At least 17 people suspected of having the Omicron variant of coronavirus after a 'super spreader' Christmas party in Oslo were fully vaccinated, city health officials have said.
On Friday, it was confirmed 13 people in Norway had tested positive for the variant in the wake of a corporate Christmas party in Oslo last week.
A city health official told the AFP news agency that 60 people of the 100-plus guests had tested positive.
"Health authorities have confirmed a further 12 cases of Omicron in Oslo after an outbreak," the city of Oslo said in a statement.
"So far 13 Omicron cases have been confirmed after sequencing. More cases are expected."
Officials have warned the number of Omicron-confirmed cases could increase.
“All of them had been vaccinated, none of them had symptoms and they had all done self-tests” before attending the dinner," Tine Ravlo told AFP.
He added that most of those infected had mild symptoms and that the party organisers had broken no rules.
The Omicron outbreak at the party was the biggest outside of South Africa, with more than 60 people possibly infected, officials have said.
Preben Aavitsland, a senior physician at the Norwegian Institute of Public Health, said: "This party has been a super spreader event.
"Our working hypothesis is that at least half of the 120 participants were infected with the Omicron variant during the party.
“This makes this, for now, the largest Omicron outbreak outside South Africa."
Norway has responded swiftly to the outbreak, reintroducing some social distancing measures and encouraging people to work from home.
From Friday, anyone arriving in Norway, whether vaccinated or unvaccinated, must take a COVID test within 24 hours of arrival.
In areas with high infection rates such as Oslo, the use of face masks in crowded places is mandatory, as is working from home for those who are able to.
Some 88% of adults in Norway, and 71% of all Norwegians, are fully vaccinated. About 11% have received a booster shot.
Austria was plunged into lockdown in November in response to the fourth wave of COVID sweeping Europe. It became the first country to announce mandatory vaccines from next year. On Friday Switzerland announced that venues could refuse entry to unvaccinated people. Germany has also announced measures that place major restrictions on unvaccinated people or those who have recently recovered from infection, including being banned from restaurants, cinemas and many shops.
European Commission president Ursula von der Leyen had suggested on Wednesday that the entire European Union should consider mandatory COVID vaccinations in response to the spread of the “highly contagious” Omicron variant.
In England, the government has reintroduced the mandatory wearing of masks in shops and on public transport, but has stopped short of further restrictions.
The Prime Minister said that Christmas 2021 would be "considerably better than the last" during a press conference on Tuesday.
He added: “We’ve got the measures in place to fight Delta, which we think are appropriate, and then we’re bringing in some tougher measures to stop the rapid seeding of Omicron in this country to give us the time we need to get the boosters in and of course to find out more.”
The European Centre for Disease Prevention and Control has said there may be a chance current vaccines will be less effective against the variant.
It said there is a,lso an increased chance of reinfection but they did say that "the full extent to which the Omicron VOC evades or erodes existing vaccine- or infection-derived immunity remains uncertain".
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