At least one person has died in the United Kingdom after having been infected with the Omicron variant of Covid-19, Prime Minister Boris Johnson said on Monday, according to Reuters. This is the world’s first publicly confirmed death due to the new strain.

Johnson made the statement during a visit to a vaccination clinic in London. The British government has not given any information on whether the person who died was vaccinated or had any underlying medical conditions.

Johnson, however, said that Omicron now accounts for 40% of infections in United Kingdom’s capital.

“So I think the idea that this is somehow a milder version of the virus – I think that’s something we need to set on one side – and just recognise the sheer pace at which it accelerates through the population,” he told reporters.

The British prime minister said that the best thing people can do is to get their booster doses, the BBC reported.

On Sunday, he declared an “Omicron emergency”, and said that booster shots will be made available to all persons above 18 years of age in England from this week.

“No one should be in any doubt, there is a tidal wave of Omicron coming,” Johnson said. However, he added that a third dose of the Covid-19 vaccine can bring protection against the disease back up.

The British prime minister said the government has set a new target of offering boosters to all adults who want one by the end of December.

Meanwhile, the website of the United Kingdom’s National Health Service crashed on Monday as over 1,10,000 persons attempted to book a booster shot before 9 am Greenwich Mean Time, according to the BBC.

Long queues were also reported at walk-in centres.

Last month, the World Health Organization classified Omicron as a variant of concern. It said that preliminary evidence suggested an increased risk of reinfection with this variant, as compared to other variants of concern.

A “variant of concern” has the highest threat perception among other coronavirus variants because of its increased transmissibility, infectivity, or resistance to vaccines.

The Omicron variant was first detected in South Africa on November 24.