LONDON (NewsNation Now) — A coronavirus variant in the United Kingdom has caused alarm because of the possibility that it might spread more easily.

British Prime Minister Boris Johnson has said a variant of the coronavirus, which could be up to 70% more transmissible, is spreading rapidly in Britain. A separate variant, first found in South Africa, is also raising concern.

The World Health Organization has said that there is not enough information to determine whether the new variants could undermine vaccines being rolled out internationally.

Dr. Anthony Fauci, the top U.S. infectious disease expert, said data coming from Britain indicates the vaccines still will block the virus. But the U.S. also will do tests to be sure. The first detected case of the variant in the U.S. was announced Tuesday afternoon, in a male in his 20s in Colorado with no travel history.

Moncef Slaoui, the chief science adviser for the U.S. government’s COVID-19 vaccine push, also quelled concerns about the vaccine rollouts.

“My expectation is, this will not be a problem,” Slaoui said.

The following countries are among those that have reported variants of the novel coronavirus, first identified in China a year ago, among their populations.

UNITED STATES

COLORADO: Tuesday afternoon, Colorado Governor Jared Polis announced they discovered Colorado’s first case of the COVID-19 variant B.1.1.7. Officials say the case was found in an individual in his 20s with no recent travel history; the male is currently in isolation in Elbert County.

CALIFORNIA: Wednesday, California Governor Gavin Newsom confirmed a case of the coronavirus variant was detected in Southern California.

SWITZERLAND

Switzerland has documented five cases of the variant from Britain and two cases of the South African mutation, a health ministry official said on Tuesday, adding he anticipates more cases will emerge.

DENMARK

Denmark has identified 33 infections with the variant spreading in Britain, authorities said on Dec. 24.

FRANCE

France, with the highest number of coronavirus cases in the European Union, recorded its first case of a variant in a Frenchman arriving back from London.

INDIA

India has found six cases of a variant of the coronavirus on a flight from Britain and will likely extend a flight ban to guard against it, officials said on Tuesday.

JAPAN

Japan on Monday detected the variant found in South Africa, the government said, the first such discovery in a nation that has already identified more than a dozen cases of the variant spreading in Britain.

SOUTH KOREA

South Korea said the variant found in Britain was found in three people who had entered South Korea from London on Dec. 22. Officials vowed to speed up vaccinations.

NORWAY

Norway said the variant circulating in Britain had been detected in two people who arrived from the United Kingdom earlier in December.

AUSTRALIA

Australia said two travelers from the United Kingdom were carrying the variant found in Britain.

JORDAN

Jordan has detected its first two cases of the variant spreading in Britain. The kingdom last week banned flights to and from Britain until Jan. 3.

GERMANY

Germany said the variant from Britain had been found in a passenger flying to Frankfurt from London on Dec. 20. It seems to have been present in Germany since November, the Die Welt daily reported on Monday.

ITALY

Italy detected a patient infected with the variant found in Britain, the health ministry said on Dec. 20.

PORTUGAL

The variant linked to Britain has been detected on the island of Madeira in PORTUGAL, the regional civil protection authority said.

FINLAND

Health officials in Finland said the variant circulating in Britain has been detected in two people, while the variant spreading in South Africa has been detected in one other person.

SWEDEN

Sweden said the variant circulating in Britain had been detected after a traveler from Britain fell ill on arrival and tested positive.

CANADA

Officials in Canada said that two confirmed cases of the variant detected in the United Kingdom had appeared in the Canadian province of Ontario.

IRELAND

Ireland on Christmas Day confirmed the presence of the British variant and said further testing would establish how far it has spread.

LEBANON

Lebanon detected its first case of a variant of the coronavirus on a flight arriving from London.

UNITED ARAB EMIRATES

United Arab Emirates discovered a “limited number” of cases of people infected with a new variant, a government official said on Tuesday. He said those affected had travelled from abroad, without specifying from where or the number of cases.

SINGAPORE

Singapore confirmed its first case of the variant found in Britain, the patient arriving from Britain on Dec. 6, while 11 others who were already in quarantine had returned preliminarily positive results for the new strain.

ISRAEL

Israel detected four cases of the coronavirus emerging in Britain. Three of the cases were returnees from England.

HONG KONG

The variant spreading in Britain appears to have infected two students who returned to Hong Kong from the U.K., the Department of Health said last week.

PAKISTAN

Pakistan health officials said on Tuesday the variant found in Britain had been detected in the southern province of Sindh.

NIGERIA

Another variant of the coronavirus may have emerged in Nigeria, the head of Africa’s disease control body said, cautioning that more investigation was needed.

The Associated Press and Reuters contributed to this report. All reporting by Nick Macfie of Reuters, and AP staff.