Shock as Mpox mutates AGAIN – new variant is highly transmissible, concerned experts warn
Health officials have sounded the alarm over a new mutant ‘highly transmissible’ mpox strain, believed to be behind a wave of fresh cases.
A newly discovered variant of the rash-causing virus is now spreading in the Democratic Republic of Congo (DRC), experts say.
It is a descendant of the deadlier clade 1a strain of mpox, formerly known as monkeypox, which is estimated to kill up to 10 per cent of patients — far more than other strains that have spread in recent months.
Officials are worried because the new version carries a mutation known as APOBEC3 which makes it more infectious than its predecessor.
Scientists say the same mutation has already been seen in the Clade 1b mpox strain, which has spread far beyond Africa to the UK, Europe and Asia within the last year.
Experts have warned that swift action from the international community is needed to help stop any potential larger mpox outbreak of the new variant outside of DRC.
Latest World Health Organisation (WHO) data shows more than 2,063 mpox cases have been logged in the nation in 2025 alone, including four deaths.
However, it is unclear exactly how many cases, and deaths, the new mutant Clade 1a strain accounts for, with older versions still circulating.
The strain is a descendant of the deadlier clade 1a strain of mpox, formerly known as monkeypox, which is estimated to kill up to 10 per cent of patients — far more than other strains that have spread in recent months
In a briefing Dr Ngashi Ngongo, head of the mpox incident management team at the Africa Centres for Disease Control and Prevention (Africa CDC), said: ‘We have seen a new variant of Clade 1a with APOBEC3 that has been detected, and unlike the old 1a variant, this one has got high potential for higher transmissibility.’
The WHO also says: ‘The current understanding is that Clade 1 leads to more severe disease and death than Clade 2 in the populations where it is endemic.’
Most Clade 1a infections have been linked to spillovers from animals, with limited human-to-human transmission in close-contact settings like households observed.
Clade 1a has a fatality rate ranging from 1.4 per cent to over 10 per cent, far more than the 0.1 per cent and 3.6 per cent recorded for Clade 2.
Research published in January in the New England Journal of Medicine, suggests the Clade 1b rate stands around 3.3 per cent.
But Dr Lorenzo Subissi, a virologist with the WHO Health Emergencies Programme, told The Telegraph that higher fatality rates haven’t been observed, so far, with the new Clade 1a strain.
While this variant may spread outside of DRC, the mortality rate seen in Kinshasa, where the new Clade 1a variant co-circulates with Clade 1b, remains less than one per cent, so much lower than what was historically thought to be clade 1a mortality,’ he said.
‘Mortality will largely depend on underlying conditions of the affected population such as malnutrition.’
Experts are worried because the new version, which carries the mutation known as APOBEC3, has evolved to be even more infectious than its predecessor. Pictured, a medic in DRC recording information from an mpox patient in September
Cases of Clade 1b in the UK are a far cry from the 2022 outbreak where thousands of cases were recorded, mostly in London
The discovery of the new mutant strain came as the WHO extended its declaration of the ongoing mpox epidemic as a ‘public health emergency of international concern’.
The designation — the same one the UN agency gave Covid in late January 2020, just a few weeks before the virus ripped across the world — was put in place last August amid a rise in Clade 1b cases.
The unanimous decision from the WHO emergency committee was ‘based on the continuing rise in numbers and geographic spread, the violence in the eastern DRC, which hampers the response, as well as a lack of funding to implement the response plan,’ it said in a statement.
The outbreaks in Africa mainly involve Clade 1a and 1b strains of the virus, with limited transmission of clade 2.
Dr Ngongo said several countries in Africa are continuing to report rising mpox cases, while spiralling armed conflict in the DRC is increasing the risk of spread.
Clade 1b has also spread outside of Africa, with cases in countries including the UK, US, Sweden, Thailand, India and Germany.
To date, nine cases of the strain have been spotted in Britain, but the ‘risk to the UK population remains low’, the UK Health Security Agency says.
However, the virus has swept through central Africa killing at least 1,000 people, since the outbreak began.
Mpox causes characteristic lumpy lesions, as well as a fever, aches and pains and fatigue.
However, in a small number of cases, it can enter the blood and lungs, as well as other parts of the body, and becomes life-threatening.
