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,

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

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