Up to 75% of people say they've hidden illnesses, raising risks

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Kentucky Health News

A startling number of people conceal an infectious illness to avoid missing work, travel, or social events, the University of Michigan says in reporting on research conducted there.

The findings were published in Psychological Science, a journal of the Association for Psychological Science, and announced in a university news release.

Reserachers did a series of studies involving healthy and sick adults and found that 75% of the 4,110 participants said they had either hidden an infectious illness from others at least once or might do so in the future. Many of them reported boarding flights, going on dates, and making other social interactions while secretly sick.

More than 61% of health-care workers in the studies said they had concealed an infectious illness.

The research report is titled “When and why people conceal infectious disease.” The researchers found a difference between how people believe they would act when ill and how they actually behave, said Wilson N. Merrell, a Ph.D. candidate at Michigan and the lead author on the study.

“Healthy people forecasted that they would be unlikely to hide harmful illnesses—those that spread easily and have severe symptoms—but actively sick people reported high levels of concealment regardless of how harmful their illness was to others,” Merrell said.

In the first study, Merrell and his colleagues recruited 399 university health-care employees and 505 students who reported the number of days they felt symptoms of an infectious illness, starting in March 2020, when the Covid-19 pandemic began. They then reported how often they actively concealed symptoms, came to campus or work without telling anyone they were feeling ill, or falsified mandatory symptom screeners that the university had required for anyone using campus facilities.

More than 70% of the participants reported concealing their symptoms. Many said they hid their illness because it would conflict with social plans, while a small percentage cited pressure from institutional policies such as lack of paid leave. Only five participants reported hiding a Covid-19 infection.

In a second study, the researchers recruited 946 participants online and randomly assigned them to one of nine conditions in which they imagined being either moderately or severely sick while in a social situation. In each condition, the risk of spreading the illness was designated as low, medium, or high. To control for the special stigma associated with Covid-19 at the time, the researchers asked participants not to imagine being sick with that disease. Participants were most likely to envision themselves hiding their sickness when symptom severity was low, and least likely to conceal when symptoms were severe and highly communicable.

In another study, Merrell and colleagues used an online research tool to recruit 900 people—including some who were actively sick—and asked them to rate the transmissibility of their real or imagined illness. The participants were also asked to rate their likelihood of covering up an illness in a hypothetical meeting with another person. The actively ill were more likely to conceal their illness than those who just imagined being sick, regardless of the illness's transmissibility.

“This suggests that sick people and healthy people evaluate the consequences of concealment in different ways, with sick people being relatively insensitive to how spreadable and severe their illness may be for others,” Merrell said.

The Covid-19 crisis may have shaped the way the participants thought about concealing an illness, Merrell said, adding that future research could explore how ecological factors such as pandemics and medical advances such as vaccines influence people’s disease-related behavior.

Merrell said, “People tend to react negatively to, find less attractive, and steer clear of, people who are sick with infectious illness. It therefore makes sense that we may take steps to cover up our sickness in social situations. This suggests that solutions to the problem of disease concealment may need to rely on more than just individual good will.”