(Bloomberg) -- Oslo is heading back to working from home and using face masks after an outbreak at a Christmas party raised the prospect of a jump in omicron variant infections.

Home office will now be required for part of the week in Norway’s capital and 21 other municipalities, while face masks must be worn in shops, public transport, bars and restaurants, Health and Care Services Minister Ingvild Kjerkol told reporters on Thursday. Bars will have to serve customers at tables, guests will need to register to receive notices of infection exposure and limits will be placed on events held inside. 

The restrictions come after a case of omicron was detected and more are feared among more than 50 people that tested positive in an outbreak in Oslo. The Nordic nation, which has been among the best to weather Covid-19 over the past year in Bloomberg’s Covid Resilience Ranking, has declined to 11th spot this month.

Working from home, the use of face masks and limiting the number of contacts for adults are now recommended nationwide. 

The cases of new variant were detected after a Christmas party held by renewable power producer Scatec ASA, E24 reported, citing infection control physician Tine Ravlo. The Norwegian Institute of Public Health is now examining samples to determine how many are a result of the new variant, it said. All the participants were recommended to test before attending and had a high vaccination coverage.

Scatec, which operates in more than 15 countries, including South Africa, had 120 employees at the event on Nov. 26, a spokesman for the company said. The impact of the infections on the company’s operations are expected to be limited, he said, referring all health related questions to authorities.

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