A deadlier strain of the mpox virus has been spreading in the Democratic Republic of the Congo, causing concern among experts that it could become a global threat if it spreads beyond Africa. The Centers for Disease Control and Prevention (CDC) has called for urgent global action to contain the virus, which has been detected in two genetically distinct groups called clades. The Clade I virus in the DRC has caused more severe illness and higher death rates compared to the Clade II virus that caused a global outbreak in 2022.
Since 2023, the DRC has reported a significant increase in suspected cases of the Clade I virus, prompting fears that it could spread to other countries. The virus has primarily been transmitted through interactions with infected animals and close contact with infected individuals. Evidence suggests that Clade I is now being spread primarily among adults through sexual contact. While most suspected cases of Clade I in the DRC are in children under 15, children in the U.S. are less likely to become infected due to better living conditions and access to hygiene resources.
A Canadian-led research team has discovered a new form of the virus, called the Clade Ib strain, with mutations that allow it to spread more efficiently among humans. Researchers have called for swift action from international health organizations to prevent another global mpox outbreak. Genetic analysis indicates that the mutated virus began spreading in the DRC in September. Another study found that countries affected by the Clade Ib virus do not have tests that can accurately detect the strain, leading clinicians to diagnose cases based on symptoms alone.
Both clades of the mpox virus have caused sporadic outbreaks in Africa for decades, with limited cases reported outside the continent. The virus is a relative of smallpox and has similar symptoms, including fever, swollen lymph nodes, and rash. While most cases are not severe, the Clade IIb strain that spread during the 2022 outbreak resulted in rashes and some health complications. Concern about mpox outbreaks in the U.S. lessened in recent decades before the 2022 outbreak, when thousands of mpox vaccines reportedly expired due to a perceived lack of threat.
In response to an uptick in Clade II virus cases in New York City, the Department of Health and Mental Hygiene issued a health advisory warning of increased cases since October. Most cases involved people who were not vaccinated or had only received one dose, with only a small number of hospitalizations reported. The CDC has recommended mpox shots for routine prevention among at-risk adults as more people become infected with the virus in the DRC. Experts are urging swift action to contain the spread of the virus and prevent a global outbreak.
