Two of the four cases are in Lubbock, which hasn’t seen a case in more than 20 years. Measles vaccination rates in Texas have fallen over the last four years.

Two cases of measles have been confirmed in school-aged children in West Texas less than two weeks after the highly contagious respiratory illness was also reported in a pair of Houston residents. The children are residents of Gaines County who have not received the vaccine that protects against measles,

Two school-age children from Gaines County who had measles were hospitalized in Lubbock, state officials said.

Texas reports a minor measles outbreak due to low vaccination rates. Health officials urge vaccinations to prevent the spread.

Two cases were reported in Harris County, and an additional two were in Lubbock, according to The Texas Tribune.