Basically as of now, the experts only knows the new strains spread more easily, but don't know if it's more deadly, and unclear whether they pose any concern for vaccines or cause more severe disease.

When China first found out there's a new coronavirus, they also know very little about it. As I said before, their biggest mistake was to assume it's SARS like, more deadly but also more limited human to human transmission relative to Covid-19.

London Begins Emergency Lockdown as U.K. Fights New Virus Strain

• Capital, southeast England move into new tier; trains jammed
• New mutation forces Johnson to scrap five-day Christmas easing

More than 16 million Britons are now required to stay at home as a lockdown came into force Sunday in London and southeast England, part of Boris Johnson’s attempt to control a fast-spreading new strain of the coronavirus.

The measures ban household mixing in the capital and the southeast, and restrict socializing to just Christmas Day across the rest of England. Residents across the country were told to keep to their local areas.

Johnson had originally planned to ease pandemic rules for five days during the holiday, but made an abrupt change of tack after emergency talks on the virus mutation with his top officials. Emerging scientific evidence suggests the new variant -- which currently appears virtually unique to the U.K. -- can spread significantly more quickly than previous strains in circulation and is behind a huge surge in infections in recent days.

“When the virus changes its method of attack we must change our method of defense,” 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.”

U.K. Says Virus Strain Afflicting London Spreads More Easily

Major Blow

Covid-19 case rates nearly doubled in London over the past week, with almost 60% of these infections attributed to the new strain, according to government officials.

In response, Johnson announced a new top tier of pandemic curbs for hot-spot regions around the capital. All non-essential shops will close and 16.4 million people -- 31% of England’s population -- were ordered to stay at home.

The measures will be a major blow to retail businesses at what is usually their busiest time of year. The U.K. has already suffered its deepest recession since the Great Frost of 1709 and ministers have been forced to extend crisis loans and wage support programs amid fears that unemployment will rocket.

The toughest Tier 3 measures in the county of Kent have failed to stop the spread, prompting Johnson to introduce a new top level of infection controls, Tier 4.

Tier 4 Lockdown Rules from Dec. 20

• People must stay at home, unless they must travel for work, education, health care
• Households are largely banned from mixing, there will be no Christmas bubbles
• All non-essential shops, indoor leisure and entertainment, and personal care such as hair salons will close
• Socializing limited -- one person can meet one other from a different household, in a public space outside. Exceptions apply for support bubbles
• People will be advised not to enter Tier 4 areas and residents in Tier 4 areas must not stay overnight away from home
• Foreign travel should be avoided for all but essential trips
• Tier 4 applies to: whole of London, Kent, Buckinghamshire, Berkshire, most of Surrey, Bedfordshire, Luton, Hertfordshire, most of Essex
• Rules apply for two weeks, will be reviewed on Dec. 30

Reaction to Johnson’s change in plan was swift -- last week, he dismissed calls from Labour leader Keir Starmer for tighter restrictions and urged Britons to have a “merry little Christmas.” At least two Sunday newspapers published front pages noting, “Christmas is cancelled,” with pictures of a downbeat Johnson. Images showed hundreds of people at St. Pancras station waiting for trains to take them north and out of the capital.

England’s Chief Medical Officer Chris Whitty said that the new variant was faster spreading, and likely behind the alarming climb of case numbers around the capital and southeast of the country.

“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,” Whitty said. “Given this latest development it is now more vital than ever that the public continue to take action in their area to reduce transmission.”

Britain joined Italy and Austria in tightening curbs during the holiday season, with all three countries facing rapidly rising case numbers.

Rising Rate

London's virus infection rate is rising sharply

The situation has deteriorated dramatically across Europe, just as vaccines are being rolled out. French President Emmanuel Macron contracted the illness and countries like Italy and Germany introduced new measures during the festive period.

Unpredictable Mutations

Viruses tend to evolve or mutate quickly, particularly those like flu that require new vaccines to be developed each year because of changes in key proteins. SARS-CoV-2 also changes, although generally at a slower pace than some other viruses because it has a self-correcting mechanism that keeps its genetic sequence relatively stable.

Other variants in the coronavirus have been reported in the past, including one in minks, which are susceptible to the virus. That was feared to be highly transmissible and was reported to the World Health Organization. Millions of farmed mink were culled, although as of Nov. 20 the WHO said the most worrying strain linked to the animals is no longer circulating in humans.

In other developments:

• The government warned people they must not break the rules on gatherings on New Year’s Eve
• London’s Metropolitan Police said officers will crack down on groups flouting the law and patrols will focus on the busiest areas
• In Scotland, First Minister Nicola Sturgeon announced travel restrictions with England and a new lockdown from Dec. 26, including the closing of all hospitality and non-essential stores.
• Schoolchildren in Scotland will return in January in phases, Sturgeon said
• A group of lockdown skeptics in Johnson’s Conservative Party demanded he recall Parliament so elected representatives could vote on whether to approve or reject the new measures.

Now there was a mass exodus, people trying to leave London before lock down.