Flu season generally starts in October and peaks in February, according to the Centers for Disease Control and Prevention, and somewhere between 5 and 20 percent of Americans get the flu every year, with hundreds of thousands hospitalized. During this time of year, many Americans with fevers, aches, and runny noses will face a question: Should they go into work?

Going to work sick isn’t preferable for workers or their colleagues. Human-resources experts say it’s a problem, as it limits individuals’ productivity and risks getting others sick too. One study pegged the cost of “presenteeism” at about $150 billion, and researchers have found that staying home usually leads to less work-time lost in the end.

Why does this persist, even for those who aren’t worried about getting their coworkers sick? According to a new report by the food-industry consultancy Alchemy (and survey conducted online by the Center for Research and Public Policy), 51 percent of food workers go to work “always” or “frequently” when they’re sick. That can’t be good for food safety, let alone for the basic health of the workers themselves.

The leading two reasons for going into work, both given by about 45 percent of respondents, were not wanting to let coworkers down and not wanting to miss out on pay. Thirty-four percent of those surveyed said they came in because they didn’t think they were contagious. (A study last year found that even those with paid sick leave feel non-financial pressures to show up. In that survey, 42 percent of workers said that they were afraid of not working while sick because too much work will pile up.)

The report also found a gap between management and workers: Of the 78 food-industry leaders surveyed, only 18 percent thought workers come to work sick—which could go some way toward explaining why so few workers in the food industry get paid sick leave (and perhaps even why about 43 million private-sector workers don’t get it either).

There are things managers can do to discourage workers from showing up while sick. One CDC study found that food workers are less likely to work while sick if there is a policy requiring workers to tell their manager about their illness. Also, people working under more-experienced managers were less likely to come in sick. Another variable is whether there’s someone to fill in for them on short notice. If employers have systems in place to make sure that a single worker’s absence won’t fall too hard on her colleagues, that could help alleviate some of this burden.