A Texas measles outbreak has doubled in the last week to 124 cases, state health officials said Tuesday, a day after they warned a person infected with the highly contagious disease had traveled from the outbreak zone.

According to the society, the last US measles death was in 2015. A measles infection can have particularly devastating complications for pregnant women and young children, including pneumonia, neurological impairment, hearing loss and death.

At least 124 cases of measles have been identified in Texas since late January, mostly among children and teenagers who are either unvaccinated or whose vaccination status is unknown, officials say.