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COVID-19: Omicron could also be extra infectious – however do we have to fear if it causes much less extreme illness? | UK Information

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As Boris Johnson informed his cupboard on Tuesday morning, the early data round Omicron seems to counsel that the brand new variant is extra transmissible than Delta – which for now stays dominant within the UK and world wide.

Nonetheless, the opposite early indication is that it additionally appears to end in much less extreme illness and finally fewer hospitalisations per case, in line with consultants like Dr Anthony Fauci, chief medical advisor to the US president.

Once more, this judgement is predicated on very early data that’s topic to vary, but it surely seems like excellent news.

Sadly, it isn’t that easy.

Even when the variant does show to be much less harmful than Delta or different strains, a better transmission fee can nonetheless have an actual impression on public well being and the quantity of people that turn out to be significantly unwell.

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Let’s clarify why.

For the final month or so the UK has been hovering above and beneath about 40,000 new {cases} per day. The R fee – the variety of new individuals contaminated by every particular person with an energetic an infection – has additionally been hovering round 1.

This implies every particular person with COVID has given COVID to a median of 1 different particular person. That is why the case-numbers have remained comparatively static – the 40,000 individuals with COVID are giving COVID to about 40,000 new individuals, who’re doing the identical with 40,000 extra individuals and the chain continues.

Over the same period, daily hospital admissions have been around 800. Meanwhile daily deaths have been around 135.

Put rather crudely, that means that about 1 in 50 people who get infected with the current dominant strain end up in hospital. Of those, about 1 in 6 sadly die. These ratios aren’t exactly perfect but they help with the maths later on so let’s work with them for now.

If the dominant Delta strain suddenly became half as dangerous overnight, while remaining exactly as transmissible as it has been, we would expect hospitalisations to drop to about 400 per day and remain there. 1 in 100 infections result in a hospitalisation. Deaths would end up just under 70.

However, if this new less dangerous variant was actually more transmissible, the impact in terms of the number of hospitalisations could end up worse.

A more transmissible variant has a higher R number. At the peak of the pandemic the R rate reached an upper estimate of about 1.5. That means that every 10 people with COVID would infect 15 others, every 40,000 would infect 60,000.

As it keeps the maths pretty simple as well, we’re going to use that for our calculations – that’s not a measured estimate of what Omicron might force R to rise to, or even a loose guess.

Some scientists have estimated that it may rise above this level, but we don’t know yet. We’re just using it to try and explain the relationship.

So if the R rate was to suddenly rise to 1.5, while the ratio of hospitalisations and deaths stays at the lower level – half of what it has been for the past few months, let’s take a look at what that would mean for the health service and public health.

After about a week we’d expect the infection level to be about 60,000. If 1 in 100 go to hospital that’s 600. If one in 6 of these people die that’s 100 deaths. These are both lower than the current figures, so good news.

But, the nature of R means that each of these now 60,000 daily cases will also infect an extra 50% of people, so 60,000 cases would soon become 90,000, more than double the number we’re currently seeing – and it would keep growing.

Despite the variant being half as dangerous as the original one, 90,000 daily cases would result in around 900 people needing some hospital treatment and cause 150 deaths.

A week or so later, 135,000 cases would see about 1,350 hospitalisations and more than 200 deaths.

These numbers are entirely made up, and the facts as we have them at the moment are that we don’t know how much more transmissible Omicron is.

We know even less about whether it is less dangerous on a case-by-case basis.

But it would have to be less dangerous by a much greater degree than it is less transmissible if we are to avoid a rise in the number of people needing hospital care.

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Evaluation by Thomas Moore, science correspondent

The maths on Omicron appears to be like actually horrible. Scientists have informed Sky Information that it in all probability accounts for 1% of {cases} proper now – about 500 a day.

Delta is much extra frequent. However the brand new variant is ready to unfold a lot quicker, with the quantity doubling each three to 4 days. By the tip of the 12 months, we’re more likely to go 100,000 {cases} a day.

From the primary seeds of the outbreak being sown by returning travellers, it might take simply six weeks for Omicron to turn out to be the dominant pressure. Its exponential rise is right down to its mutations.

On paper, they might assist it infect cells extra simply. And proof thought-about by scientists on the federal government’s SAGE committee suggests airborne transmission could also be extra frequent than with earlier variants.

The mutations additionally assist Omicron evade our antibodies. Analysis from South Africa suggests the re-infection fee is 3 times greater than in earlier waves. The wall of immunity that proved so strong in opposition to Delta is not wanting so safe any extra.

There’s hope, although. Whereas antibodies and T-cells from the vaccine or earlier illness are much less efficient at stopping an infection, they do nonetheless appear to guard in opposition to critical signs.

{Cases} in South Africa are typically milder than within the Delta wave. However hospital admissions are nonetheless rising. Even when only a small fraction of infections end in critical illness, excessive case charges imply numerous individuals nonetheless needing remedy.

The Omicron wave could not come at a worse time for the NHS. Even in a traditional 12 months, the start of January is its busiest interval. However this time hospitals might should think about probably the most infectious variant but, hovering in the direction of an eye-watering peak.

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