The UK on Thursday expressed alarm over the newly discovered coronavirus variant spreading in South Africa.
The UK Health Security Agency said the B.1.1.529 variant contains a spike protein that differs dramatically from the one in the original coronavirus that COVID-19 vaccines are based on.
"This is the most significant variant we have encountered to date and urgent research is underway to learn more about its transmissibility, severity, and vaccine-susceptibility," UKHSA Chief Executive Jenny Harries said.
British Health Secretary Sajid Javid suggested it may impact the effectiveness of vaccines.
"What we do know is there's a significant number of mutations, perhaps double the number of mutations that we have seen in the Delta variant," Health Secretary Sajid Javid told broadcasters.
"And that would suggest that it may well be more transmissible and the current vaccines that we have may well be less effective."
Britain earlier rushed to introduce travel restrictions on South Africa and five neighboring countries, including Namibia, Botswana, Zimbabwe, Lesotho, and Eswatini.
A World Health Organization working group will meet on Friday to assess the variant and possibly assign it a name from the Greek alphabet.