Genetic analyses of clade 1b, first detected in September 2023 in Kamituga, DRC, show that this variant has since undergone mutations making it more easily transmissible between humans. Scientists have identified three new subvariants, one of which has spread beyond Kamituga to other cities in the DRC, neighbouring countries, and even internationally to e.g. Sweden and Thailand. The new data may also suggest that clade 1b entails a high risk of miscarriage.
This new research has been published as an accelerated scientific publication in the esteemed journal Nature Medicine.
Originally, mpox was considered a zoonotic disease that primarily spread from animals to humans. However, in 2022, the world witnessed an outbreak primarily affecting men who have sex with men. The new clade 1b differs as both men and women are now contracting the virus. Additionally, an increasing number of infections are being reported among healthcare workers and children.
"It's somewhat like SARS-CoV-2 – the virus undergoes mutations as it spreads. For clade 1b, we see that one particular subvariant appears to have become better at transmitting between humans, and it has now been detected in several countries outside East Africa. In addition, the number of infected pregnant women who miscarry is high among those we have tested," says Professor Frank Møller Aarestrup from DTU National Food Institute, who leads the GREAT-LIFE project
The GREAT-LIFE project is behind both the discovery of clade 1b and the development of a new PCR test, which enables the detection of clade 1b—undetectable by the original mpox tests.
