Mpox Makes a Comeback: New Strain Emerges in Sweden, Raising Concerns

The global health community is on high alert once again as Sweden reports its first case of clade 1 mpox, a more severe strain of the virus previously confined to Africa. This development comes on the heels of the World Health Organization’s (WHO) declaration of the mpox outbreak in Africa as a global health emergency. While the recent global outbreak of mpox, primarily caused by clade 2, subsided in 2023, the emergence of clade 1 in Europe signals a potential shift in the virus’s trajectory.

Clade 1: A Cause for Concern

Unlike clade 2, which characterized the global outbreak from 2022 to 2023, clade 1 mpox is known for its higher mortality rate. Data from the African CDC highlights the stark difference: the case fatality rate for clade 1 mpox can be as high as 10%, compared to less than 1% for clade 2. This higher mortality rate, coupled with the lack of widespread immunity against clade 1, makes this strain particularly concerning.

The Swedish Case: A Wake-Up Call

The discovery of clade 1 mpox in Sweden underscores the need for continued vigilance and proactive measures to prevent further spread. The individual infected in Sweden had recently traveled to Africa, raising concerns about potential travel-related transmission. The case highlights the importance of robust surveillance systems and timely identification of imported cases to prevent local outbreaks.

Understanding the Risks: Clade 1 vs. Clade 2

It’s crucial to differentiate between the two clades of mpox:

• Clade 2: This strain was responsible for the recent global outbreak, primarily impacting individuals who identified as gay, bisexual, or other men who have sex with men (MSM). This clade is characterized by milder symptoms and a lower mortality rate.

• Clade 1: This strain is prevalent in Central and West Africa and has a higher fatality rate. It can be transmitted through close contact with infected animals, infected individuals, or contaminated materials. Symptoms can be severe, including fever, headache, muscle aches, and a rash.

A Global Response: Lessons Learned and Next Steps

The emergence of clade 1 mpox in Sweden serves as a reminder that the battle against this virus is far from over. The global response needs to be strengthened and adapted to the changing landscape of mpox. Here’s a breakdown of critical next steps:

• Enhanced Surveillance: Global surveillance systems need to be strengthened to detect and track emerging mpox cases, including those related to different clades. This includes increased testing and reporting, particularly in areas with travel links to Africa.

• Improved Vaccination Strategies: While the current vaccines, designed primarily against clade 2 mpox, offer some protection against clade 1, further research and development are needed to ensure more effective and widespread vaccination coverage.

• Public Health Education: Public health education campaigns are crucial to raise awareness about mpox, including the different clades and their risks. This education should emphasize preventive measures such as safe sex practices and avoiding contact with infected animals.

• International Collaboration: Effective control of mpox requires strong collaboration between countries. The sharing of information, resources, and research findings is crucial to ensure a coordinated global response.

Moving Forward: A Collective Effort

The emergence of clade 1 mpox in Sweden serves as a wake-up call, reminding us that the threat of mpox remains real. The global community needs to act swiftly and decisively to address this challenge. By strengthening surveillance systems, improving vaccination strategies, promoting public health education, and fostering international collaboration, we can mitigate the risks posed by this evolving virus. This is not a fight that any single country can win; it requires a collective effort to protect global health and prevent a resurgence of this potentially devastating disease.