No one expects to leave their doctor's appointment sicker than when they walked in. Yet new research from the University of Minnesota School of Public Health, Harvard University and athenahealth, Inc. provides new evidence about respiratory infection transmission happening within physician offices.

Published in Health Affairs, the study compared patients who visited their primary care physician before and after someone else with influenza had been in the office. The research team found that patients visiting after a flu patient were more likely to get the flu themselves.

"It's a widely accepted fact that patients can acquire infections in hospital settings, but we show that infection transmission can happen when you visit your doctor's office too," said study author Hannah Neprash, an assistant professor in the School of Public Health, noting that this is the first study to document a relationship between influenza and visit timing among a national sample of adult primary care visits.

The study used a combination of all-payer insurance claims and electronic health record data from athenahealth, Inc. to identify exposed patients—or those with an appointment occurring after a flu patient had been to the same practice.  Then, the researchers compared the likelihood that they contracted the flu versus unexposed patients.

Adjusting for patient characteristics, practice characteristics, and time of day, the study found that:

• compared to unexposed patients, patients exposed to the flu at their primary care physician's office were 31.8% more likely than unexposed patients to revisit with the flu within two weeks; and
• no similar patterns were found for urinary tract infections or back pain—two noncontagious conditions.

"Our findings highlight the importance of infection control practices and continued access to telemedicine services, as health care begins to return to pre-pandemic patterns," said Neprash. "In-person outpatient care for influenza may promote nontrivial transmission of these viruses. This may be true for other endemic respiratory illnesses too, including COVID-19, but more research is needed."

In response to the pandemic, many temporary policies were introduced to encourage the use of telemedicine services, including offering increased payment to providers who offer them. As the future of telemedicine policy is debated, researchers say that the study suggests that telemedicine is important for infection control and should remain a financially viable option for clinicians to provide care for viral respiratory symptoms.