Global health authorities have confirmed the first case of a new strain of the mpox virus outside Africa, marking a concerning development in the ongoing outbreak. The case was detected in Sweden, where a traveler returning from Africa tested positive for the clade Ib strain of mpox. This strain has been linked to a rapidly spreading outbreak in Africa, prompting the World Health Organisation (WHO) to declare a global public health emergency.

Swedish health officials disclosed that the infected individual contracted the virus while in Africa and is currently receiving treatment. The clade Ib strain involved in this case is a variant of clade I, which is endemic to the Democratic Republic of Congo (DRC). The virus appears to spread more easily through close contact, including sexual contact, raising concerns about its potential to cause a wider international outbreak.

“The emergence of a case on the European continent could spur rapid international spread of mpox,” warned Lawrence Gostin, a public health expert and professor at Georgetown Law in Washington. “A case in Sweden most likely means dozens of undetected cases in Europe.”

Dr. Brian Ferguson of the University of Cambridge echoed these concerns, noting that the case in Sweden was alarming but not unexpected given the severity of the outbreak in Africa. “There will likely be more cases in Europe and other parts of the world as there are currently no mechanisms in place to stop imported cases of mpox from spreading,” he said.

The WHO’s declaration of the outbreak in Africa as a Public Health Emergency of International Concern (PHEIC) underscores the seriousness of the situation. Since January 2023, the outbreak in the DRC has led to 27,000 reported cases and over 1,100 deaths, predominantly among children. The virus has since spread to neighboring countries, further exacerbating the crisis.

In response to the escalating situation, the global vaccine alliance Gavi has allocated up to $500 million to procure vaccines for countries affected by the mpox outbreak in Africa. The United States and Canada have so far not reported any cases of the clade Ib strain, but public health agencies are closely monitoring the situation.

The U.S. Centers for Disease Control and Prevention (CDC) has issued an updated Health Alert Network advisory and a Travel Health Notice to inform clinicians, travelers, and public health partners about the spread of the virus to regions that have not previously reported mpox cases.

According to U.S. health officials, Clade I mpox is associated with a greater number of severe infections and a higher mortality rate compared to Clade II. In 2022, the WHO declared a public health emergency in response to an outbreak of mpox caused by Clade II, which resulted in over 95,000 cases across 115 non-endemic countries.

As global health officials work to contain the outbreak, the confirmation of the first mpox case in Europe underscores the urgent need for coordinated international efforts to prevent further spread of the virus.