Airport passenger screening for coronavirus during the early stages of the pandemic was futile because people can transmit the virus without showing symptoms, the United States' top health agency said on Monday.
The analysis by the Centers for Disease Control and Prevention (CDC) was published days after a news report that the White House is pushing to return to the strategy as it seeks to re-open the hard-hit airline industry.
Internal emails obtained by USA Today on Saturday showed CDC officials urging President Donald Trump's administration to reconsider the plan for fever checks as a means to restore confidence.
The US began screening passengers arriving from China on February 3, interviewing them about possible symptoms and using thermal scanners to take their temperatures, with the policy later widened to include Iran.
Since the bulk of early cases in the US came from the West Coast, the CDC's report focused on screening efforts in California.
Officials screened about 12,000 passengers between February 3 and March 17, giving them instructions on self monitoring.
But only three of these passengers were later found to match with the 26,182 patients with Covid-19 reported to California by April 15.
This suggests the efforts, despite requiring 1,694 person-hours of work, were a near-complete failure.
"The benefits of screening for case detection at the airport might be limited for a respiratory disease with the potential for pre-symptomatic and asymptomatic transmission, such as Covid-19," the reports' authors wrote.
By contrast, airport screening for Ebola during the 2014-15 outbreak was more effective because the disease "has obvious clinical manifestations, is contagious only after symptom onset, and a smaller number of travellers required monitoring," the report said.
According to the USA Today report, the White House is seeking to revive the policy of checking travellers for fever at 20 US airports.
Trump's chief of staff Mark Meadows said the effort would be visible and would instil confidence in travellers, according to meeting notes cited by the newspaper.
But Martin Cetron, the CDC's director of global mitigation and quarantine, pushed back, the paper said.
"Thermal scanning as proposed is a poorly designed control and detection strategy as we have learned very clearly," he wrote in an email to Department of Homeland Security officials. "We should be concentrating our CDC resources where there is impact and a probability of mission success."
The mooted plan would see passengers with fever referred to the CDC, with Cetron questioning the agency's authority to execute this plan. He ended his email: "Please kindly strike out CDC from this role."
Major US airline 'likely to collapse'
Meanwhile, Boeing's chief executive said it was "most likely" that a major US airline will go out of business due to the massive damage of the pandemic on the aviation industry.
"It's most likely," Boeing CEO David Calhoun responded when an NBC journalist asked him if a major US carrier will go under.
Calhoun's answer, released in a clip on Monday, is part of a longer interview that will be broadcast on Tuesday.
"You know something will happen in September," Calhoun said. "Traffic levels will not be back to a 100%, they won't even be back to 25%."
Boeing itself is suffering as the global air transport industry is brought to its knees by travel restrictions and confinement measures aimed at stopping the spread of Covid-19.
"Maybe by the end of the year we approach 50(%), so there will definitively be adjustments that have to be made on the part of the airlines," Calhoun added.
$1-billion rescue plan for Garuda
In other aviation news, Indonesia is drawing up a $1-billion rescue plan for struggling national airline Garuda after the coronavirus forced the company to ground most of its planes, AFP reported, citing Bloomberg News on Monday.
Under the plan, some $500 million in Garuda debt would be restructured with another $500 million in new loans to help the airline meet operational needs for the next six months, the report said, quoting Deputy State-Owned Enterprises Minister Kartika Wirjoatmodjo.
The company was facing the prospect of defaulting on Islamic bonds known as sukuk due next month, it said. Investors would be offered the option of extending maturities on their investment by three years or a staggered repayment scheme.
"Garuda remains a good company with bright prospects," Wirjoatmodjo was quoted as saying. "Its business will remain robust after the outbreak ends."
In a reply via WhatsApp, Garuda's president director Irfan Setiaputra said: "This is still an ongoing discussion. It's not confirmed yet."
State-controlled Garuda – which has a fleet of more than 200 aircraft with its Citilink subsidiary – has temporarily cut salaries to help cope with a travel slump sparked by the global pandemic.