A day care facility in a Texas county that’s part of the measles outbreak has multiple cases, including children too young to be fully vaccinated, public health officials say.

At least six children at a day care in Lubbock, Texas, tested positive for measles amid the state's growing outbreak, local officials confirmed to CBS News Tuesday. On Monday, Lubbock Public Health issued immunization recommendations for the whole county following the cases at Tiny Tots U Learning Academy on South University Avenue.

The number of measles cases exceeded 500 in Texas on Tuesday, according to the state’s health department, which made the update days after a second Texas child died after contracting the highly contagious illness that has been confirmed in at least 20 states.