Omicron is expanding, reaching the United States from the United States to South Korea

Most infections come from traveling across the border.

The omicron variant of Covid-19, first identified in South Africa, has now been detected in countries from the US to South Korea, highlighting the difficulties in reducing new contagious strains.

Most infections come from traveling across the border. Israel, for example, said a confirmed case from Malawi went by bus from Tel Aviv. The first case in Italy traveled across the country for days before testing positive. The first case of omicron was confirmed in the United States to a person who returned from South Africa, the Centers for Disease Control and Prevention said.

Researchers around the world are wondering how to fully understand the impact of the new strain, and governments have banned travelers from South Africa and neighboring countries because omicron could evade vaccine protection and fuel new waves.

Here’s how far omicron has come:

South Africa: Early PCR tests showed that 90% of the 1,100 new cases reported in the middle of the week in the province that includes Johannesburg were caused by the variant. The daily number of new confirmed cases has almost doubled to 8,561 infections, according to the National Institute of Communicable Diseases.

Botswana: At least 19 cases detected

UK: Five cases, the most recent two cases are unrelated and unrelated to the previous three confirmed travel-related infections in South Africa.

Germany: Two cases of passengers arriving at Munich’s South African airport, AFP reported, citing regional officials.

Netherlands: 13 cases detected among travelers from South Africa

Denmark: Two cases on arrival from South Africa

Belgium: A case

Israel: One case confirmed and others suspected, starting with November 27.

Italy: A case that moved around the country before being tested positive

Czech Republic: One case, according to local media

Austria: A confirmed case in Tyrol for a person arriving from South Africa. Authorities are examining another 30 suspicious cases

Switzerland: Three cases. People are isolated

France: Thirteen suspicious cases, according to a government spokesman

Portugal: Preliminary tests in 13 cases suggest “strongly” that they are all related to the omicron variant. One of the cases involves a person who has recently had a trip to South Africa.

Spain: A case, according to the Ministry of Health in Madrid

Sweden: One case, according to the country’s Public Health Agency

Hong Kong SAR: Four confirmed imported cases, two related to South Africa and the other to Nigeria

Australia: Six cases in New South Wales. The sixth case was a fully vaccinated traveler who recently visited South Africa, according to NSW Health.

Japan: A confirmed patient who returned from Namibia. A second case was reported to a person who arrived from Peru

Canada: Five cases, including a first case in Quebec, that traveled from Nigeria, according to Reuters, citing Ottawa Public Health

Brazil: Two cases. Found in samples from a newly married couple from South Africa

Norway: Two confirmed cases in Oygarden. Both had traveled to South Africa

Ireland: A confirmed case of a person who has traveled to a risk area

US: A case detected in California of a traveler who returned from South Africa and was completely vaccinated, according to the CDC

South Korea: Five cases have been confirmed, including a couple returning from Nigeria and their contacts

United Arab Emirates: A confirmed case

Saudi Arabia: A confirmed case