Consent Preferences
Books Health Hub Free Library Blog Podcast About Us Login

What Really Causes Influenza? Part 1

What Really Causes Influenza? Part 1

Written by Daniel Roytas (MHSc Human Nutrition), BHSc (Naturopathy), Dip. RM

Part 1 of 2 of this blog presents an overview of the studies that tried to prove a virus as the cause of influenza. Part 2 will hypothesize a number of potential causes of influenza. 

Influenza is said to be caused by one of four viruses, namely influenza A, B, C and D1, however many people might be surprised to hear that none of these viruses have ever been observed in the bodily fluids of a human being. More surprisingly, isolated and purified viral particles have never been exposed to a healthy host and been shown to cause disease2,3. This is not due to lack of trying, or due to limitations of laboratory techniques, in fact, dozens upon dozens of experiments have been undertaken over many decades to try and transmit the influenza virus from sick people to healthy people.

The Most Important Influenza Study?

At the height of the Spanish Influenza epidemic between 1918-1919, the United States Navy and United States Health Department conducted almost 30 separate experiments to try and infect over 200 healthy sailors with Spanish Influenza. This was done by exposing the healthy sailors directly to infected sailors. They coughed and spat into each other’s mouths, had mucous and other bodily fluids sprayed and dropped into their eyes, noses and mouths, and had mucous and blood from sick people injected directly into their blood streams. They even took healthy men into quarantine camps full of infected sailors. They had conversations with each other, breathed all over each other, shook each other’s hands and slept in the same beds. In not a single case, did any of the healthy sailors become ill4.

However, these are not the only experiments that were undertaken. The studies mentioned below provide an insight in to just some of the experiments undertaken (presented in chronological order) to try and prove that influenza is caused by a transmissible virus;

Failed Contagion Experiments

1906 – Davis et al. attempted to infect 1 healthy person with influenza by injecting them with nasal secretions from an individual suffering from influenza. This person did not become ill5.

1917 – Dold et al. injected healthy people with the nasal secretions taken from one ill person, 0/40 healthy people became ill6.

1918 – Nuzum et al. conducted 2 separate experiments trying to infect healthy people by spraying mucous secretions taken from one ill person into their nasal passages, 0/7 became ill7.

1918 – Selter et al. took mucous secretions from 5 people and sprayed it into the noses and mouths of 2 healthy people, 0/2 became ill8.

1918 – Nicolle et al. injected monkeys with the bronchial secretions of sick people. Blood was then taken from the monkeys and injected in to healthy human participants, 0/2 became ill9.

1919 – Michelli et al. injected healthy people with mucous from ill people in 2 separate experiments, 0/18 became ill10.

1919 – Lister et al. took a group of healthy men to a deserted island and sprayed infected mucous into their eyes, noses and mouths, 0/11 became ill11.

1919 – Yamanouchi et al. sprayed infected mucous into the noses and throats of healthy men, 0/14 became ill12.

1919 – Wahl et al. attempted to infect healthy men by dropping mucous into their mouths and noses. 0/5 became ill. Similar experiments were attempted again one year later with another group of healthy men, 0/2 became ill13.

1920 - Bloomfield exposed healthy men to mucous secretions taken from sick people, 0/14 became ill14.

1920 - Schmidt et al. conducted two controlled experiments, exposing healthy people to the bodily fluids of sick people suffering influenza. Of 196 people exposed to the mucous secretions of sick people, 21 (10.7%) developed colds and three (1.5%) developed grippe (influenza). In the second group, of the 84 healthy people exposed to mucous secretions of sick people, five (5.9%) developed grippe and four (4.7%) developed colds. Of forty-three controls who had been inoculated with sterile physiological salt solutions eight (18.6%) developed colds. A higher percentage of people got sick after being exposed to saline compared to those being exposed to the “virus”15.

1920 – Cecil et al. believed influenza was caused by a bacteria and exposed healthy men to Pfieffer’s bacillus, the bacteria many doctors believed at the time was the cause of the flu. Interestingly, all 12 healthy participants fell ill with influenza-like-illness. How is this possible when the cause of influenza is supposedly a virus?14

1921 – Williams et al. exposed healthy men to the mucous secretions of sick people suffering influenza, 0/45 became ill6.

1924 – Robertson et al. took the mucous secretions from 16 influenza patients and exposed it to healthy men, 0/100 became ill15.

1937 – Burnet et al. exposed healthy men to the influenza virus via means of inoculation. Whilst this experiment was not designed to infect participants, it is interesting that despite being exposed to the virus, 0/200 became ill.

1940 – Francis et al. exposed healthy men to the mucous taken from an infected person, 0/11 became ill.

A Word On Viral Isolation

After these experiments (and many more like them) failed to prove the transmissibility of influenza (and other infectious diseases such as measles, chicken pox and Scarlet Fever), virology became all but obsolete and was forgotten about for over a decade until John Enders landmark study in 1954. In this experiment, Enders claimed he isolated the measles virus, breathing new life in to the field of virology. However, upon closer examination of Enders’ methodology, it is plain to see that his claims of viral isolation are based upon shaky unscientific methodology and assumptions. Rather than isolating an actual viral particle, Enders exposed kidney cells to unfavourable conditions in a petri dish, by adding in toxic substances (such as antibiotics, antifungals, animal blood, trypsin) and starving the cells. When the cells died, he claimed it was due to a virus and pointed at indiscriminate particles under a microscope, claiming they were the “virus”. These particles were never isolated and exposed to a healthy host and shown to cause disease. To this day, this process is considered the “gold standard” of virus isolation and is considered proof that viruses cause disease16.

Recent Infection & Transmission Experiments

There are a number of more recent human challenge experiments, where volunteers have been experimentally infected with an influenza virus and then housed with another group of healthy volunteers, in an attempt to prove transmission. At first glance, it would seem that illness is indeed induced in the volunteers exposed to the virus and then successfully transmitted to the healthy volunteers living with them17,18, however upon closer examination, things aren’t always what they seem. There are a number of obvious issues that arise upon closer review of the methodology of these experiments.

Firstly, it is not abundantly clear if an isolated virus is being exposed to the recipients, the authors only mention that the virus was manufactured and processed under current “good manufacturing practices” (GMP). What does this mean exactly? How did they isolate the virus and why do they not disclose the “GMP” in their methodology? Are people having a toxic cell culture containing dead and dying cells, antibiotics, animal blood and other toxic chemicals sprayed up into their nasal passages (after all, this is the way a virus is supposedly isolated)? How do we know that it isn’t the act of spraying something up a person’s nose that is inducing localised symptoms and not the virus? Previous experiments have concluded that transient influenza-like symptoms (runny nose & cough) are caused by spraying various solutions into people’s nasal passages4.

Secondly, in these experiments, 0/4017 and 2/1518 people who lived with infected people, under tightly controlled experimental conditions, for several days, became ill. How is it possible that under such conditions, modern day scientists were still unable to show clear proof of viral transmission, despite all of the technological advancements that have occurred since the previous failed contagion experiments that occurred 100 years prior?

Given the lack of rigorous scientific evidence proving that influenza is indeed caused by a virus, how can anyone with a critical mind blindly accept and then take the position of a virus being the irrefutable cause of this common illness? The next question that must be answered is, if not a virus, then what is the cause of influenza? Unfortunately, because we have been so focused on a germ as the cause of disease, basically zero investigation has been undertaken to identify the true cause of what we call a “contagious viral illness”.

Stay tuned for part 2 of this blog, where the potential causes of what might be causing influenza will be hypothesized.


  1. Henritzi D, Hoffmann B, Wacheck S, et al. A newly developed tetraplex real-time RT-PCR for simultaneous screening of influenza virus types A, B, C and D. Influenza and Other Respiratory Viruses. 2019;13(1):71-82. doi:10.1111/irv.12613
  2. Cowan T, Fallon S. The Contagion Myth. Skyhorse; 2021.
  3. Engelbrecht T, Koehnlein C, de Harven E, Bailey S, Scoglio S. Virus Mania: How the Medical Industry Continually Invents Epidemics, Making Billion-Dollar Profits at Our Expense. 3rd ed. Books on demand; 2021.
  4. Rosenau MJ. Experiments to determine mode of spread of influenza. Journal of the American Medical Association. 1919;73(5):311-313. doi:10.1001/jama.1919.02610310005002
  5. Walker J. Infection of Laboratory Worker with Bacillus Influenzae. Journal of Infectious Diseases. 1928;43(4).
  6. Long P, Doull J. Etiology of Acute Upper Respiratory Infection, (Common Cold). Exp Biol Med. 1930;28(1):53-55.
  7. Nuzum JW. Pandemic Influenza And Pneumonia In A Large Civil Hospital. JAMA: The Journal of the American Medical Association. 1918;71(19):1562. doi:10.1001/jama.1918.26020450009011a
  8. Selter H. Zur Aetiologie der Influenza. DMW - Deutsche Medizinische Wochenschrift. 1918;44(34):932-933. doi:10.1055/s-0028-1134625
  9. Nicolle C, Lebailly C. Quelques notions expérimentales sur le virus de la grippe. Comptes rendus de l’Académie des Sciences. 1918;167.
  10. Michelli F, Satta G. On the etiological problem of today’s influenza pandemic. Journal of the Royal Academy of Medicine of Turin. Published online 1919:115-136.
  11. Lister F, Taylor E. Experimental Investigation of Epidemic Influenza at Durban. Public South African Inst Med Res. 1919;12(9).
  12. Yamanouchi T, Sakakami K, Iwashima S. The Infecting Agent of Influenza. The Lancet. 1919;1(971).
  13. Wahl R, George B, Lyall H. Some Experiments on the Transmission of Influenza. The Journal of Infectious Diseases. 1919;25(5).
  14. Cecil R, Steffen G. Acute Respiratory Infection in Man following Inoculation with Virulent Bacillus influenzae. The Journal of Infectious Diseases. 1921;28(3).
  15. Robertson RC, Groves RL. Experimental human inoculations with filtered nasal secretions from acute coryza. Journal of Infectious Diseases. 1924;34(4):400-406. doi:10.1093/infdis/34.4.400
  16. Enders JF, Peebles TC. Propagation in Tissue Cultures of Cytopathogenic Agents from Patients with Measles. Experimental Biology and Medicine. 1954;86(2):277-286. doi:10.3181/00379727-86-21073
  17. Nguyen-Van-Tam JS, Killingley B, Enstone J, et al. Minimal transmission in an influenza A (H3N2) human challenge-transmission model within a controlled exposure environment. PLoS pathogens. 2020;16(7):e1008704. doi:10.1371/journal.ppat.1008704
  18. Killingley B, Enstone JE, Greatorex J, et al. Use of a Human Influenza Challenge Model to Assess Person-to-Person Transmission: Proof-of-Concept Study. The Journal of Infectious Diseases. 2012;205(1):35-43. doi:10.1093/infdis/jir701



50% Complete

Please enter your details in the form below.

Join our mailing list and stay up to date with new blogs, podcasts and courses.