How worried should we be about Omicron? What we know so far - and what we don’t

Is the arrival of Omicron the nightmare before Christmas, or is the alarm about the most mutated variant of Covid-19 so far overstated?

That’s the question dominating the national conversation this week, as the Government scrambles to tighten rules - in a “proportionate” way, as they keep stressing - to restrict the spread of the B.1.1.529 variant.

At this stage, it’s too early to say with any certainty how effective the vaccines will be against Omicron, or whether it’s any more deadly than the dominant Delta strain.

In his press conference today (29 November), England’s deputy chief medical officer Professor Jonathan Van-Tam advised against panic and, in typical fashion, used an analogy to explain the situation: “We look at South Africa, it’s our kind of weather forecast here – in the same way the weather forecasters have warned us about Storm Arwen in the recent few days. You can’t ignore what you see around the world and it is more urgent than ever before, because of what’s happened.”

So what is the forecast on Omicron, and what will it mean for Christmas (and beyond)?

Is Omicron more transmissible?

There were early warnings that the variant could be more transmissible, given how quickly it had spread in South Africa’s Gauteng province - where up to 90% of new cases are already Omicron.

The reason why many scientists believe it can spread faster is that ten of its 30 or so mutations are on the “spike” protein - the part of the coronavirus that acts a bit like a lock pick, changing shape to allow the virus to latch on to human cells.

However, the World Health Organization (WHO) has said that it is still too early to know for sure. “It is not yet clear whether Omicron is more transmissible compared to other variants, including Delta,” they said. “The number of people testing positive has risen in areas of South Africa affected by this variant, but epidemiologic studies are underway to understand if it is because of Omicron or other factors.”

Does Omicron cause more severe illness?

There are also conflicting reports on the severity of the disease caused by Omicron. Dr Angelique Coetzee, the doctor who first spotted the new variant, said that patients have so far had “extremely mild symptoms” - although this may be due to a younger population.

The WHO also says “it is not yet clear” whether Omicron is any more severe, and that increasing hospitalisation rates in South Africa may be due to increasing case rates, rather than the variant itself.

Will the vaccines work against it?

The biggest question is whether Omicron can bypass immunity - whether that’s from the vaccine or previous infection.

Professor Van-Tam said that the “number of mutations present, already on first principle, makes us worry about a possible effect on vaccine effectiveness” - although he was quick to stress that that there “are far more things we don’t know yet, than things we do know”.

Most scientists are expecting that we’ll have answers about vaccine efficacy against Omicron in two to three weeks - just before Christmas, in other words.

If a new vaccine is required, then all of the major pharmaceutical companies say they can develop tweaked vaccinations for Omicron.

Director of the Oxford Vaccine Group, Professor Sir Andrew Pollard, was optimistic when talking to the BBC, saying that most of the mutations in Omicron are in similar regions seen in other variants so far.

“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 said. “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.”

Do PCR tests detect Omicron?

In its update on the variant, the WHO confirmed that PCR tests “continue to detect infection, including infection with Omicron”.

There’s actually reason for cautious optimism on testing. Omicron, like Alpha before it, has the “S-gene dropout”, which is a clear differentiator from the dominant Delta variant that spread so rapidly around the world.

This means that PCR tests can easily detect the Omicron variant, which gives scientists a clear picture of where it is, and how it’s spreading.

More questions than answers for now

To return to our original question, it would seem that tightening restrictions in a proportionate way is a sensible response to a variant that we still know so little about.

It is too early to say for sure how Omicron is going to affect our Christmas plans, and what impact it could have on 2022, but the pandemic has taught us that “hope for the best, prepare for the worst” is a prudent strategy.

Professor Van-Tam used yet another analogy to sum up his take on where we are now. “Omicron is like now picking up a couple of yellow cards to key players on top,” he said. “We may be OK but we’re kind of starting to feel at risk that we might go down to 10 players, and if that happens – or it’s a risk that’s going to happen – then we need everyone on the pitch to up their game in the meantime.”

In the UK we are lucky to live in a country with one of the highest vaccination rates globally, and a booster programme that is now being rolled out to all over 18s.

But the emergence of Omicron in southern African is a stark reminder that until we vaccinate the world against Covid, the pandemic is far from over.

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