WHO declares ‘public health emergency’ over new clade of mpox that’s spreading rapidly

New mutant strain has a higher fatality rate, spreads without sexual contact and infects healthy children as well as adults

The World Health Organisation (WHO) has declared an international public health emergency to combat a new fast spreading outbreak of mpox sweeping East and Central Africa.
The UN body issued its highest level alert after a unanimous decision by scientists monitoring the escalating flare-up of the virus formerly called monkeypox.
Thousands of mpox cases and hundreds of deaths have been recorded in the Democratic Republic of Congo (DRC) in 2024 and in recent weeks infections have begun spreading to neighbouring countries.
The scale of the outbreak, and the potential for it to spread across the continent and beyond, have led the WHO to announce the eighth public health emergency of international concern (PHEIC) of the past two decades.
This year’s explosion in cases in the DRC was “something that should concern us all,” said Tedros Adhanom Ghebreyesus, director general of the WHO, as he announced the alert.
A PHEIC declaration is designed to help marshal resources for “extraordinary events” where the cross-border spread of a disease needs to be tackled with international action.
DRC has already recorded nearly 15,000 suspected cases with 511 deaths so far in 2024, and the spread and surge in cases has left many public health officials worried the virus may soon jump further afield.
The emergence of a new mutant strain, or clade, and indications that the virus is getting better at spreading from person to person have added to concerns.
Dr Tedros said: “The detection and rapid spread of a new clade of #mpox in eastern #DRC, its detection in neighbouring countries that had not previously reported mpox, and the potential for further spread within Africa and beyond is very worrying.”
Mpox is spread by physical contact and causes a characteristic lumpy rash, fever, aches and pains and in some immune-compromised patients can be fatal.
The first human case was detected in northwest DRC in 1970 when a nine-year-old boy developed a nasty rash that reminded medics of smallpox. Scientists have since identified two different clades in Africa.
Clade 2 is found in West Africa and in 2022 sparked a global epidemic and its own PHEIC, when it spread to more than 100 countries, predominantly affecting gay and bisexual men.
However the strain at the centre of the current alert is clade 1. Outbreaks of clade 1, which has a higher death rate, were at first often limited to a few households in remote areas and associated with families killing and eating wild forest animals, known as bushmeat.
Scientists have, however, been warning that annual cases of clade 1 in DRC have been rising steadily for years. And as numbers have risen, researchers confirmed a new strain, named clade 1b, in eastern DRC early this year.
Medics in the region report that during late 2023, they saw a spike in mpox patients with severe symptoms – including widespread lesions, high fevers, and a higher death rate. It does not require sexual contact to spread and has infects children as well as adults.
“I knew this was something different because the symptoms were so different from clade 1 – what we normally see in the DRC,” said Dr Leandre Murhula Masirkika, a local scientist who has pioneered research on the ground.
“We are seeing a lot of deaths, a lot of miscarriages, and rapid transmission through the community.”
Dr Masirkika and a small team of local researchers traced the first case of clade 1b back to a bar in Kamituga and a single patient – a local barman.
The man, said to be a pimp, regularly had intercourse with female sex workers. In September, he had intercourse with three women at the same time – all of which shortly afterwards presented to the hospital with a severe form of the disease.
Since then, thousands of patients have presented at clinics and hospitals in South Kivu with severe symptoms, including many children. According to Dr Masirkika, the death rate is as high as 5 per cent in adults and 10 per cent in children – compared to just 0.2 per cent for clade 2.
Understanding the dynamics of the new strain and the outbreak have been clouded by a lack of sequencing and because the original clade 1 strain also seems to be surging.
Piero Olliaro, professor of poverty-related diseases at Oxford, said: “These are two parallel outbreaks of two variants with different modes of transmission and at-risk groups, thus requiring different strategies for containment. They also differ in morbidity and mortality.”
Seven in 10 of DRC’s cases are children, and the disease is rife in overcrowded hospitals, Save the Children said this week.
Jacques, an epidemiologist and mpox expert with the charity in South Kivu, said: “The worst case I’ve seen is that of a six-week-old baby who was just two weeks old when he contracted mpox and has now been in our care for four weeks.
“He had rashes all over his body, his skin was starting to blacken, and he had a high fever. His parents were stunned by his condition and were scared he was dying.”
Yet it is the virus’s potential to spread across borders quickly that has most alarmed international health experts. Eastern DRC has extensive trade links with neighbouring countries and is also a hub for international aid workers.
In late July, a 42-year-old Kenyan long-distance lorry driver became that country’s first ever mpox case. He was taken ill after driving from Kampala to Mombasa and his infection was identified as the new clade 1b strain.
Burundi at the same time recorded its own first cases, as did Rwanda, among traders who frequently travelled to DRC. Both countries confirmed the cases as clade 1b. Uganda has also reported cases.
Trudie Lang, professor of global health research at Oxford, said: “The risk of it moving is big. There’s the case in Kenya where a trucker brought it in, and people can get on a plane with it. This is what I’m most worried about because the cases we know about are the ones that have been very sick and coming to hospital, but what we don’t know is how many people have a milder infection.”
Dr Tedros said earlier this week that the emergence of clade 1b and its spread, apparently mainly through sexual networks, to neighbouring countries was the main reason he was considering a PHEIC.
“In the past month, about 90 cases of clade 1b have been reported in four countries neighbouring the DRC that have not reported mpox before: Burundi, Kenya, Rwanda and Uganda.
“But we are not dealing with one outbreak of one clade – we are dealing with several outbreaks of different clades in different countries with different modes of transmission and different levels of risk.”
A PHEIC has only been declared seven times since 2009: over H1N1 swine flu, poliovirus, Ebola, Zika virus, Ebola again, Covid-19 and mpox.
“This is a very, very bad situation,” Dr Masirkika told The Telegraph. “The virus is now in 26 regions of the DRC and in border countries including Uganda, Burundi, and Rwanda.”
“I believe it will very easily spread elsewhere, particularly because people regularly travel from Goma – where there are currently cases – to Europe via the international airport there,” he said.
“This is the most dangerous clade of mpox we have ever seen,” he added.
Protect yourself and your family by learning more about Global Health Security