Here’s something that will make you lose just a bit more faith in humanity—or at least reach for some hand wipes. New research shows that even in hospitals, a substantial number of people aren’t bothering to wash their hands.

Scientists from the University of Surrey in England led the study, installing sensors near hospital toilet and sink pipes to keep track of people’s handwashing. Nearly half of toilet users skipped the sink after flushing, they found. The researchers say more effective strategies are needed to remind and convince people of the importance of handwashing, particularly in high-risk environments like hospitals.

Previous studies have tried to analyze how rigorous people are about handwashing in hospitals and other settings, but they’ve been limited. Some have relied on asking people to self-report their hygiene habits, for instance, which might incentivize more than a few to fudge the truth. The researchers decided to take a different approach. They connected sensors to toilet and sink pipes that could objectively and non-intrusively detect if and when they were being used. The sensors work by measuring the temperature in the pipes and nearby air; when either cold or hot water passes through the pipes, the temperature sharply changes relative to its surroundings, indicating use.

The researchers teamed up with the Bispebjerg Hospital in Denmark to conduct their study (aptly named the “FLUSH. WASH. PROTECT.” study). For 19 weeks, they tracked people’s handwashing behaviors at two public restrooms in the hospital, ultimately recording more than 2,600 flushes. Nearly 44% of the time after flushing, people steered clear of handwashing. At times, non-adherence was even worse, with over 60% of people not handwashing during certain weeks. Non-handwashing was also more common at the start and end of the day and during typical meal times. The team released its findings last week on the Open Source Framework.

“People may assume handwashing is second nature by now—especially in hospitals and post-covid-19—but our data paints a different picture,” said lead author Pablo Pereira-Doel, co-leader of the Human Insight Lab at the University of Surrey’s Business School, in a statement from the university.

Low rates of handwashing can, of course, make it easier for doctors, patients, and visitors to inadvertently spread dangerous infections to already vulnerable people, including drug-resistant superbugs. Some studies have suggested that certain interventions, like clear signs, can modestly boost handwashing at hospitals, at least temporarily. But given the results here, it’s likely we’ll need to do a lot more to consistently improve people’s hand hygiene.

“These findings are worrying but not surprising. Even simple behaviors like handwashing can lapse without reinforcement. In hospitals, lapses like these can have serious consequences—for patients and for the wider healthcare system. It’s time we moved beyond posters and hand gel stations to more effective behavioral strategies,” said study author Carrie Newlands, Lead for Clinical Skills at the University of Surrey’s School of Medicine, in a statement.

In the meantime, I wouldn’t blame you (or myself) for avoiding the standard handshake more often. And just in case anyone needs it, here’s the proper technique for handwashing, courtesy of the Centers for Disease Control and Prevention.