Will the omicron Covid variant wreck Christmas?

Judging by my mailbox, there is only one Covid question on people's minds at the moment – will omicron ruin Christmas? Well, that and various technical questions about the appropriateness or otherwise of "consensual stranger snogging".

On the main event, what people want to know is will there be another lockdown? Will Boris Johnson suddenly lunge from Plan A to Plan C in an 11th-hour bid to "save the NHS" as he has done twice before? Already, those over 75 have been asked to help their GPs by staying away from routine appointments.

The data on omicron emerging from South Africa provides some important pointers but not the answer. It shows the variant is spreading very rapidly in the community, with cases up from around 300 three weeks ago to nearly 7,000 on a seven-day rolling average.

The pattern is the same in several different regions, which suggests it is something inherent to the virus is driving it rather than a local oddity in the environment or people's behaviour. It is clear, too, that large numbers of people who have had Covid are being reinfected.

"Population-level evidence suggests that the omicron variant is associated with substantial ability to evade immunity from prior infection," a study published on Thursday noted.

"Urgent questions remain regarding whether omicron is also able to evade vaccine-induced immunity and the potential implications of reduced immunity to infection on protection against severe disease and death."

Last week, The Telegraph was first to report that GPs in South Africa were seeing many "mild" cases of Covid, which they believed to be caused by omicron. This remains the case – but the new variant, just like the others before it, can also cause serious disease.

This is evident from hospital admissions in Gauteng, which have been rising faster than in any previous wave. Over the last week, there have been over 1,000 hospital admission in the province – nearly quadruple the number recorded two weeks ago.

Prof Rudo Mathivha, an intensive care specialist, painted a grim picture from inside Chris Hani Baragwanath Academic Hospital, in the vast Soweto township on the outskirts of Johannesburg.

"A 15-year-old died this morning. He was a new Covid-19 admission and developed pneumonia," Prof Mathivha told The Telegraph on Friday. "We shouldn't be seeing these kinds of numbers this early in the wave.

"We should not be seeing a young child who is moderate to severely symptomatic needing supplementary oxygen or high care intervention. It is this which is worrying me."

The alpha and delta variants turned out to be more deadly than the original Wuhan virus. We will find out eventually if the same is true of omicron but it will take more data and more time.

The next big news item around omicron will almost certainly centre on its ability or otherwise to evade vaccine-induced antibodies in laboratory tests. Scientists have been working on this in labs around the world for over a week, and we can expect the first results very shortly.

The headlines are unlikely to be good. Most experts think the virus will be able to evade vaccine-induced antibodies in the lab. Indeed, the UK Health Security Agency's latest risk assessment already puts omicron in the red zone for "vaccine-acquired immunity", albeit with a low level of confidence.

But as Dr Muge Cevik, an infectious diseases expert at the University of St Andrews, has pointed out, lab tests are far from conclusive as far as human immunity is concerned. Omicron may evade antibodies in test tubes, but vaccine-induced T-cells could still protect us.

"While [antibody] studies will likely give worrying results, once we start to get some real-world studies into how things are doing my guess is that vaccines will still be doing a decent job in protecting people from getting sick," she said.

The UK is much better vaccinated than South Africa, where just 25 per cent of the population is fully jabbed.

Another positive is that omicron may not spread as quickly when up against delta, the dominant variant in the UK. On the other hand, this may be a forlorn hope if the variant is able to reinfect Britons at the same rate it is reinfecting South Africans.

"If, as appears increasingly likely, omicron can infect people that other variants can't, then it will grow very quickly," tweeted Graham Medley, the head of the Government's SPI-M modelling group on Saturday.

So what does all this mean for Christmas?

If I was forced to bet on it (never a good idea), I would guess that omicron will spread rapidly in the UK but will not, for the most part, cause serious disease in those who are fully vaccinated and boosted.

To put a timeframe on this, I would go with Trevor Bedford, a virologist at the Fred Hutchinson Cancer Research Center in Seattle, who calculates that it takes about eight weeks from arrival for omicron to manifest itself as a serious epidemic.

For the UK, that would take us to mid to late January, which avoids Christmas. But, before getting the party hats out, consider two more important facts.

In the words of the epidemiologist Adam Kucharski: "A SARS-CoV-2 variant that's 50 per cent more transmissible would in general be a much bigger problem than a variant that's 50 per cent more deadly." This is a simple, if counterintuitive, matter of maths – more infections mean many more hospitalisations overall.

"Emerging evidence suggests omicron spreads easily, whether because inherently more transmissible and/or it reinfects more easily. So even if immunity against severe disease fully holds up, countries could face a much faster, larger peak than delta would have caused," said Prof Kucharski.

It is in this context that Mr Johnson will have to consider the NHS and the risk of it being overwhelmed.

Admissions have come down in recent weeks but are now flatlining, with 7,373 Covid cases in hospitals across the UK, including 895 in intensive care as of Saturday. In short, the system continues to run hot – with the worst weeks of January still to come.

Already there are scary-looking charts of omicron's UK growth doing the rounds on social media. Cases are climbing from a low base but there is community transmission and we are likely to see rapid growth ahead of Christmas if we follow South Africa's trajectory.

Ultimately, the question for the Prime Minister is this – how much growth, and therefore risk, can he and the NHS tolerate?

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