As flu season continues in Chicago, some hospitals are reinstating mask mandates on site.

All three Rush hospitals — including Rush University Medical Center, Rush Copley Medical Center and Rush Oak Park Hospital — are again requiring patients, visitors and staff to wear masks on site.

As of this week, masks are mandatory for everyone at registration and in patient waiting rooms, along with other parts of each hospital.

“We reinstituted masking primarily because of the fairly dramatic increase in influenza in the last two or three weeks,” said Dr. John Segreti, medical director of infection control and prevention at Rush. “Influenza numbers are going up pretty dramatically. The numbers for COVID are going up slightly. Hospitalizations are going up.”

For hospital systems like Rush, bringing back mask policies is a low-cost way to keep patients and staff from transmitting respiratory viruses to each other, Segreti said.

“If you wear a mask for protection, there’s evidence that it works,” Segreti said. “It may not add very much, but it probably does help to prevent transmission if you’re not infected.”

Segreti recommends that residents resume masking indoors throughout their daily lives, especially in poorly ventilated rooms.

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Currently, NorthShore University Health System requires masking for patients with symptoms of respiratory viruses, and recommends everyone else mask up in patient care areas regardless.

Northwestern Medicine clinics and hospitals also require patients wear a mask if they have symptoms of a respiratory virus. Patients and staff can also ask each other to wear a mask while doctors are in a patient’s room.

Flu and COVID vaccination rates have been low this year, Segreti said. Staying up to date on vaccinations is especially important if you’re older, immunocompromised or experiencing comorbidities like heart or lung disease.

The Chicago COVID-19 risk factor rose to medium this week, for the first time in a year. About 34 patients per day are being hospitalized with complications related to COVID.

“You can’t tell COVID from flu from RSV just based on symptoms,” Segreti said. “You really have to get tested to be able to differentiate those.

Though influenza cases are rising, along with COVID cases to a lesser extent, RSV cases are becoming less common, Segreti said. Still, Rush’s mask policy is meant to work against all three respiratory conditions, as well as others with similar symptoms.

Segreti expects flu season to last another 4 to 8 weeks.