The U.S. has seen three measles outbreaks since the start of the year, including one in the South Plains region of Texas. Some 223 cases have been reported since late January, the Texas Department of State Health Services said Tuesday, including one fatality in a school-age girl who wasn’t vaccinated.

HHS Secretary Robert F. Kennedy Jr. has said that contracting measles is the best defense against the disease - as an outbreak spreads across the U.S.