Can You Catch A Cold?: Untold History & Human Experiments

This work challenges the widespread belief that colds and influenza are caused by contagious viruses, presenting a critical review of over a century of scientific research. It analyses more than 200 human transmission studies that have largely failed to demonstrate sick-to-well transmission of respiratory illnesses. By questioning the foundations of germ theory, including Koch's postulates and virus isolation methods, the text explores alternative explanations for why people get sick, such as environmental factors, psychological phenomena like the nocebo effect, and social contagion.

The historical challenge to contagion

For centuries, diseases like scurvy and pellagra were mistakenly believed to be contagious because they affected groups of people simultaneously. It was later discovered they were caused by nutritional deficiencies. This historical precedent for misattributing the cause of illness sets the stage for a re-examination of germ theory. The theory itself emerged from a contentious debate between Louis Pasteur, who championed the idea of disease-causing airborne germs, and Antoine Béchamp, who argued that the internal environment, or "terrain," was the primary determinant of health and disease. Béchamp’s terrain theory proposed that germs were the consequence, not the cause, of a diseased state.

Critiquing the foundations of germ theory

The scientific pillars supporting germ theory are shown to be unstable. Robert Koch's postulates, the criteria used to prove a microorganism causes a specific disease, were frequently unfulfilled, even by Koch himself. This led to the creation of "rescue devices" like asymptomatic infection to explain inconsistencies. Furthermore, the process of virus isolation is critically flawed. Virologists rely on cell cultures, which are artificial environments where cytopathic (cell-killing) effects can be caused by the culture ingredients themselves, not necessarily a virus. The inability to distinguish alleged viruses from other cellular particles, like exosomes, and the artefacts created by electron microscopy, call into question whether a virus has ever been truly purified from a sick host.

A century of failed human transmission experiments

Despite the popular belief that colds and flu are easily spread, numerous attempts to prove this under controlled conditions have been unsuccessful. The most comprehensive human contagion experiments in history were conducted by the U.S. Navy and Public Health Service during the 1918 Spanish Flu pandemic, yet they consistently failed to transmit the illness.

The Spanish Flu investigations

At military quarantine hospitals on Deer Island, Angel Island, and Gallups Island, over 160 healthy volunteers were directly exposed to sick influenza patients and their bodily fluids. Researchers sprayed unfiltered mucus into their nasal passages, injected them with blood from sick donors, and had them sit face-to-face with coughing patients. Across dozens of experiments, only a handful of men developed mild symptoms, resulting in a transmission rate of less than 2%. These results were baffling to the investigators, who could not explain the failure to transmit what was considered the most infectious disease in modern history.

The Common Cold Research Unit (CCRU)

From 1946 to 1989, the UK's Common Cold Research Unit (CCRU) conducted extensive research involving thousands of volunteers. Their experiments also struggled to demonstrate contagion. In one series of trials, only two out of 25 healthy people (8%) developed colds after being confined in a room with sick individuals who were actively coughing and sneezing. Even when they achieved higher "infection" rates using concentrated cell culture fluids, the results were confounded by a lack of adequate controls. Notably, experiments showed that inoculating volunteers with sterile saline solution could induce cold symptoms in up to 19% of participants, highlighting the powerful role of the nocebo effect and mechanical irritation.

Alternative explanations for illness

If not from contagious germs, how do people get sick? Alternative models propose that illness can arise from psychological and environmental factors that disrupt the body's natural balance.

Social and psychological contagion

The nocebo effect, where the expectation of harm leads to negative symptoms, is a powerful and documented phenomenon. Studies have shown that individuals can develop cold and flu symptoms simply by believing they have been exposed to a pathogen. This psychological response can spread through social contagion, leading to outbreaks of mass psychogenic illness, where symptoms manifest across a group without any biological cause. This offers a non-microbial explanation for why people in close contact often fall ill together.

Environmental and toxicological factors

Environmental conditions play a significant role in respiratory health. Changes in temperature and humidity are strongly correlated with flu outbreaks. Furthermore, exposure to air pollution and environmental toxins is known to produce influenza-like symptoms. The "pH hypothesis" suggests that inhaling pollutants or consuming an acid-forming diet can lower the pH of airway fluid, impairing the body's natural defences and causing inflammation and tissue damage. From this perspective, a cold or flu may not be an infection but rather a detoxification process initiated by the body to clear accumulated toxins and restore homeostasis.