Study details and key findings

To understand how the brain helps prepare the body for an immune response, researchers conducted several experiments with 248 healthy participants who wore VR headsets. In each experiment, participants watched as three faces with neutral expressions repeatedly loomed toward them. The faces were of the same sex as the participants.

After this, participants were split into groups and shown the same three faces several times. Some groups saw the faces with a neutral expression, and some saw the faces with signs of viral infection, such as skin rashes. An additional subset of participants was also shown faces with fearful expressions.

In one experiment, the participants were asked to press a button when they felt a touch to their face. The researchers found that participants pressed the button faster when they felt a touch from the sick face than when they felt a touch from the neutral or fearful face.

According to the researchers, "[t]hese findings suggest an integrated neuro-immune reaction in humans toward infection threats, not solely following physical contact."

The researchers also ran EEG tests on the participants and found that the brain system that represents the space closely surrounding the body became activated as the virtual faces moved closer. However, participants' brains responded differently when they saw faces with signs of infection, with activation occurring in parts of the brain associated with detecting and filtering threats.

Commentary

According to Michael Irwin, a psychoneuroimmunologist at the University of California, Los Angeles, the study is "really remarkable" since it demonstrates that "people's immune system can be primed just by the visual recognition that someone looks sick."

Separately, Esther Diekhof from the University of Hamburg, said that the study "provides yet another good example for the existence of a mechanism that responds to potential contagion threats even before the immune system has come into contact with pathogens."

However, other health experts have noted that there are still many questions, and more research is needed to understand whether the observed responses could help the immune system fight off an infection.

"When we get infected, by Sars-CoV for instance, it can take a day or two for the infection to establish and for the immune system to become aware of it and respond, a long time after the initial encounter that stimulated this short-lived mobilization," said Benedict Seddon, a professor at University College London.

Currently, the researchers are working on furthering their study by examining whether the effects could last over hours and days and not just immediately after seeing a sick face. They also plan to monitor more cells and molecules.

Although the research is still in the early stages, the researchers say that the findings could have practical applications in the future, such as improving immune responses or the efficacy of certain drugs.

"If you have flu and take paracetamol, for instance, you could use virtual reality to boost the effect by modulating the immune system reaction," said Andrea Serino, a neuroscientist at the University of Lausanne in Switzerland and one of the study's authors.