UKHSA warns of increase in mpox cases in London and the North West
Public health officials have warned of an increase in cases of mpox in England, particularly in London and the North West.
In a briefing note to NHS staff, the UK Health Security Agency (UKHSA) has warned clinicians to be aware of the increased risk for some groups and consider the possibility of mpox when patients present with symptoms.
Clinicians also need to be aware that clinical features may be less florid in those who have been vaccinated or had previous infection, it said.
‘UKHSA plans to reissue advice to communities most at risk, remind clinicians to remain vigilant, and improve coverage of two doses of vaccination for those eligible,’ the letter stated.
In England, there were 56 clade II cases in January 2026 compared to a monthly average of 20 across 2025.
There have already been 47 cases in the first two weeks of February, figures show.
Infections are predominantly occurring in gay, bisexual and other men who have sex with men (GBMSM), with some linked to sex-on-premises venues, the letter said.
Most cases are clade IIb, but in the past six weeks there has also been an increase of clade Ib cases in London with six reported in GBMSM including some who have not travelled, UKHSA said.
Cases among women and heterosexual men remain associated with travel from countries with longstanding endemic mpox, mainly in the African continent, the Agency advised.
In 2025, at-risk groups in the UK were urged to take up the offer of mpox vaccination due to the spread of the clade Ib variant in Europe.
Clade Ib mpox, has more severe symptoms than clade II mpox which was responsible for the 2022 global outbreak and appears to be more contagious with outbreaks in several African countries.
At the time, small numbers of clade Ib mpox had been identified in the USA, Spain, Italy, the Netherlands and Portugal which were not associated with travel to countries with known transmission, suggesting community transmission.
UKHSA said currently there do not appear to be differences between the clades in terms of severity among cases in England.
A routine immunisation programme for gay, bisexual and other men who have sex with men at higher risk is being delivered through sexual health services.
‘Whilst it is expected that the UK’s high coverage of pre-exposure vaccination among eligible GBMSM will protect against another large outbreak of mpox, it is still possible that an increase in transmission will be observed,’ the letter said.
NHS England announced in January last year that it was expanding access to mpox vaccination for high-risk groups after delivery of new vaccine stocks.
In December, UKHSA identified a new recombinant strain of mpox in an individual who had recently travelled to Asia.
Genomic sequencing showed the strain contained elements of clade Ib and IIb mpox, which the Agency said was not unexpected given both are currently circulating.
Dr Katy Sinka, head of sexually transmitted infections at UKHSA, said: ‘We’re seeing an increase in mpox cases so far in 2026, which a reminder that this unpleasant illness hasn’t gone away.
‘If you’re eligible, the mpox vaccine is now available routinely as part of your sexual healthcare alongside STI and HIV testing, screening and other vaccines.
‘It’s one of the best ways to protect yourself against mpox and reduces your chances of becoming severely unwell if you do catch it. Make sure to get both doses to get maximum protection.’
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