As the UK rides a new wave of Covid, we take a look at the variants causing infections, and what the future may hold.
What is the situation in the UK?
With mass testing over in the UK and surveillance programmes curtailed, information on whether infection levels are rising is largely based on data from the Office for National Statistics infection survey, in which swabs from randomly selected households are analysed.
While this survey picks up symptomatic and asymptomatic infections and is based on a random sample, it does have drawbacks. Among them, the headline results reflect all active infections – even if the infection began several days previously – and covers the previous week, meaning the latest data is two to three weeks behind the current situation.
According to the most recent figures, infection levels rose to about one in 30 people in England in the week ending 10 October, with the figure to the week ending 29 September reaching one in 25 in Wales. In Northern Ireland and Scotland, the trend was unclear, with about one in 40 people in the former and one in 35 in the latter thought to have had Covid that week.
However, data from pillar 1 testing and hospital figures suggests the tide may be turning.
While NHS figures for England have shown an increase in Covid patients being admitted to hospital in recent weeks, numbers are now declining, with 8,198 Covid patients admitted in the seven days ending 10 October, compared with 7,809 in the week ending 17 October.
What’s behind the latest rise?
While there are new variants on the block, the current wave was at least initially fuelled largely by variants we have seen before, suggesting other factors may be the main drivers.
These include colder weather, a return of children to schools, adults going back to work after summer, the relaxation of protective behaviours and waning immunity from vaccination or previous infections.
What is happening with variants?
Wearing a high-quality mask in crowded places can reduce the risk of contracting Covid. Photograph: Alberto Pezzali/AP
Unlike previous waves, which have been fuelled by particular variants – think Alpha, Delta and Omicron – the picture now is far more complex.
A big issue is that many new forms of Omicron are emerging, leading to the idea that this autumn and winter we could be facing an “Omicron soup”.
Among those thought to be important for the UK over the coming months are BQ.1.1 and BF.7 – both of which are forms of BA.5 – while BA.2.75.2 is another possible contender.
“As of now, around half of the new cases are variants from the June/July wave, and half are new variants,” said Alex Selby, an independent mathematician tracking the mix.
Prof Tom Wenseleers, an evolutionary biologist at the Catholic University of Leuven in Belgium,says BA.4, BA.5 and BA.5.2 infections are expected to reduce in the coming weeks, while the sharing involving other variants including BQ.1.1 are likely to rise rapidly from low levels.
Different variants could be important in different parts of the world, he adds. In Singapore and parts of Asia or Oceania, XBB is a big contender.
With variants cropping up so often, classifying them is becoming difficult. Wenseleers says he and others have begun grouping variants by “levels”.
“Those variant buckets are defined according to how many key beneficial mutations they have in the receptor binding domain of the spike protein of the virus – i.e. 4, 5 or 6 or more,” he said.
But he noted such variants still could have a large number of unique mutations, meaning it was unclear at present what level of immunity an infection with one variant offered against another.
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Experts say there are no obvious signs the new variants lead to more severe disease than previous variants, however the picture will become clearer over time.
What does this mean for the winter?
Some experts say that with the current wave involving some variants we have seen before, population immunity could help to keep the wave relatively small, although Wenseleers said it could be as large as the recent summer wave.
The ongoing autumn booster programme should ramp up protection against severe disease in the most vulnerable people, although the vaccines offer less protection against infection and such defence wanes rapidly.
Even if most people are protected against serious illness, the concern is that infection levels will grow this autumn and winter as a result of new variants taking hold – often with the ability to dodge our immune defences, at least to some degree.
“I would not be surprised by a double bump sort of [Covid] epidemic this autumn. This one now, primarily caused by BA5 and another one later caused by the next variant to take hold properly,” said Prof John Edmunds at the London School of Hygiene and Tropical Medicine. “We might already be in that second bump, but it is impossible to tell with our current surveillance.”
The NHS is feeling the pressure of a rise in Covid, while another concern is the disruption in sectors from travel to hospitality caused by staff taking sick leave. Such problems could be further compounded should the UK also face a difficult flu season – a concern early data suggests may well be borne out.
And what about Christmas?
While it is unlikely even a further wave of Covid will trigger new rules or restrictions, experts have been speaking out about personal actions that can be taken to reduce the risk posed by the virus. These include ensuring all those who are eligible come forward for their booster vaccinations, wearing a high-quality mask in crowded places, improving ventilation, and not visiting elderly or vulnerable people if you have symptoms of any respiratory illness.
How good are we at spotting new variants?
Earlier this year the UK was leading the way with sequencing virus samples. However, scaling back of PCR testing by the public has led to concerns the results may not be as representative, as samples now mainly arise from hospital settings.
“Levels of sequencing in the UK currently are somewhat stifling the ability to do a lot of the analyses we used to be able to do very rapidly,” said Dr Thomas Peacock of Imperial College London. “However to do sequencing also requires reactivation of testing.”
But Dr Meera Chand, the UKHSA director of clinical and emerging infection, said Covid variants continued to be monitored. “We continue to monitor Sars-CoV-2 variants together with partners around the world to ensure we can identify any emerging variants as soon as possible.