London, England is going into an emergency lockdown as a wave of COVID-19 infections brought on from a new fast-spreading strain has been found in the city.

London, COVID-19“When the virus changes its method of attack we must change our method of defense,” Prime Minister Boris Johnson said at a news conference Saturday. “Without action, the evidence suggests infections would soar, hospitals would become overwhelmed and many thousands more would lose their lives.”

The new policy is a stark change of plans for the city, which had previously planned to ease restrictions as we near the holidays. 

Bloomberg reports that the strain is currently unique to the United Kingdom. Sixty-percent of new cases in London in the last week were a result of the new strain.

“There is no current evidence to suggest the new strain causes a higher mortality rate or that it affects vaccines and treatments, although urgent work is underway to confirm this,” said England’s Chief Medical Officer Chris Whitty. “Given this latest development, it is now more vital than ever that the public continue to take action in their area to reduce transmission.”

The new restrictions include a stay-at-home order, the closure of all non-essential shops, indoor leisure and entertainment, and more. The rules will be revisited on Dec. 30th.