State health officials reported 4,152 new cases of COVID-19 in Oklahoma Thursday, the highest single-day caseload since January. Health Commissioner Colonel Lance Frye says the recent increase in cases is concerning and could be the effect of students returning to the classroom. There are more than 21-thousand active cases of the virus in the state, with about 16-hundred patients in Oklahoma hospitals. Frye said more than 93% of Oklahomans hospitalized with COVID in the past month are unvaccinated.