These follow an earlier evacuation of a US government employee in April who reported experiencing "subtle and vague, but abnormal, sensations of sound and pressure", according to the State Department.
For its part, China says it has no information concerning the illnesses.
Cuba said it remained ready to work with the United States to determine what, if anything, was causing the illnesses after its own investigation had uncovered no evidence of foul play.
The State Department had confirmed earlier that one USA employee assigned to the consulate in Guangzhou had "suffered a medical incident", and that it had deployed a team to screen employees and family members there.
Asked about the latest incidents, Chinese Foreign Ministry spokeswoman Hua Chunying said the US had not formally raised the matter with Beijing.
The State Department has sent a medical team to China to offer medical screenings to all American government workers and family members who want them.
The evacuated Americans have been transferred to the same facility at the University of Pennsylvania where the government workers in Cuba were sent, an unnamed USA official told The Associated Press. The U.S. government has deemed those incidents "specific attacks" on American workers but hasn't publicly identified a cause or culprit. That's where doctors have been treating and studying patients previously evacuated from the U.S. Embassy in Havana.
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In 2017 in Cuba at least 22 American diplomat and their family members have suffered as a result of the mysterious "acoustic attack".
"It appears that we have identified a new syndrome that may have important public health implications", senior author Douglas H. Smith, director of Penn's Center for Brain Injury and fix, said at the time.
Pompeo released a statement on June 5 saying the department established a task force last month "to direct a multi-agency response to the unexplained health incidents".
People working in The Canton Place complex, a few kilometers (miles) from the consulate, said Thursday they were just hearing about the incidents, reflecting a lack of coverage in China's entirely state-controlled media.
The China incidents affect one of the most important of the seven US diplomatic outposts in the country.
It serves four southern provinces with a combined population of more than 204 million and processes more than 1 million visa applications of all types annually. According to the statement, authorities could not find the source of the sound.
"For me I feel it's very odd".