Washington, Jan 13 : The US Centers for Disease Control and Prevention (CDC) has announced a new requirement for a negative Covid-19 test to all air passengers entering the US. The new order, signed by CDC Director Robert Redfield on Tuesday, will become effective on January 26, Xinhua news agency reported. "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 US, 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 US, 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 travellers 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 travellers arriving in the US from the UK 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." /IANS