DENVER (CBS4) – More than 200 students called in sick to school Friday.

On Thursday, more than 30 kids were sent home from Oakland Elementary School after displaying symptoms of norovirus.

READ MORE: Female Bicyclist Killed By Car In Lakewood, Driver Arrested For Impaired Driving

“Denver Environmental Health has instructed us to do a thorough scrub down of the entire school,” Denver Public Schools Director of Media Relations Will Jones said Thursday. “We’re doing everything we can to make sure the entire school is safe, that the entire school is clean, and we’re taking the precautions to make sure any child who has not been infected doesn’t get infected.”

The school will be sanitized again on Saturday.

Health inspectors will return on Monday to see how things are going.

READ MORE: Alleged U.S. Capitol Rioter Patrick Montgomery Faces Arrest After Hunting Mountain Lion

The Centers for Disease Control and Prevention describes norovirus as a very contagious disease that leaves patients with stomach pain and nausea.

[graphiq id=”71s4e8nFD3D” title=”Norovirus” width=”600″ height=”748″ url=”https://w.graphiq.com/w/71s4e8nFD3D” link_text=”Graphiq” ]

You can get it from an infected person or by touching contaminated surfaces.

Health officials advise any students with symptoms to wait 48 hours before returning back to school.

MORE NEWS: Michael Curran Arrested For Stealing Jeep With 1-Year-Old Child Inside

A CBS4 viewer first tipped CBS4 off to the outbreak of the illness.