The first-known case in Wales was discovered on Friday, and Northern Ireland has said it expects to discover an instance of the variant in a matter of days.
How did omicron reach the UK?
According to health secretary Sajid Javid, the two cases initially found in England – in Brentwood, Essex, and in Nottingham – were “linked” and were traced to southern Africa.
While targeted sequence testing of other cases was launched in those areas, Mr Javid admitted that air passengers from South Africa who arrived in the UK last Friday were not tested, despite fears they could be carrying the omicron variant.
The travellers left airports in normal ways – including on public transport – and were only then asked to take Covid tests and to go into isolation if they tested positive, the health secretary said.
It means the UK does not know how many arrivals from South Africa were infected – after a staggering 10 per cent of people on one flight into the Netherlands tested positive for the omicron variant.
Where else are omicron cases being detected?
New infections linked to the omicron variant have been confirmed in at least 38 countries, including Belgium, Canada, Australia, the Netherlands, Denmark, Germany, Israel, Italy, the Czech Republic and Hong Kong.
How transmissible and dangerous is omicron?
Urging countries on Friday not to panic, but rather to prepare for the likely spread of omicron worldwide, the World Health Organisation (WHO) said it would likely take another fortnight to establish how transmissible and dangerous the variant is.
While scientists believe it may be considerably more infectious than the delta variant, the UN health agency stressed that the data is still only preliminary.
The variant’s 32 mutations include E484A, K417N and N440K, which are associated with helping the virus to escape detection from antibodies.
Another mutation, N501Y, appears to increase the ability of the virus to gain entry to our cells, making it more transmissible.
In South Africa, where approximately 42 vaccine doses have been administered per 100 people, the WHO said there had been a 311 per cent surge in coronavirus cases in the last seven days of November, compared to the previous week.
South Africa is seeing more cases of re-infection than with previous variants, the health agency said, citing a microbiologist from the country’s National Institute for Communicable Diseases.
But despite cases of the new variant emerging in dozens of countries around the world, not a single death has yet been attributed to it, the WHO said.
Of the 150 cases identified in the UK, none are reported to have been hospitalised, although the UK Health Security Agency noted that the infections are recent and there tends to be “a lag between onset of infection and hospitalisation and death”.
“We need to be prepared and cautious, not panic, because we’re in a different situation to a year ago,” top WHO scientist Soumya Swaminathan said, suggesting that omicron could become the globally dominant variant, in the same way that delta now accounts for 99 per cent of cases.
Is omicron resistant to vaccines?
The spike proteins coating the Covid virus allow it to attach and gain entry to human cells. Vaccines train the body to recognise these spikes and neutralise them.
The 32 mutations in the omicron variant’s spike protein will change the shape of this defence structure and make the spike protein less recognisable to antibodies.
Antibodies then won’t be as strong in attacking the virus, which would then be able to slip past immune defences and cause infection.
However, WHO emergencies director Michael Ryan said on Friday that there was no evidence to back changing existing vaccines to tailor them to the new omicron variant, suggesting that the focus should be on distributing jabs more widely.
What are scientists saying about omicron?
Scientists have mixed opinions over whether or not we should be worried about the latest variant.
Dr Tom Peacock, a virologist at Imperial College London, warned that the variant could be “of real concern” due to its 32 mutations.
He wrote on Twitter that the variant “very, very much should be monitored due to that horrific spike profile” which could mean that it is more contagious than any other variant so far.
Meanwhile, Prof Balloux of UCL said that at the moment there is “no reason to get overly concerned”, and also said that “it is difficult to predict how transmissible it may be at this stage.”
Professor Andrew Pollard, of the Oxford Vaccine Group, said it is “extremely unlikely” to trigger a new wave in the pandemic in the UK.
Professor Calum Semple, who sits on the Sage advisory group, said: “The headlines from some of my colleagues saying ‘this is horrendous’ I think are hugely overstating the situation.
“Immunity from the vaccination is still likely to protect you from severe disease,” he said.
“You might get a snuffle or a headache or a filthy cold but your chance of coming into hospital or intensive care or sadly dying are greatly diminished by the vaccine and still will be going into the future.”
Dr Meera Chand, the Covid-19 incident director at the UK Health Security Agency, said that the status of new Covid variants worldwide is constantly being monitored at random and that a small number of cases with “new sets of mutations” were “not unusual.”
She explained: “As it is in the nature of viruses to mutate often and at random, it is not unusual for small numbers of cases to arise featuring new sets of mutations. Any variants showing evidence of spread are rapidly assessed.”
What is the UK doing to curb the spread?
Boris Johnson announced on Saturday evening that people will be ordered to wear masks in shops and on public transport in England from 30 November in response to the omicron variant.
The prime minister also said that contacts of omicron cases must isolate for 10 days. All international arrivals must also take a day 2 PCR test and isolate until they receive a negative result.
Mr Johnson told the press conference that the rules will be reviewed before Christmas in three weeks’ time.
Meanwhile, southern African nations have also been added to the UK’s red list for international travel.
South Africa’s health minister, Joe Phaahla, said travel restrictions placed on his country were “uncalled for”.
He claimed they would not prevent the virus’ spread and suggested regular testing and mask-wearing to prevent surges of infections.
Which countries are closing their borders?
While the WHO has repeatedly warned against implementing blanket travel bans except in nations whose health systems are unable to withstand a surge in infections, Japan, Morocco, and Israel have decided to shut their borders to all overseas citizens.
A number of nations, including the UK, US and some in the European Union, have placed restrictions on travel from nations in southern Africa.
The UK has added Botswana, Angola, Eswatini, Namibia, Lesotho, South Africa, Mozambique, Malawi, Zambia and Zimbabwe to its travel red list.
Australia announced a two-week delay to its plans to reopen borders to skilled migrants and students from 1 December.
In response to the various travel bans, the president of South Africa Cyril Ramaphosa urged nations to “urgently reverse” these decisions as they could spook economies.
The emergence of omicron is a wake-up call for the world to realise the impact of “vaccine inequality”, Mr Ramaphosa said, warning that further variants are inevitable until everyone is vaccinated.