Dutch health authorities said Saturday they had detected 61 COVID-19 cases among people who flew Friday from South Africa and were now doing further tests to see whether any are infected with the new omicron variant.
The cases were discovered among around 600 passengers who arrived at Amsterdam's Schiphol Airport on two flights Friday before the Dutch government halted air traffic from southern Africa due to concerns over the variant.
Dutch health authorities said Saturday they also would seek to contact travelers who had arrived from South Africa, Botswana, Eswatini, Lesotho, Mozambique, Namibia and Zimbabwe since Monday and urge them to take a test as soon as possible.
The passengers from Friday's flights were kept separated from other travelers and those who tested positive are being kept in isolation at a hotel near the airport.
A spokesperson for the health ministry said it would not be known until later Saturday whether any of passengers are infected with the new variant.
A spokesperson for KLM, the Dutch arm of Air France, said the airline was trying to determine what rules were in place as of Friday morning to prevent people with COVID-19 infections from boarding the flights, which departed from Cape Town and Johannesburg.
Rules on the company's website said passengers had to present a negative COVID-19 "rapid antigen" test result taken 24 hours before departure but were not required to show proof of vaccination.
Paula Zimmerman, a Dutch photographer who returned from a family visit in South Africa on Friday morning, said the situation for the passengers on the planes was chaotic, as they were kept waiting on the tarmac and in the terminal for hours.
Zimmerman was told she had tested negative at 4 a.m., almost 18 hours after landing in Amsterdam, but said she then found out she was standing right next to a man who knew he had tested positive for an infection.
"It was really weird. There was no coordination. There were too few people and there really wasn’t anybody who took control."
Having spent hours on a flight that likely had many infected passengers made Zimmerman anxious for the days to come, she said.
"I’ve been told that they expect that a lot more people will test positive after five days. It's a little scary the idea that you've been in a plane with a lot of people who tested positive."
The Dutch flight ban does not mean that all flights from southern Africa to the Netherlands are halted, as Dutch citizens are allowed to return home, while EU citizens are allowed entry in transit to their home countries.
Medical staff, airline crews and people with pressing needs are also still allowed to travel. KLM will continue flights to the region, but travelers need to stay in quarantine for at least five days upon arrival in the Netherlands.
The new variant has been detected just as many European countries are grappling with a surge in coronavirus cases.
The Dutch government on Friday announced the nighttime closure of bars, restaurants and most stores as it tries to curb a record-breaking wave of COVID-19 cases that is swamping its health care system.