California health officials continue their investigation into an E. coli outbreak that has sickened at least a dozen people in the Bakersfield, California, area.

A common thread is a restaurant in Bakersfield, but the Kern County Health Department will not reveal its location. Health officials continued to say there is no immediate threat to the public and that is why the health department will not officially name the pizzeria.

Two of the hospitalized children have been released, and two developed hemolytic-uremic syndrome — a condition marked by kidney failure and seen in serious foodborne illnesses — and were transferred to hospitals outside Kern County.