Israel is the first country to ban the entry of all foreign travellers in a bid to contain the new Omicron Covid variant.
Scientists fear the strain, which first emerged in South Africa, is more likely to evade antibodies and has a higher rate of re-infection.
The UK, US, EU and Australia are among a host of nations that have imposed restrictions on southern African countries in response to warnings over its transmissibility.
But Israel has gone one step further by shutting its borders completely.
The country’s government will also reintroduce counter-terrorism phone-tracking technology for contact testing in order to contain the spread of the new strain.
Prime Minister Naftali Bennett said in a statement that the ban, pending government approval, would last 14 days.
Israel has so far confirmed one case of the variant and seven other suspected cases.
Earlier, two cases were confirmed in the UK – in Brentwood and Nottingham.
The cases are believed to be linked to each other and to travel in South Africa, and both people, along with their households, are self-isolating.
At a Downing Street press conference earlier today, Boris Johnson said face masks will be mandatory in shops and on public transport from next week, contacts of Omicron Covid cases must self-isolate, and international arrivals will have to quarantine until they test negative.
He said the measures were necessary to ‘buy time for our scientists to understand exactly what we’re dealing with’.
Although he refused to rule out a lockdown, he insisted this Christmas would be better than last year’s – when people across the country were plunged into tier four restrictions.
While the effectiveness of vaccines against the variant is currently unclear, Mr Johnson said there are ‘good reasons for believing they will provide at least some measure of protection’.
He said: ‘We continue to be in a strong position largely thanks to the speed of the vaccine rollout, another booster rollout and I think I’m going to stick with the formula I’ve used before, which is I’m pretty confident to absolutely confident this Christmas will be considerably better than last Christmas.’
The new rules come after the UK placed 10 countries in the southern African region on its red travel list.
The Prime Minister said the new measures were ‘temporary and precautionary’ and will be reviewed in three weeks.
In the mean time, the government’s vaccine experts will be tasked with considering whether to extend booster jabs to all over-18s.
The UK is the second European nation to have reported the presence of Omicron after Belgium said it had identified a single case on Friday.
On Saturday night, cases were also confirmed in Germany and Italy.
There was also concern in the Netherlands after 61 people tested positive for Covid-19 after arriving on two flights from South Africa on Friday. Tests are now underway to determine if this is Omicron.
The World Health Organisation yesterday classed it as a variant of concern because of its high number of mutations and early evidence that suggests it carries a higher degree of infection than other variants.
That means people who contracted Covid-19 and recovered could catch it again.
It could take weeks to know if current vaccines are less effective.
With so much uncertainty about Omicron, countries around the world have been taking a safety-first approach in the knowledge that previous outbreaks of the pandemic have been partly fuelled by lax border policies.
But South Africa has complained it is being punished rather than applauded for reporting the strain.
The variant’s swift spread among young people in South Africa has alarmed health professionals, even though there was no immediate indication whether the variant causes more severe disease.
In just two weeks, Omicron has turned a period of low transmission in the country into one of rapid growth.
A number of pharmaceutical firms, including AstraZeneca, Moderna, Novavax and Pfizer, said they have plans in place to adapt their vaccines in light of the emergence of Omicron.
Professor Andrew Pollard, director of the Oxford Vaccine Group which developed the AstraZeneca vaccine, expressed cautious optimism that existing vaccines could be effective at preventing serious disease from the variant.
He said most of the mutations appear to be in similar regions as those in other variants.
‘That tells you that despite those mutations existing in other variants the vaccines have continued to prevent serious disease as we’ve moved through Alpha, Beta, Gamma and Delta,’ he told BBC radio.
‘At least from a speculative point of view we have some optimism that the vaccine should still work against a new variant for serious disease but really we need to wait several weeks to have that confirmed.”
‘It’s extremely unlikely that a reboot of a pandemic in a vaccinated population like we saw last year is going to happen.’
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