While the agency stressed that increased screening was most likely behind much of the increase, the health secretary, Robert F. Kennedy Jr., called it an “epidemic.”

The percentage of American children estimated to have autism spectrum disorder increased in 2022, continuing a long-running trend, according to data released on Tuesday by the Centers for Disease Control and Prevention.

Among 8-year-olds, one in 31 were found to have autism in 2022, compared with 1 in 36 in 2020. That rate is nearly five times as high as the figure in 2000, when the agency first began collecting data.

The health agency noted that the increase was most likely being driven by better awareness and screening, not necessarily because autism itself was becoming more common.

That diverged sharply from the rhetoric of the nation’s health secretary, Robert F. Kennedy Jr., who on Tuesday said, “The autism epidemic is running rampant.”

Mr. Kennedy has repeatedly tried to connect rising autism rates with vaccines, despite dozens of studies over decades that failed to establish such a link. The health secretary nonetheless has initiated a federal study that will revisit the possibility and has hired a well-known vaccine skeptic to oversee the effort.

Mr. Kennedy recently announced an effort by the Department of Health and Human Services to pinpoint the “origins of the epidemic” by September, an initiative that was greeted with skepticism by many autism experts.