has been experienced may translate to one which is different enough that earlier antibodies are less effective or ineffective. The same applies to Corona viruses 'but different'. || We've not had a vaccine for the common copld. That may be about to change. Maybe Apr 29, 2020 at 4:25
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    @RussellMcMahon yeah, but somehow people are still spreading the idea that no one can be immune to COVID-19... Apr 29, 2020 at 4:42
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    It seems tye reality is "somewhere in the middle" . There are reports of SOME reinfections and some re-ellivenings. As a non medical layman but avid consumer of information I'd expect significant immunity but not universal. Apr 29, 2020 at 6:00
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    I wouldn't say that there is a controversy. It's more like people don't understand that answering the questions that are currently important normally takes years of clinical studies, and we have only been studying this virus for 5 months. We simply do not know most of the answers. It is unfortunate that the information that we need to make decisions now will only be available in the future, but that is a problem that people need to understand. That's not controversy that's just a fact of decision making. Hindsight, as always, is 20/20. Apr 29, 2020 at 8:40
  • @JörgWMittag 4 years later it’s obvious this was nonsense and questioning the concept of immunity after recovery was done purely for political reasons. Jan 26 at 15:47

1 Answer 1


The statement by the WHO reflects uncertainty, but also a comparatively advanced knowledge of what is actually happening. We know that there is a virus that causes the disease and we know that people develop antibodies in response to that virus. We know that immunity is a very likely possibility, we just aren't sure if it's guaranteed.

The situation in 1918 was very different. The overall uncertainties were much greater. The discovery of antibodies was much more recent and our understanding of them more rudimentary. Influenza viruses were not discovered until the 1930s. The efforts to develop an influenza vaccine in 1918 still assumed the disease was caused by bacteria. (EDIT: However, as @JonathanReez shows in the comments, the general concept of immunity through exposure was a possibility known since ancient times.)

If one looks at research conducted shortly after the fact, scientists were only beginning to suspect that people who got the 1918 flu in one wave probably became immune to it in the subsequent waves. Statements about immunity are notably tenuous. For example:

Concerning the important question of the immunity conferred by an attack of influenza, the evidence is not conclusive [...] Parsons, from his study of the last epidemic, inclines to the view that an attack of influenza in the earlier years of the epidemic conferred a considerable but not absolute immunity in the later outbreaks.

(EDIT: Military leaders had similar suspicions based on their observations and experience. Here is an article that documents this in the US context.)

It would be interesting to look at more general public discussions from 1918 about if and when the high mortality was going to end. Based on past epidemics, people may have assumed it would end soon. But I don't expect you will find statements quite like the one quoted in the question because it was not widely assumed in the first place that antibodies would protect from re-infection.

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    But people did know about the concept of inoculation based on their experience with chickenpox and smallpox? Thus they understood that people who had a disease once won't have it again. Or am I mistaken? Apr 27, 2020 at 20:41
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    I think that's right, yes. But there were and are so many other diseases that don't work like that.
    – Brian Z
    Apr 27, 2020 at 20:47
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    @JonathanReez I added a quote to my answer to emphasize that scientists were still figuring that out as of 1919. Indirectly, I think this suggests that average people had no reason to be confident that they could not get sick a second time.
    – Brian Z
    Apr 28, 2020 at 0:09
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    It was noticed at the time (at least in Germany) that those who had recovered from the first wave, often soldiers, had less problems when they were reinfected during the second wave. Apr 28, 2020 at 4:34
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    @JonathanReez: People were aware of the general principle much longer than that: e.g., Thucydides writes that people struck by the Athenian plague could not get it a second time. Yet it was with those who had recovered from the disease that the sick and the dying found most compassion. These knew what it was from experience, and had now no fear for themselves; for the same man was never attacked twice—never at least fatally. The only question could've been whether or not they thought the Spanish flu was this kind of disease, that could or could not strike twice, which is a natural one.
    – Shamshiel
    Apr 28, 2020 at 11:47

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