The number of cases reported in Texas' historic measles outbreak has risen to 663 cases in 26 counties, as of April 29. Of those, 87 patients have been hospitalized, and two school-aged children have died since the outbreak began in January.

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 Texas health department reported 663 cases of measles in the state on Tuesday, an increase of 17 cases since April 25, as the U.S. battles one of its worst outbreaks of the childhood disease.