What we know so far about the new mpox outbreak

The Philippines on Monday, Aug. 19 reported its first case of mpox this year, but the Department of Health was still determining whether it was the new and dangerous variant sparking global alarm.

The 33-year-old Filipino man who contracted the virus had not travelled outside the country, the health agency said in a statement. His case was reported by a government hospital on Sunday, Aug. 18.

A deadly and more transmissible strain of the virus known as Clade 1b has killed hundreds of people in the Democratic Republic of Congo and been detected in Sweden and Pakistan in recent days. 

The World Health Organization last week declared the mpox surge a public health emergency of international concern, its highest alert level. It's the second time the WHO has issued its public health emergency warning since the epidemic first spread around the world in 2022.

What is mpox?

The disease, formerly known as monkeypox, was first detected in humans in the DRC in 1970.

There are two subtypes of the virus: clade 1 and clade 2. The deadlier clade 1 has been endemic in the Congo Basin in central Africa for decades. The less severe clade 2 has become endemic in parts of West Africa.

Mpox can spread human-to-human through sexual or close physical contact. Symptoms include fever, muscular aches and large boil-like skin lesions.

The virus gained international prominence in May 2022, when a less deadly strain called clade 2b spread around the world, mostly affecting gay and bisexual men.

Between January 2022 and June 2024, 208 deaths and more than 99,000 mpoxcases were recorded across 116 countries, according to the WHO.

What is new?

The latest surge has been of the deadlier clade 1—and its new mutated variant. 

The new strain, called clade 1b, was first detected among sex workers in the DRC in September 2023.

Sweden earlier reported the first case of the variant outside of Africa, and the EU's health body urged countries to increase preparedness. Pakistan reported Asia's first case.

"It is not surprising... that travel between continents has brought this case to Europe," said Brian Ferguson, an Associate Professor of Immunology, University of Cambridge. 

He added that cases were likely to spike in Europe and elsewhere as "there are currently no mechanisms in place to stop imported cases of mpox."

Containing the epidemic will require "rapid international co-operation," said Francois Balloux of the University College of London Genetics Institute—adding there was "no evidence of transmission in Europe at this stage."

Who are affected?

Clade 1 mpox is "known for causing more severe disease in young children, pregnant women, and immunocompromised people," said Jonas Albarnaz, who specializes in pox viruses at the Pirbright Institute in Britain.

Clade 1b is driven by sexual transmission and mostly infects young adults, Albarnaz said.

It has also been recorded spreading through non-sexual contact between people, including children playing together at school.

Clade 1b causes death in around 3.6% of cases, though infants and children are more at risk, according to the WHO.

More mpox cases were reported in the first half of this year than in all of 2023, according to WHO figures.

The majority of recent cases have been in the DRC, where 548 people have died so far this year, the government said.

Over the last month, previously unaffected countries such as Burundi, Kenya, Rwanda, and Uganda have reported outbreaks, according to the Africa CDC. None have reported deaths, the WHO said.