The UK Health Security Agency (UKHSA) said on Friday the first case of COVID-19 variant BA.2.86 had been detected in the country in an individual with no recent travel history.

The variant has also been identified in Israel, Denmark and the United States.

Speaking with The Guardian Dr Meera Chand, the deputy director of UKHSA, said: “We are aware of one confirmed case in the UK. UKHSA is currently undertaking a detailed assessment and will provide further information in due course.”

According to a risk assessment published on Friday by UKHSA, the case detected in the UK has no travel history, suggesting established international transmission and a degree of communication within the country-with more information on UK transmission is expected in the next week or two.

It said the similarity of genetic sequences in different countries implied a relatively recent emergence and rapid growth, although this remained a probationary analysis given the small number of sequences.

It added that current data is not enough to assess the relative severity or degree of immune escape of BA.2. 86 compare to other variants in circulation. The World Health Organization announced on Thursday it was designating BA.2.86 as a “variant under monitoring”.

The World Health Organization and US health authorities said Friday they are closely monitoring a new variant of Covid-19, although the potential impact of BA.2.86 is currently unknown.

The WHO classified the new variant as one under surveillance “due to the large number (more than 30) of spike gene mutations it carries”, it wrote in a bulletin about the pandemic late Thursday.

So far, the variant has only been detected in Israel, Denmark and the United States. The US Centers for Disease Control (CDC) confirmed it is also closely monitoring the variant, in a message on the social platform X, formerly known as Twitter.

There are only four known sequences of the variant, the WHO has said.

“The potential impact of the BA.2.86 mutations are presently unknown and undergoing careful assessment,” the WHO said.

The WHO is currently monitoring upwards of 10 variants and their descent lineages.

Most countries that had established surveillance systems for the virus have since dismantled operations, determining it is no longer as severe and therefore could not justify the expense - a move the WHO has denounced, calling instead for stronger monitoring.

In the last reporting period between July 17 and August 13, more than 1.4 million new cases of Covid-19 were detected and more than 2,300 deaths reported, according to a WHO statement.

The case load represents a rise by 63 percent from the previous 28-day period while deaths were down by 56 percent.

As of August 13, there were more than 769 million cases of Covid-19 confirmed and more than 6.9 million deaths worldwide, although the real toll is expected to be much higher because many cases went undetected.