Using evolution to think about the pandemic suggests SARS-CoV-2 can affect social behaviors

An ensemble of scientists, with expertise in psychology, biology, neuroscience and medicine, has authored a paper that uses an evolutionary perspective to interpret and assess the COVID-19 pandemic. The novel SARS-CoV-2 virus has infected more than 40 million people and killed more than 1 million worldwide. It has also severely impacted the global economy. 

The paper, which published on Oct. 22 in Proceedings of the National Academy of Sciences, includes 10 insights about the pandemic. Athena Aktipis, associate professor of psychology at Arizona State University, and Joe Alcock, professor in the Department of Emergency Medicine at the University of New Mexico, co-authored the first insight about how the virus might affect social behavior in people. 

“Evolutionary theory can be used at many levels to understand what is going on with the COVID-19 pandemic, from how cells interact to the effect on society and culture,” Aktipis said. “Viruses and other agents of infection are known to affect the social behavior of their hosts by suppressing feelings of sickness during the highest periods of contagiousness, so we applied this line of thinking to SARS-CoV-2.”  

One way a virus can make people feel well when they are most contagious is by altering the immune system response. The SARS-CoV-2 virus interferes with immune system proteins called interferons that coordinate the body’s response to the virus. 

“Interferon is thought to cause social withdrawal and other sickness behaviors when we become ill,” Alcock said. “By blocking interferon, it is possible that the SARS-CoV-2 virus manipulates our behavior and keeps us interacting with other people, which is good for viral transmission — but not for us and especially not for public health.”

Another way a virus can affect social behavior is by targeting the brain. The SARS-CoV-2 virus has sometimes been found in spinal fluid, which means it can likely cross the blood-brain barrier and directly affect the brain and nervous system. It also alters how people feel pain and has caused some form of neurological dysfunction, including headaches, dizziness and even damaged brain tissue, in almost a third of patients hospitalized with COVID-19.

“We do not know whether the effect of SARS-CoV-2 on the brain is an adaptation of the virus or if it is a byproduct of how the virus evades the immune system in general. The neurological symptoms of COVID-19 could be a physiological response of the host to the infection, but based on circumstantial evidence, it is possible that this virus is manipulating behavior to make us not feel sick and act more social,” Aktipis said.

Athena Aktipis

An odorless smoking gun 

There are many symptoms of infection with SARS-CoV-2, but the loss of smell and taste stood out to Aktipis and Alcock as a “smoking gun” that this virus might be an infectious agent capable of manipulating human behavior. Other agents of infection that affect the sense of smell have also been connected to changes in behavior. An example of such an infectious agent is Toxoplasma gondii. This parasite, which has been shown to change how people make decisions, is common in cat feces and is responsible for the disease toxoplasmosis.

“Because the SARS-CoV-2 virus, like every infectious agent, is evolving to meet its own evolutionary goals, we need to consider that it might be changing how we feel in ways to help us transmit the virus. Infectious agents can influence our emotions and behavior, and we should explore whether SARS-CoV-2 is hijacking our behavior to promote transmission,” Aktipis said. “We might not like it, but the fact is we are not always in the driver’s seat. We need to know whether this virus affects our social behavior so we can better predict the spread of the pandemic and determine how to contain and manage it.”