A new strain of coronavirus has worried scientists in the US and UK amid fears it could be spreading quicker than researchers can keep up with.
BA.2.86, unofficially dubbed Priola, was detected in Denmark in July, but in the following weeks it was found in several places all across the world and scientists struggled to link them.
This led to fears it could be far more prevalent than realised, although scientists have cautioned not enough is known about it to draw any definitive conclusions.
What is it?
Pirola, like previous variants, has been named using characters from the Greek alphabet in this case a combination of Pi and Rho.
The name is unofficial and has not been given a specific designation by the World Health Organisation like Alpha or Omicron.
Priola is a strain of Omicron and scientists are still assessing how dangerous it is.
It has not yet been classified as a "variant of concern" in the UK but scientists have expressed fears over the unusually high number of mutations within the strain.
So far scientists have said they are reasonably confident it is more infectious than Omicron, which at the time of its discovery in 2021 was considered far more transmissible than previous strains.
Francois Balloux, Professor of computational systems biology and director of the UCL Genetics Institute at University College London, said the new strain is "the most striking SARS-CoV-2 strain the world has witnessed since the emergence of Omicron" with more than 30 mutations.
Despite this, Prof Balloux said it is unlikely to cause a fresh wave of severe disease and deaths, or prompt fresh restrictions on people’s daily lives, because most people have some immunity to the illness.
High numbers of mutations can make a variant more transmissible than previous variants because it can help bypass natural immunity built up by previous Covid-19 infections.
This is what caused Omicron to spread so rapidly, and Priola is a variant of Omicron with an even higher number of mutations.
A key worry for scientists is how the Priola has been detected in numerous countries among people who have no connection with each other, suggesting it is far more widespread than we realise.
Where has it been found?
The first recorded incident of BA.2.86 was in Denmark on July 24.
Many nations have reduced the amount of Covid monitoring they carry out meaning fully tracking BA.2.86. isn't possible.
According to GISAID, which tracks Covid in the US, it has been found in 10 states.
They predict it makes up less than 2% of cases in the country, but this is up from 0.01% when it was first discovered in August.
It has also been detected in Sweden, South Africa, Israel and Canada.
It was identified in the UK on August 18.
In a health update issued by the UK Health Security Agency (UKHSA) on September 14, they said 37 cases of the strain had been detected in England, with 28 linked to an outbreak in a care home in Norfolk.
Seven of the 37 were admitted to hospital, but no deaths have been reported.
What has the response in the UK been?
In the UK this year's booster rollout was brought forward to September rather than October in response to the new variant.
The jabs are on offer to everyone over 65.
Dr Renu Bindra, UKHSA incident director, said that while BA.2.86 has a “significant number of mutations” compared with other variants circulating among the population, the data so far is “too limited to draw firm conclusions” about the impact this will have on the severity of the virus.
Covid hospital admissions have been rising steadily in the UK for months, but this trend started before BA.2.86 was detected.
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