Meanwhile in the UK...
A SAGE adviser today hinted a third national lockdown including mass school closures may be required to suppress Covid as he insisted 'keeping people apart' stops the virus from spreading.
Professor Sir Mark Walport claimed the 'mutant' strain of coronavirus was transmitting rapidly among children, with those aged between 12 and 16 seven times more likely to 'infect' a household.
Speaking on the BBC's Andrew Marr Show as Liverpool's leaders called for a blanket shutdown, he said it would be 'very, very difficult' to keep the disease under control 'without tighter social distancing measures'.
Sir Mark also suggested the UK has struggled to keep cases down because it is a 'western liberal democracy', hinting that draconian countermeasures adopted in unfree countries like Vietnam had suppressed the virus.
Asked if Tier 4 restrictions were enough, the former Chief Scientific Adviser today said: 'It's the Tier 4 restrictions, it's obeying them.
'It is thinking about breaking essentially every possible route of transmission we possibly can. Those are the things that are absolutely necessary and it is pretty clear we're going to need more.'
Talking about 'mutant' Covid, he said: 'We now have a much more transmissible variant and I'm afraid this is the natural evolution of viruses.
'The ones that can transmit most effectively have an advantage over other variants and so it is clear this variant is transmitting more readily. It's transmitting more readily in younger age groups as well.
'It's good to note it doesn't appear to cause worse disease or that it is going to be more resistant to the effects of the vaccine, but it is going to be very, very difficult to keep it under control without tighter social distancing measures.'
Sir Mark continued: 'The thing that actually stops the virus, and we know that it can do, is keeping people apart. The virus can only get from one person to another through proximity, and so it really is about doing everything we possibly can to keep ourselves as safe as possible.'
It comes as Boris Johnson today refused to rule out a total shutdown, telling Marr he is 'reconciled' to imposing further restrictions on public life as the number of coronavirus cases rises.