People receive COVID-19 test in New York, the United States, Nov. 27, 2020. (Xinhua/Wang Ying)

 The US Centers for Disease Control and Prevention (CDC) announced on Tuesday a new requirement for a negative COVID-19 test to all air passengers entering the United States.

The new order, signed by CDC Director Robert Redfield Tuesday, will become effective on Jan. 26.

"Testing before and after travel is a critical layer to slow the introduction and spread of COVID-19. This strategy is consistent with the current phase of the pandemic and more efficiently protects the health of Americans," said a statement of the CDC.

Air passengers are required to get a viral test within the three days before their flight to the United States, and provide written documentation of their laboratory test result to the airline or provide documentation of having recovered from COVID-19.

Airlines must confirm the negative test result for all passengers or documentation of recovery before they board, the new order requires.

Before departure to the United States, a required test, combined with the CDC recommendations to get tested again 3-5 days after arrival and stay home for 7 days post-travel, will help slow the spread of COVID-19 within US communities from travel-related infections, said the CDC.

Pre-departure testing with results known and acted upon before travel begins will help identify infected travelers before they board airplanes, said the agency.

The new order comes as variants of the SARS-CoV-2 virus continue to emerge in countries around the world, and there is evidence of increased transmissibility of some of these variants.

"With the US already in surge status, the testing requirement for air passengers will help slow the spread of the virus as we work to vaccinate the American public," said the CDC.

Last month, the CDC announced that all air travelers arriving in the United States from the United Kingdom would be required to test negative for COVID-19 before departure.

"Testing does not eliminate all risk," said Redfield, "but when combined with a period of staying at home and everyday precautions like wearing masks and social distancing, it can make travel safer, healthier, and more responsible by reducing spread on planes, in airports, and at destinations."

The United States has recorded more than 22.7 million COVID-19 cases with over 379,500 related deaths as of Tuesday evening, according to the real-time count kept by Johns Hopkins University.