A highly contagious Covid variant is currently spreading rapidly in the UK, according to official data indicating a significant increase in infections over the past month.

The UK Health Security Agency (UKHSA) reported that the 'Nimbus' strain, scientifically known as N.B.1.8.1, accounted for eight per cent of Covid tests that were positive at the beginning of June, up from four per cent in mid-May. Experts believe Nimbus is the most contagious variant to date and could potentially lead to a surge in new cases during the summer.

Recent data from the agency also shows a rise in the overall percentage of positive Covid tests to 6.8 per cent as of June 15, marking the highest level recorded this year compared to 5.6 per cent in the previous month.

Despite these figures, health officials warn that the actual spread of Nimbus and Covid in general may be underestimated due to reduced testing compared to the peak of the pandemic.

Furthermore, the UKHSA's weekly report revealed a slight increase in hospital admissions for Covid, with just over 1.5 admissions per 100,000 people.

Scientists in the UK have previously cautioned about the potential for Nimbus to cause a surge in Covid cases, as immunity from previous infections and older vaccines may have waned, leaving individuals more susceptible to illness.

Laboratory studies indicate that Nimbus can infect human cells more efficiently than previous strains and may have an increased ability to evade the immune system, making it more transmissible. However, there is currently no evidence suggesting that Nimbus is more likely to cause severe illness or death compared to other variants.

Common symptoms associated with Nimbus include fatigue, fever, muscle aches, sore throat, and swollen neck glands. Health experts emphasize that existing Covid vaccines, which have been adjusted to target Omicron descendants, are expected to remain effective against Nimbus.

Although Nimbus is on the rise in the UK, it still represents a minority of total Covid cases, with strains LP.8.1.1 and XFG being the most prevalent variants. The World Health Organization reported that Nimbus accounts for 10.7 per cent of global Covid infections, up from 2.5 per cent in May.

Despite the availability of vaccines, only 59 per cent of individuals over 75 in England have received the Covid vaccine, while uptake among younger individuals with compromised immune systems remains low. Vaccine companies are currently updating their shots to target the Nimbus strain, with Moderna expecting to release an updated mNEXSPIKE shot by fall.

Originating from China, Nimbus has been linked to a rise in cases and emergency room visits in the US, where it now comprises over a third of Covid cases. The name 'Nimbus' was coined by Canadian evolutionary biologist T Ryan Gregory, who has named various popular variants.