Omicron: How dangerous is the new Covid variant?

New variant spreading fast and causing concern but infectious disease experts say more time and data needed to ascertain full extent of threat it poses

The omicron variant of coronavirus, which first emerged in southern Africa towards the end of November, has now spread to at least 55 countries around the world, including the UK.

A further 249 infections from the latest strain of Covid-19 were detected in Britain on Thursday, taking the total to 819, according to the UK Health Security Agency, its arrival having already forced Boris Johnson’s government to reintroduce social restrictions for the first time since “Freedom Day” on 19 July.

The UK’s already high but stable infection rate has meanwhile begun to climb in the run-up to Christmas and it is feared that a winter spike of the kind we saw in the aftermath of the 2020 festive season could once more threaten to overwhelm the NHS and perhaps prompt the need for even tighter “Plan C” measures.

However, while the omicron variant is thought to be more transmissible than the delta variant, currently still the dominant strain in the UK, the truth is that more “real-world” data is still needed before the extent of the threat it poses can be determined.

What we do know about the variant at this early stage is as follows.

UK scientists first became aware of it on 23 November when samples from South Africa, Botswana and Hong Kong were uploaded to a coronavirus tracking programme, although subsequent examination of its genetic sequencing has indicated it could have first appeared in mid-October.

The World Health Organisation (WHO) - alarmed by the 32 mutations to omicron’s spike protein, suggesting it might have the potential to evade the suite of Covid vaccines currently available - moved to declare it a “variant of concern” on 26 November.

That anxiety was echoed by England’s deputy chief medical officer, Professor Jonathan Van-Tam, when he told a press briefing on 29 November: “The number of mutations present, already on first principle, makes us worry about a possible effect on vaccine effectiveness.”

One of the difficulties with the variant is that, at present, only a PCR test - which, unlike a lateral flow, is sent off to a laboratory for examination - can determine which particular variant of coronavirus a sufferer has contracted, a process that can take up to 14 days.

The fact that omicron’s symptoms appear to be mild and that Covid already shares similarities with the common cold like blocked noses, sore throats and headaches further complicates diagnosis.

But so far, at the time of writing (10 December), no one is recorded as having died as a result of falling ill with the omicron variant, with the European Centre for Disease Prevention and Control confirming as much in its latest update, recording 402 cases in the European Union and 1,378 more around the rest of the world.

Statistically though, it can only be a matter of time before that changes.

“There is still not enough information to make a definitive evaluation of the variant, but each day we learn more,” Dr Amesh Adalja, an infectious disease expert with the Johns Hopkins Center for Health Security, told Prevention.

“It’s unclear how ‘deadly’ this variant is, because there have not been any reported deaths thus far, but deaths lag.”

Speaking specifically about the situation in the UK, Professor John Edmunds, a member of the government’s Scientific Advisory Group for Emergencies (Sage), told a Royal Society of Medicine briefing this week he was confident Britain would see a “really rather large wave of omicron” and deaths in the next few months and warned that the virus would keep evolving to escape immunity.

“We’re getting large numbers of cases and that will result in a large number of hospitalisations and, unfortunately, it will result in a large number of deaths, I’m pretty sure of that,” Professor Edmunds said.

“What happens next? It’s pretty clear the virus hasn’t done with evolution. It’s going to continue to evolve. I’ve long thought that what we’ll start to see is that the virus evolves towards being more of an immune escape than necessarily more transmissible.”

The expert branded the need for social restrictions like those reintroduced by Mr Johnson and other political leaders in Western Europe as “a necessary evil”, conceding that they are “very damaging for parts of the economy, the hospitality sector, retail sector in particular” but insisting: “Unfortunately, we have to do it. The rate at which this virus is spreading is doubling every two or three days.”

Professor Edmunds echoed the UK government’s call for the public to get their vaccine booster jabs, which the prime minister had hoped would be sufficient to keep the virus at bay this winter before the sudden emergence of omicron forced his hand.

That raises questions about how effective our existing vaccines are likely to be against the new strain.

Results from preliminary studies by the German Centre for Infection Research found that there were significant reductions in antibody potency for the Pfizer/BioNTech, Moderna and Oxford/AstraZeneca vaccines when they came up against omicron.

However, two doses of any of those vaccines should offer some protection from severe disease according to the WHO, which has said that “current vaccines remain effective against severe disease and death”.

Manufacturers have meanwhile pledged to work “at full speed” towards producing an omicron-specific inoculation and hope to have a version in place by March 2022.