The United States will require travelers from China to show a negative COVID-19 test result before flying to the country amid China's recent uptick in cases, the Centers for Disease Control and Prevention said Wednesday.

The big picture: The CDC's decision comes amid a surge in COVID-19 cases in China, which recently loosened its travel restrictions and opened its borders for overseas travel.

• The CDC said it is concerned about slowing the spread of COVID-19 in the U.S., citing the “lack of adequate and transparent” data about the outbreak being reported from China.
• The agency also wants to prevent any variants of concern from leaking into the country.

Details: Starting Jan. 5 at 12:01 a.m. ET, all passengers from China who are 2 years old and older will need to receive a negative PCR or antigen self-test no more than 2 days before their departure from China, Hong Kong or Macau, per the CDC.

• This applies regardless of nationality or vaccination status, the CDC said.
• It also applies to travelers traveling from China via a third country, or those who are connecting through the United States to another country.
• Airlines will need to confirm the negative test result for all passengers before they board. Otherwise, they can deny boarding for the traveler, per the CDC.

Context: People in China — who were under heavy COVID travel restrictions until earlier this month — have been flocking out of the country. Air travel ticket sales have soared since China eliminated quarantines and testing requirements for travelers into the country.

• But China is also dealing with a deadly spike in COVID-19 cases due to the elimination of nationwide restrictions.
• The CDC said the lack of accurate data coming out of the PRC will make it more difficult for federal health officials to identify variants of concern if they arise.

Worth noting: The United States isn't alone in monitoring what's happening with travelers from China.

• Italian health authorities announced they would begin testing all arrivals from China for COVID-19 after about 50% of passengers on two flights to Milan were found to be carrying the virus, per Bloomberg.
• German health authorities said they were also monitoring the situation, Bloomberg reports.

Editor's note: This story has been updated with additional details.