Study Shows Seeing Sick Faces May Activate the Immune System

A recent study shows that participants who see sick-looking faces in virtual reality exhibit changes in brain activity related to personal space monitoring and threat detection, as well as an increase in the activity of certain immune cells in the blood.

In the study, 248 participants watched human-like faces approach them in virtual reality, some of which displayed clear signs of sickness such as coughing or rashes, while others appeared fearful or neutral. Those who saw sick-looking avatars entering their personal space reacted faster to their face being touched, suggesting a state of high alert. Brain imaging revealed that regions responsible for monitoring personal space reacted differently to sick faces compared with neutral or fearful ones. The salience network, a brain circuit that detects important events in the environment, was also activated, suggesting the differences were about infection, not threats in general.

In addition, blood tests revealed that participants who saw sick faces showed increased activity of innate lymphoid cells, which are one of the immune system’s first responders. “This is a completely new level of immune activation I wouldn’t have expected … without entry of a pathogen into the body,” says Camilla Jandus, MD, PhD, an immunologist at the University of Geneva.

To show these changes resembled responses to actual infections, Dr. Serino and colleagues compared the changes to responses to a flu vaccine, finding that the pattern of innate lymphoid cell activation for the vaccine was similar to participants exposed to infectious avatars. According to the researchers, the brain circuits involved may influence the immune system via the hypothalamic-pituitary-adrenal axis, a network of brain regions and glands that controls stress responses.

The discovery could eventually have practical applications such as improving vaccine 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,” says Dr. Serino.