Switzerland Sees Active Spread of New Mpox Variant Since Early 2026
Health officials in Switzerland have confirmed that a new strain of the mpox virus, known as Clade Ib, has been circulating actively in the country since January 2026. The emergence of this variant has raised concerns among public health experts, particularly given its distinct transmission patterns and the challenges it presents for prevention and control.
Since the start of the year, Swiss authorities have recorded 16 confirmed cases of mpox linked to Clade Ib. Unlike previous strains, this variant appears to spread more easily through close contact, including sexual transmission, which has prompted renewed discussions about protective measures and public awareness.
The World Health Organization (WHO) first declared mpox a Public Health Emergency of International Concern (PHEIC) in August 2024, citing a surge in cases in the Democratic Republic of Congo (DRC) and its spread to neighboring countries. The declaration highlighted the emergence of Clade Ib, a new and evolving strain of the virus, which has since been detected beyond Africa, including in Switzerland.
Mpox, formerly known as monkeypox, is not a new virus. It was first identified in humans in the 1970s, with rodents—not monkeys—serving as its natural reservoir. The disease has historically been endemic in parts of West, Central, and East Africa, but global cases surged in 2022, leading to increased vigilance and research. The discontinuation of smallpox vaccination programs in the 1980s has been linked to a rise in mpox cases, as the smallpox vaccine provided some cross-protection against the virus.
One of the key concerns with Clade Ib is its mode of transmission. While earlier strains of mpox primarily spread through direct skin-to-skin contact or exposure to contaminated materials, Clade Ib has shown a higher likelihood of sexual transmission. This shift has led health experts to emphasize that condom use alone may not be sufficient for protection, as the virus can spread through other forms of close contact. The European Centre for Disease Prevention and Control (ECDC) has assessed the overall risk to the general public in the EU/EEA as low, but the situation remains under close monitoring.
In Switzerland, health authorities are working to expand access to diagnostic testing, vaccines, and treatments to curb the spread of the virus. The WHO and its partners are also collaborating with affected countries to improve surveillance and response efforts, particularly in regions with limited healthcare resources. However, challenges persist, including a lack of comprehensive data on the transmissibility, severity, and case-fatality rates of the new strain.
The current outbreak underscores the ongoing need for global cooperation in addressing emerging infectious diseases. While mpox is generally considered a mild illness, its potential to spread rapidly—particularly in populations with limited immunity—highlights the importance of early detection and public health preparedness. For now, Swiss officials are urging individuals to remain vigilant, seek medical advice if symptoms appear, and follow recommended precautions to reduce the risk of transmission.
Symptoms of mpox typically include fever, headache, muscle aches, swollen lymph nodes, and a characteristic rash that may resemble pimples or blisters. The illness usually resolves on its own within a few weeks, but severe cases can occur, particularly in individuals with weakened immune systems.
As the situation evolves, health agencies continue to stress the importance of staying informed through reliable sources and adhering to public health guidelines. The emergence of Clade Ib serves as a reminder that infectious diseases can adapt and spread in unexpected ways, making ongoing research and international collaboration essential to protecting global health.
