Texas health officials reported 17 new measles cases on Tuesday, bringing the total confirmed cases since late January to 663. The state’s public health department estimates that fewer than 10 of the confirmed cases — about 1% — are “actively infectious.

The measles outbreak centered in the South Plains region of Texas grew to 663 cases on Tuesday, according to health officials. The latest update from the Texas Department of State Health Services adds 17 new cases since the agency's last update on Friday.

Among the 646 measles cases in West Texas, state health officials said 618 involved individuals who were either unvaccinated or had an unknown vaccination status. The CDC recommends two doses of measles, mumps and rubella vaccine for children 6 and younger and one or two doses for those who are older and don’t have evidence of immunity.