The Omicron Covid-19 variant has been designated a “variant of concern” by the World Health Organisation and Boris Johnson has announced a set of emergency measures to tackle it here in the UK.
From Tuesday, face masks will be mandatory again in shops and on public transport in England, bringing the country in line with existing policies elsewhere in the UK. Secondary school teachers and pupils will also be advised to wear masks in communal spaces.
The rules on self-isolation are also changing; anyone who’s identified as a contact of an Omicron case will have to isolate for 10 days, regardless of vaccination status, and anyone returning to the UK from aboard will have to isolate until they have a negative PCR test.
The policy changes mark the biggest shift in Covid rules we’ve seen in the UK for months, so what’s behind the somewhat sudden announcements? Here’s what we know (and don’t know) about the Omicron variant so far.
Omicron has been detected in a number of countries
The variant, also called B.1.1.529, was first detected in Botswana and soon spread across other countries in southern Africa.
It’s since been detected in Canada and Hong Kong and has been identified widely across Europe, in countries including Denmark, the Netherlands, Germany, the Czech Republic, Italy, Portugal and Belgium.
In the UK, we know there have been at least three cases in England, while six further cases have been identified in Scotland as of Monday November 29.
It’s the most heavily mutated variant yet
Professor Lawrence Young, a virologist and professor of molecular oncology at Warwick Medical School, said the Omicron variant is “very worrying” because it is “the most heavily mutated version of the virus we have seen to date”.
“This variant carries some changes we’ve seen previously in other variants but never all together in one virus. It also has novel mutations that we’ve not seen before,” Prof. Young explained.
“Some of the mutations that are similar to changes we’ve seen in other variants of concern are associated with enhanced transmissibility and with partial resistance to immunity induced by vaccination or natural infection.”
Scientists have now found 50 mutations in Omicron, 30 of which are on the spike protein. During Saturday’s Downing Street briefing, chief medical officer Professor Chris Whitty explained why this is significant.
“There are quite extensive mutations on the spike protein which is an important part of the virus. The reason that is important is because that is the bit all the vaccines are against and indeed which most natural immunity is against,” he said. “There is a reasonable chance that at least there will be some degree of vaccine escape with this variant.”
Professor Whitty said there’s a chance this variant is more transmissible and that it could be more readily spread among people who are double vaccinated than previous variants – but it’s too early to say what implications that will have.
We do not know if it will cause more severe disease
It is not yet clear whether infection with Omicron causes more severe disease compared to infections with other variants, including Delta, the World Health Organisation has said.
“Preliminary data suggests that there are increasing rates of hospitalisation in South Africa, but this may be due to increasing overall numbers of people becoming infected, rather than a result of specific infection with Omicron,” the WHO said in a statement on Sunday November 28.
“Initial reported infections were among university students—younger individuals who tend to have more mild disease – but understanding the level of severity of the Omicron variant will take days to several weeks.”
In the US, Joe Biden’s chief medical adviser Dr Anthony Fauci shared hopes that Omicron wouldn’t cause a big problem, but said preparation is still important while we learn the facts.
“The positive effect is to get us better prepared, to rev up on the vaccination, to be really ready for something that may not actually be a big deal, but we want to make sure that we’re prepared for the worst,” he said.
It’s still unclear how seriously the variant will impact the UK
Omicron seems to be rapidly increasing in southern African countries, and this suggests it is either “more infectious than previous strains, or that there is less immunity to it,” according to Dr Peter English, a retired consultant in communicable disease control.
However, we can’t necessarily look at the situation abroad and use it as a blueprint for what may happen here.
“These southern African countries are relatively poorly vaccinated, the world has done a shamefully poor job of ensuring that poorer countries are vaccinated, and most people in the populations in which it has spread are unvaccinated, so we do not know how the virus would behave in a more highly vaccinated population,” he said.
“It is quite possible that people who have had two or, better still, three doses of existing vaccines will be well protected against it. But it is also possible that we will have much less protection, from existing vaccines, against this new variant. We do not yet have enough information to know.”
Given all the uncertainties, Dr English believes the UK is right to take a “precautionary approach”.
Vaccines are still essential
Yes, we’ve been warned that the Omicron variant may evade some of the protection offered by the vaccine, but that doesn’t make vaccines redundant.
Professor Jim Naismith, director of the Rosalind Franklin Institute and Professor of Structural Biology at the University of Oxford, explained why.
“Based on scientific studies of various changes to Spike and our understanding of the structural biology of neutralisation, we would expect this variant to be less susceptible to immunity either from vaccine or previous infection,” he said.
“However, to use a football analogy, playing in the Cup Final, winning 5–0 is just as good as winning on penalties by one goal after extra time. The vaccines we have are safe and effective, they have massively reduced serious disease and death. They will be still be effective to some extent and I would urge everyone to get theirs.”
