Authorities say about 250 immigrant children were given an adult dose of a Hepatitis A vaccine at a Texas detention facility where they are being held with their mothers.
US Immigration and Customs Enforcement spokesman Richard Rocha says health care professionals will monitor the children over the next five days for any potential side effects, though no adverse reactions are expected from the incorrect dose.
Rocha says ICE and the Department of Homeland Security's Office of Health Affairs is investigating how the mix-up at the detention center in Dilley occurred and how such mistakes can be avoided in the future.
As of Wednesday, the center about 70 miles (113 kilometers) southwest of San Antonio held about 2,000 women and children. Most are from Central American and entered the US via Mexico.
