Sweden is the first country outside of Africa to report a case of mpox caused by the novel clade 1, the variant fueling a massive outbreak in the Democratic Republic of the Congo (DRC) and neighboring nations, while US officials report disappointing DRC trial results for a key drug—Tpoxx, or tecovirimat—against the more lethal strain.
Rwanda, Uganda, Burundi and Kenya, are the other African countries with clade 1b detections.
Swedish patient had recently visited Africa
According to a press release from the Public Health Agency of Sweden, the case-patient sought medical attention in Stockholm but had recently visited Africa. In 2022 and 2023, Sweden saw an outbreak of clade 2 cases linked primarily to sexual transmission among men who have sex with men, eventually recording about 300 cases.
This is the first clade 1 case identified in the country. The European Centre for Disease Prevention and Control said today it will soon update its risk assessment for the clade 1 mpox outbreak in Africa.
"This case does not require any additional infection control measures in itself, but we take the outbreak of clade I mpox very seriously," said Magnus Gisslen, MD, PhD, chief epidemiologist at the Public Health Agency of Sweden. "We are closely monitoring the outbreak and we are continuously assessing whether new measures are needed."
Case follows WHO declaration
The announcement of the Swedish case comes a day after the World Health Organization declared the outbreak in Africa a public health emergency of international concern (PHEIC).
The declaration comes 2 years after the WHO declared the global spread of clade 2 mpox cases a PHEIC, resulting in the widespread use of mpox vaccine in Europe and the United States to curtail the outbreak. Getting vaccine doses to Africa has proven more challenging; at least 10 million vaccine doses are needed for the current outbreaks in Africa, but so far only the DRC and Nigeria have taken the first regulatory steps to allow supplies to be used.
Yesterday Tim Nguyen, MPH, who heads the WHO's High Impact Events Preparedness unit, said there are about 500,000 doses of Bavarian Nordic's Jynneos vaccine available, with another 2.4 million doses that could be produced by the end of the year if there are orders. The company said it could produce another 10 million doses in 2025.
Several international scientists and public health experts weighed in today on the WHO PHEIC via the Science Media Centre.
"The situation is concerning because of the spread of the clade 1b virus, which is considered to cause more severe disease, and because there are many children being infected in DRC during this new outbreak," said Brian Ferguson, PhD, an associate professor of immunology at the University of Cambridge, said. "40% of cases are in children under 5 years old."
The situation is concerning because of the spread of the clade 1b virus, which is considered to cause more severe disease, and because there are many children being infected in DRC during this new outbreak.
Josie Golding, PhD, head of epidemics and epidemiology in Wellcome's Infectious Disease team, said, "We should not wait for diseases to escalate and cross borders before acting. Effective outbreak control requires sustained, coordinated efforts worldwide—from local and national governments, and public and private industry to funders, regulators and NGOs."
Jonas Albarnaz, a poxvirus researcher at the Pirbright Institute, added, "Little is known about the natural history and transmission dynamics of the new clade 1b variant, and this information is key to inform the control strategies."
Tpoxx did not reduce symptom duration
In a news release today, the US National Institutes of Health (NIH) said that, in a new trial, the antiviral drug Tpoxx did not reduce the duration of mpox lesions among children and adults with clade 1 mpox in the DRC, but it was safe.
"These findings are disappointing, but they give us essential information and reinforce the need to identify other therapeutic candidates for mpox while we continue research on tecovirimat use in other populations with mpox," said Jeanne Marrazzo, MD, MPH, director of the National Institute of Allergy and Infectious Diseases, which is part of the NIH. "We remain committed to developing safe and effective interventions, including treatments and vaccines, that can ease the devastating mpox burden in Central Africa and address the milder form of the virus that is circulating globally."
However, the case-fatality rate seen in the study was 1.7%—much lower than the 3.6% or higher reported in the DRC, which shows the benefit of good hospital care for case-patients. And Tpoxx maker Siga said the drug did provide benefit for those treated early, and those with severe disease (100 or more skin lesions). Early treatment was defined as within 7 days of symptoms.
"We believe these data warrant further investigation and support our view that post exposure prophylaxis will be vital for treatment of severe cases of mpox and all cases of smallpox," said Dennis Hruby, PhD, Siga’s chief scientific officer in a press release.
We believe these data warrant further investigation and support our view that post exposure prophylaxis will be vital for treatment of severe cases of mpox and all cases of smallpox
Since November of 2023, the DRC has reported more than 16,000 new mpox cases, as well as more than 500 deaths this year.
