New study indicates that many people will conceal their illnesses, putting others at risk

Have you ever hidden the fact that you were sick with a contagious illness from people around you?

Perhaps you stifled a cough during a work meeting or neglected to mention your scratchy throat on a first date. If you admitted to any such concealment behaviors, you certainly aren’t alone, according to a new University of Michigan study.

People sick with infectious illnesses face negative social outcomes, like exclusion, and may take steps to conceal their situation from others, the study indicated.

“These findings highlight the trade-offs people make between societally normative motives (like honesty, not harming others) and personally desirable motives (like pursuing one’s own goals, not worrying others),” said lead author Wilson Merrell, U-M doctoral student in psychology, who collaborated on the study with fellow graduate student Soyeon Choi and Joshua Ackerman, professor of psychology.

The researchers analyzed data from 10 studies of past, current and projected illness, examining the prevalence and predictors of infection concealment in more than 4,100 U.S. university students, health care employees and online crowdsourced workers.

About 75% of participants reported concealing illness in interpersonal interactions, possibly placing others in harm’s way. Among health care employees, 61% kept quiet, took active steps to cover up, incorrectly used a mandatory app-based symptom screener at least once in the past, or held intentions to conceal at some point in the future.

Merrell said concealment motivations were largely social—such as wanting to attend events like parties—and achievement-oriented, such as completing work objectives. In contrast, very few participants mentioned explicit institutional policies (like lack of paid time off) as primary drivers of their concealment.

“Disease concealment appears to be a widely prevalent behavior by which concealers trade off risks to others in favor of their own social goals, creating potentially important public health consequences,” Merrell said.

Disease characteristics, including potential harm and illness immediacy, also influenced concealment decisions, the researchers said. Healthy people predicted 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.

“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.

Institutions have tried to encourage honest reporting of sickness. During the COVID-19 pandemic, some universities mandated that students complete an app-based symptom screening tool to enter campus buildings. In one of the studies, researchers asked college students how often and accurately they completed the screening tool when they felt sick. About 41% reported misuse of this screener in attempts to conceal their illness when they weren’t feeling well, researchers said.

“This suggests that solutions to the problem of disease concealment may need to rely on more than just individual goodwill,” Merrell said.