New Omicron offshoot BA.2 is over 1.5 times more contagious than the original, early data from Denmark suggests

• An emerging subtype of Omicron is spreading 1.5 times quicker than the original, Denmark estimates.
• Scientists are closely monitoring BA.2 since it edged out BA.1 in Denmark in recent weeks.

An offshoot of Omicron, BA.2, is spreading over 1.5 times more quickly than the original BA.1, Denmark's leading public health institute said Wednesday.

"Preliminary calculations indicate that BA.2 is effectively well over one and a half times more contagious than BA.1," the Statens Serum Institute (SSI) said in a statement.

An expert from the SSI told Insider that the subvariant was spreading fastest among children 5 to 17 years old.

There is no evidence that it is causing more severe disease, Danish Health Minister Magnus Heunicke said at a press conference supporting the findings, per Reuters.

Denmark was one of the first countries where Omicron initially spread, meaning its data may give a picture of how other outbreaks could pan out.

BA.2 became dominant in Denmark in the second week of January, but is yet to spread widely across the world. For now, BA.1 is still the subtype of Omicron responsible for 98% of infections worldwide, per the SSI.

The institute said that if its assessments of BA.2's infectiousness are correct, then the current outbreak in Denmark could extend into February, longer than previously expected.

BA.2 is a subtype of the coronavirus, called a lineage, that falls under the broader Omicron category.

Omicron BA.2 has been emerging since late December. It quickly became dominant in Denmark and is spreading in the UK, Singapore, India, and the Phillippines — edging out BA.1, the original lineage of Omicron.

BA.2 has been found in at least 40 countries, including the US, CBS News reported.

So far, it seems BA.2 is spreading more quickly in Denmark than in other countries, the SSI said.

In an interview Thursday, Dr. Camilla Holten Møller, the head of the SSI's expert group for COVID-19 modeling told Insider that the SSI data is based on crude case rates which could turn out to be different in other countries.

"This doesn't really say anything about why BA.2 has a growth advantage," Møller said.

"I think there are some signals now from Sweden and Norway, pointing towards the same development. India and the Philippines reported quite a large proportion of B.2, but it hasn't really at all occurred in South Africa," she said.

She also noted that in Denmark BA.2 was spreading most quickly among children. That's likely because of "high activity with schools fully open" and because that age group is the least vaccinated in Denmark, she said.

Omicron is characterized by an inordinate amount of mutations compared to previous variants.

Although BA.1 and BA.2 share a lot of these mutations, BA.2 also has about 50 mutations BA.1 doesn't, as Insider's Catherine Schuster-Bruce previously reported.

Scientists are working to figure out whether these mutations affect BA.2's ability to evade existing immunity, make it more infectious, or reinfect people who had BA.1, the SSI said.

The news came as Denmark, the UK, Ireland, and the Netherlands started lifting most COVID-19 restrictions.