British Prime Minister Boris Johnson said that the UK must take "targeted and proportionate measures now" amid concerns over the new Omicron Covid-19 variant.
"I must stress this: As always, with a new variant, there are many things we just cannot know at this early stage. Our scientists are learning more hour by hour. It does appear that Omicron spreads very rapidly and can be spread between people who are double vaccinated. There is also a very extensive mutation, which means it diverges quite significantly from previous configurations of the virus, and as a result, it might at least in part reduce the protection of our vaccines over time," Johnson said in a press conference.
Two cases of the variant have been detected in the UK so far.
Johnson also announced additional measures:
"We're not going to stop people traveling. But we will require anyone who enters the UK to take a PCR test by the end of the second day after their arrival and to self-isolate until they have a negative result," Johnson said. "...In addition to the measures we're already taking to locate those who have been in countries of concern over the last 10 days, we will require all contacts of those who test positive with a suspected case of Omicron to self-isolate for 10 days regardless of your vaccination status."
The prime minister said his country will also "boost the booster campaign" in an effort to get as many people possible their vaccine booster shot.
“We don't yet exactly know how effective our vaccines will be against Omicron, but we have good reasons for believing they will provide at least some measure of protection. And if you're boosted, your response is likely to be stronger. So it's more vital than ever that people get their jabs and we get those boosters into arms as fast as possible,” Johnson said.
Johnson said rules on face coverings in stores and on public transportation will be "tightening up."
The new measures will be reviewed in three weeks, he said.
Johnson expressed his "deep gratitude" to scientists in South Africa for identifying this variant.
Watch Boris Johnson's speech: