The child in Meriden was tested, but didn't have the results before going to class.
He turned out to be positive.
School officials say the parents broke the district's rules.
"Despite all health guidance, the parents sent the student to school while waiting for the test results," Superintendent Mark Benigni said. "Not only does this impact this family, but also the classroom of students."
Now, the student's entire class must quarantine for 14 days.
MORE NEWS: Moving companies turn customers away as people leave Tri-State in record numbers
RELATED: New York, New Jersey, Connecticut out-of-state travelers quarantine list
MORE CORONAVIRUS COVID-19 COVERAGE
Back to school information
How coronavirus changed the New York region
Do you have coronavirus symptoms?
What's Open, What's Closed in the Tri-State area
COVID-19 Help, Information. Stimulus and Business Updates
New York City
Westchester and Hudson Valley
abc7NY Phase Tracker: