The heavily mutated new coronavirus variant was in Europe several days earlier than previously known, health officials said Tuesday.
And the number of countries where it has been found increased to at least 20, raising questions about whether the pandemic is about to surge once again.
The Netherlands’ National Institute for Public Health and the Environment said that samples taken on Nov. 19 and Nov. 23 — before the Nov. 24 announcement of omicron’s existence — tested positive for the variant.
Health officials have notified the two infected people and are doing contact tracing to try to limit the spread.
Mutations in the omicron variant strongly suggest that it is more contagious than previous forms of the virus, scientists say.
They caution that they cannot be sure without more testing and data, but the evidence so far is sobering.
On Tuesday, the Biden administration was looking at ways to toughen coronavirus screening for people flying to the United States, including whether to require all passengers to provide a negative result from a test taken within 24 hours of departure.
The concern is that the current rules, which allow fully vaccinated people to take a test up to three days before departing on a flight to the United States, might not be stringent enough.
New coronavirus cases have rocketed from about 300 a day in mid-November :
On Tuesday, the Biden administration was looking at ways to toughen coronavirus screening for people flying to the United States, including whether to require all passengers to provide a negative result from a test taken within 24 hours of departure.
The concern is that the current rules, which allow fully vaccinated people to take a test up to three days before departing on a flight to the United States, might not be stringent enough.
A day after warning that the risk from omicron was “very high,” the World Health Organization on Tuesday said that unvaccinated people who are over age 60, are sick or have underlying health risks “should be advised to postpone travel.”
In Greece, the prime minister announced that COVID vaccinations would be obligatory for people age 60 and older, and that those who failed to book a first shot by Jan. 16 would face fines.
In South Africa, where the variant was first announced and is already widespread, reported new coronavirus cases have rocketed from about 300 a day in mid-November to about 3,000 a day, the fastest rate of increase in the world.
On two flights from South Africa to the Netherlands on Friday, just as a cascade of bans on travel from southern Africa were being announced, 61 passengers tested positive for the virus, at least 14 of them for omicron.