From Our Mailbag: Did the Influenza Virus Cause the 1918-1919 Influenza Pandemic?

We get very interesting emails sometimes. The overwhelming majority of them are from people thanking us for our work on the History of Vaccines project, or with constructive criticism on how to make the project better. Once in a while, we get an email from a person questioning the historicity of events we cover, or they question the science and evidence of vaccination. Some of the email senders are somewhat justified in their skepticism of vaccine science. After all, many of the concepts that go into the science and history of vaccines can be very complicated.

For example, a recent email questioned the cause of the 1918-1919 influenza pandemic, stating that it was not the influenza virus that caused it, that it was caused by a bacterium, and that the bacterial infections appeared from a vaccine against meningitis given to American troops. They further stated that viruses were not discovered at the time of the pandemic. First, the facts:

In their email, the reader/skeptic states some truisms that seem to prove their case:

  • “The CDC has even posted an article that people died from bacterial flu and pneumonia in 1918 and not a virus as your site says after a large worldwide study was done in the 1980s proving it.”
    FACT CHECK: Yes, as stated in the facts above, many people had a secondary bacterial infection that resulted from their weakened state from the influenza infection. However, for this to happen, the influenza virus was necessary. Absent the virus, those secondary infections likely do not happen. There is even some thought that a previous influenza (H3N8) infection led to a debilitated H1N1 response from the immune system. (Source:
  • “The CDC tries to still blame it on a virus, but there was no methods back then for detecting any virus and the Study shows people only dying from bacterias (sic). Authors are just assuming a virus was involved and use phrases “most probably”, etc.”
    FACT CHECK: As stated in the facts above, viruses were discovered in the late 1800s. But, even if they had not by the end of the 1918-1919 pandemic, that doesn’t mean that methods for detecting the virus didn’t come along that allowed a retrospective analysis of what happened. For example, people who lived through that pandemic had higher antibody levels against H1N1 in the 2009 pandemic than others. (Source: Furthermore, the virus was recovered from bodies of victims of the 1918-1919 pandemic. (Source:
  • “The U.S. Army even acknowledges the first person to get the so-called Spanish flu (in the world) was an army cook at Ft. Riley, KS. Coincidentally from the same pathogen (Meningitis) used in the inoculations given to all the military personnel in the U.S. and around the world.”
    FACT CHECK: As stated in the facts above, the meningitis vaccine was only given to a few thousand troops at Ft. Riley, and not “to all the military personnel in the U.S. and around the world.” (Source: Those vaccinations happened in October and November of 1917. The first cases of influenza at Ft. Riley did not appear until March. (Source: That is four months post vaccination before the first influenza cases. Finally, while the first cases in the United States were reported in Kansas, there is no evidence that supports the assertion that Ft. Riley was the site of the first cases worldwide. The world was still fighting World War I, and, for strategic purposes, no country would voluntarily report that their troops were unable to fight. The first cases could have been in the United States or even Europe (Source: As COVID-19 has shown us most recently with the Omicron variant, viruses are often well on their way to other parts of the world before they are first recognized somewhere. (Omicron was first detected in South Africa, but subsequent retrospective investigations have found cases occurring in other parts of the world before the South African scientists detected it.)

The rest of the message from this particular reader devolved into accusations of conspiracies between pharmaceutical companies and governments to hurt the human population, to control the human population, or to gain profits from the lives of the human population. Those accusations will not be addressed here.

Unfortunately, people like the reader who emailed us are out there, and some of them even hold positions of power that affect public health policy. Luckily, they are in the minority in their opinions. When President Biden mandated that the federal workforce receive the COVID-19 vaccine, well over 90% of those who qualified were vaccinated. With regards to childhood vaccinations, even conservative states like Mississippi and West Virginia do not allow philosophical or religious exemptions for children who attend public schools, only medical exemptions. Thus, the anti-vaccine thinking does not permeate all of society, or even all of one segment of society. The views on science and vaccination are as diverse as the people of the United States, and the world. However, those who deny science and fight (sometimes violently) against it, are, simply put, small in number and relevance.

Author: René F. Najera, DrPH

I am the editor of the History of Vaccines site, an online project by the College of Physicians of Philadelphia. All opinions expressed on these blog posts are not necessarily those of the College or any of my employers. Check out my professional profile on LinkedIn: Feel free to follow me on Twitter: @EpiRen

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  1. Editor’s Note: The message below contains certain inaccuracies and some misinformation on vaccines. Our responses are added in brackets and bold font, [like this].


    I would like to educate you a bit more on this subject and I would also like to ask that you disclose your connections to the vaccine and pharmaceutical industries that you might have as you did not disclose those.
    [Note: The History of Vaccines funding information is openly available at, including our editorial policy.]

    I have recently watched a presentation of a video taken from the WHO summit on Vaccine safety and found that a large number of doctors who presented admitted that there are not safety protocols in place for vaccines and they are not taking steps to connect any adverse events to the vaccines in the rotation currently nor has this taken place historically. Most of the doctors admitted that there are harmful adjuvants that they must contain to drive an immune response and they have absolutely no way of knowing what harm they might cause in any one person.
    [Note: The video the reader mentions has been making the rounds in anti-vaccine circles for quite a while. Interestingly, the whole summit is not presented. Rather, select quotes are taken and shown. As with many things presented out of context, the video makes it seem like these scientists said what the reader thinks they said. They didn’t. Dr. David Gorski does a great job clarifying the misinformation here:]

    To say the science is settled and should not be reviewed discredits science in my view. We know that science is always under review. For you to promote that there is no chance that the inoculations given to soldiers before they were deployed overseas might have led to a massive infection of bacterial pneumonia is in fact not looking at the science and data on record after the soldiers received multiple vaccinations all at once and then were sent over to those countries.
    [Note: A simple re-read of the blog post makes it clear that “no chance” was not written into it. We merely mentioned that the probability is very low since the vaccine in question was given in November 1917, and the first cases at the fort appeared in March 1918. It simply does not pass the biological plausibility test.]

    Many of them were healthy prior to getting the inoculations and became sick afterward. [Note: Yes, five months afterward, of influenza.] That to me sounds like they might have had vaccine poisoning to me. [Note: Vaccine poisoning is not a medical diagnosis.] There were stated reactions that should not have occurred that had more to do with the injections they received than influenza that is totally not a deadly illness in young healthy people. [Note: Young and healthy people can and do die from influenza. In the 2019-2020 influenza season, 199 pediatric flu deaths were reported, with only 43% of them having a preexisting medical condition. While it is rare that young and otherwise healthy people die due to a respiratory condition, it does happen. It is recommended that young, healthy people with severe symptoms of a respiratory condition do not wait and seek medical care.] There is much information available on this and to use CDC and NIH as proof rather than going to the source shows where your support must come from. Most of your references are from the very agencies that hold the patents for these viruses and vaccines. [Note: Misinformation on CDC and NIH holding patents continues to be one of the most pervasive anti-vaccine talking points. The Centers for Disease Control and the National Institutes of Health are both government agencies. As such, those patents belong not to those agencies but to the people. Any profits from those patents are either reinvested in programs to protect public health or go into the general funds of the government, much in the same way that the Department of Defense has control over the designs of weapons systems.]

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