ATHENS – The 12 passengers on a Qatar Airways flight quarantined after testing positive for the COVID-19 Coronavirus at Athens' international airport showed no signs when they were checked in Doha before leaving, airline officials said.

Greece suspended all flights from Qatar after the tests picked up the virus in the passengers as the New Democracy government said it would allow tourists from all countries, including those hardest hit by the pandemic.

The airline said that the 12 infected passengers were not from Qatar. Nine are from Pakistan city of Gujrat and have Greek residency permits, two were Greek-Australians and the other was a Greek coming from Japan, the General Secretariat for Civil Protection said in a press release.

“When they arrived in Doha and before boarding the flight to Athens, all passengers were tested according to the procedures and established health protocols and were found fit to continue their journey,” Qatar Airlines said. 

There was no explanation how they came down with the virus during the 4 hour and 40-minute flight as airlines say the totally disinfect aircraft and air coming into the cabin is filtered.

Greece's Civil Protection Ministry suspended air links to and from Qatar until June 15, which it is allowing more air traffic to begin landing in a hope to salvage what's left of the summer tourism season.

“We knew there would be such cases. We’ve seen what can happen this summer,” said Prof Nikolaos Sipsas, an expert in infectious diseases. He told Greece's ANT1 TV that the incident highlighted the degree to which opening up to tourism was a calculated risk that had to be taken.

“The safest (thing) would be not to open up to tourism but that would mean huge economic destruction,” said Sipsas, who sits on the specialist committee advising the Greek government on management of the pandemic. 

“The first thing we have to do is divide countries of origin into safe and unsafe (categories.) That creates certain diplomatic pressure, but for us the first priority is public health,” he added.

Greece said it would cover the costs of tourists who tested positive for the virus, following the lead of Cyprus as an incentive to lure visitors. “Our aim is to ensure the maximum safety for residents and visitors,” said Stelios Petsas, the New Democracy government spokesman.