The Netherlands confirmed 13 cases of the new Omicron variant of the coronavirus and Australia found two as the countries half a world apart became the latest to detect it in travellers arriving from southern Africa.
Israel decided to bar entry to foreigners and Morocco said it would suspend all incoming flights for two weeks starting Monday — the most drastic of a growing raft of travel curbs being imposed by nations around the world as they scramble to slow the variant's spread, just days after it was identified by researchers in South Africa.
The "act first, ask questions later" approach reflected growing alarm about the emergence of a potentially more contagious variant that some feared could prolong a pandemic that has killed more than 5 million people.
But many experts cautioned that so much was still unknown about the new strain — and the World Health Organisation called for borders to remain open, noting that closing them often has a limited effect.
Dr Francis Collins, director of the National Institutes of Health in the United States, emphasised that there is no data yet that suggests the new variant causes more serious illness than previous Covid-19 variants. It is also not yet known whether it is more resistant to protection provided by the vaccines.
"I do think it's more contagious when you look at how rapidly it spread through multiple districts in South Africa. It has the earmarks therefore of being particularly likely to spread from one person to another. … What we don't know is whether it can compete with delta," Collins said on CNN's State of the Union.
Collins said the news should make everyone redouble their efforts to use the tools the world already has, including vaccinations, booster shots and measures such as mask-wearing.
The Dutch public health authority confirmed that 13 people who arrived from South Africa on Friday have so far tested positive for omicron. They were among 61 people who tested positive for the virus after arriving on the last two flights to Amsterdam's Schiphol airport before a flight ban was implemented. They were immediately put into isolation, most at a nearby hotel.
Authorities in Australia said two travellers who arrived in Sydney from Africa became the first in the country to test positive for the new variant. Arrivals from nine African countries are now required to quarantine in a hotel upon arrival. Two German states reported a total of three cases in returning travellers over the weekend.
Israel moved to ban entry by foreigners and mandate quarantine for all Israelis arriving from abroad.
"Restrictions on the country's borders is not an easy step, but it's a temporary and necessary step," Prime Minister Naftali Bennett said at the start of the weekly Cabinet meeting.
Dr Ran Balicer, head of the government's advisory panel on Covid-19, told Israel's Kan public radio that the new measures were necessary amid the "fog of war" surrounding the new variant, saying it was "better to act early and strictly" to prevent its spread.
Morocco's Foreign Ministry tweeted that all incoming air travel to the North African country would be suspended to "preserve the achievements realized by Morocco in the fight against the pandemic, and to protect the health of citizens." Morocco has been at the forefront of vaccinations in Africa, and kept its borders closed for months in 2020 because of the pandemic.
The United States' top infectious diseases expert, Dr Anthony Fauci, said he wouldn't be surprised if the Omicron variant was already in the US, though it hasn't yet been detected there.
The US plans to ban travel from South Africa and seven other southern African countries starting Monday. "It's going to give us a period of time to enhance our preparedness," Fauci said of the ban on ABC's This Week.
Dutch Health Minister Hugo de Jonge said he asked his country's public health institute for advice on whether additional travel restrictions are needed, but he wants to coordinate with his European Union counterparts.
Many other countries have already restricted or banned travel from various southern African countries — among the latest to do so were New Zealand, Thailand, Indonesia, Singapore, Saudi Arabia, the United Arab Emirates.
This goes against the advice of the WHO, which has warned against any overreaction before the variant is thoroughly studied.
South Africa's government responded angrily to the travel bans, which it said are "akin to punishing South Africa for its advanced genomic sequencing and the ability to detect new variants quicker". It said it will try to persuade countries that imposed them to reconsider.
The WHO sent out a statement saying that it "stands with African nations" and called for borders to stay open.
"Travel restrictions may play a role in slightly reducing the spread of Covid-19 but place a heavy burden on lives and livelihoods.
"If restrictions are implemented, they should not be unnecessarily invasive or intrusive, and should be scientifically based," it said.
In Europe, much of which already has been struggling with a sharp increase in cases over recent weeks, officials were on guard.
The UK tightened rules on mask-wearing and on testing of international arrivals after finding two Omicron cases, but British Health Secretary Sajid Javid said the government was nowhere near reinstituting work from home or more severe social-distancing measures.
"We know now those types of measures do carry a very heavy price, both economically, socially, in terms of non-Covid health outcomes such as impact on mental health," he told Sky News.
Spain announced it won't admit unvaccinated British visitors starting December 1.
Italy was going through lists of airline passengers who arrived in the past two weeks after a business traveller who returned from Mozambique and landed in Rome on November 11 tested positive for Omicron. The Lazio region's top health official, Alessio D'Amato, said that "controls at airports, ports and train stations have been reinforced".
French Health Minister Olivier Veran said that, while his country had no confirmed cases yet, "it is probable that there currently are cases in circulation".
While it is not clear yet how existing vaccines work against the Omicron variant, Veran said France isn't changing its strategy to fight the latest surge of infections driven by the Delta variant that centres on increasing vaccinations and boosters.
David Hui, a respiratory medicine expert and government adviser on the pandemic in Hong Kong, agreed with that strategy.
He said the two people who tested positive for the Omicron variant had received the Pfizer vaccine and exhibited very mild symptoms, such as a sore throat.
"Vaccines should work but there would be some reduction in effectiveness." - AP