The case recorded in a traveller in Sweden was announced the day after the World Health Organization declared the mpox surge in Africa a public health emergency of international concern — the highest alarm it can sound.

The UN health agency was concerned by the rise in cases and fatalities in the Democratic Republic of Congo, and the spread to Burundi, Kenya, Rwanda and Uganda.

Sweden’s Public Health Agency told AFP on Thursday that it had registered a case of the Clade 1b subclade — the same new strain of the virus that has surged in the DRC since September 2023.

“A person who sought care” in Stockholm “has been diagnosed with mpox caused by the clade 1 variant. It is the first case caused by clade I to be diagnosed outside the African continent,” the agency said in a separate statement.

The person was infected during a visit to “the part of Africa where there is a major outbreak of mpox Clade 1”, state epidemiologist Magnus Gisslen said in the statement.

The agency added: “The fact that a patient with mpox is treated in the country does not affect the risk to the general population, a risk that the European Centre for Disease Prevention and Control (ECDC) currently considers very low.”

The WHO’s European regional office in Copenhagen said it was discussing with Sweden how best to manage the newly detected case.

“The confirmation of mpox Clade 1 in Sweden is a clear reflection of the interconnectedness of our world,” it said in a statement.

“There are likely to be further imported cases of Clade 1 in the European region over the coming days and weeks, and it is imperative that we don’t stigmatise travellers or countries/regions.”

“Travel restrictions and border closures don’t work and should be avoided,” it added.

548 deaths in DRC

The outbreak has centred on the DR Congo.

Health Minister Samuel-Roger Kamba said in a video message that the country “has recorded 15,664 potential cases and 548 deaths since the beginning of the year”, with all 26 provinces affected.

The DRC’s population is around 100 million.

He said the government had put in place a “national strategic plan for vaccination against mpox”, as well as improving surveillance of the disease at borders and checkpoints.

The minister said government-level working groups have been set up to boost contact tracing and help mobilise resources to “maintain control of this epidemic”.

Formerly called monkeypox, the virus was discovered in 1958 in Denmark, in monkeys kept for research.

It was first discovered in humans in 1970 in what is now the DRC.

Mpox is an infectious disease caused by a virus transmitted to humans by infected animals but can also be passed from human to human through close physical contact.

The disease causes fever, muscular aches and large boil-like skin lesions.

Vaccine drive

The US Department of Health said Wednesday it would be “donating 50,000 doses of the Food and Drug Administration (FDA)-approved JYNNEOS vaccine to DRC”.

“Vaccination will be a critical element of the response to this outbreak,” it said in a statement.

And Danish drugmaker Bavarian Nordic said it was ready to produce up to 10 million doses of its vaccine targeting mpox by 2025.

There are two subtypes of the virus: the more virulent and deadlier Clade 1, endemic in the Congo Basin in central Africa; and Clade 2, endemic in West Africa.

In May 2022, mpox infections surged worldwide, mostly affecting gay and bisexual men, due to the Clade 2b subclade.

The WHO declared a public health emergency which lasted from July 2022 to May 2023.

That outbreak, which has now largely subsided, caused some 140 deaths out of around 90,000 cases.

The Clade 1b subclade causes more severe disease than Clade 2b, with a higher fatality rate.