The Centers for Disease Control and Prevention reported 800 confirmed cases of measles in the U.S. as of Friday, making the announcement as the highly contagious illness has reached half of the country—though most cases remain focused in Texas.

Measles cases in Texas rise to 561, with a focus on the impact in Gaines County and the importance of vaccination.

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.