Two Oregon health officials have issued a warning to parents after a 14-year-old boy with autism started exhibiting symptoms in the weeks after he received the shots.

A review of his health history shows he began experiencing severe anxiety and social withdrawal, and his symptoms worsened, the health authority said Friday.

He had been hospitalized several times for other health issues and missed school for more than a year.

Oregon health officials also say the shots have caused significant harm to other children and to others who may have been exposed.

The boy is one of thousands of Oregon children who have been immunized, and the state’s vaccination rates have dropped dramatically over the last decade, with a sharp drop in 2015 and a sharp increase in 2016.

In the first two weeks of the year, the Oregon health authority received more than 5,000 calls from parents worried about their children, which was about one-third of the agency’s total calls for a vaccine, according to a release.