A new Covid variant is being kept under surveillance by the World Health Organization (WHO) as its emergence has led to an increase in infections in several regions of the world. First identified at the end of January, the variant—called NB.1.8.1 but known informally as “Nimbus”—is a descendant of the Omicron family of Covid sublineages, and has become increasingly prevalent throughout the spring in Europe, the Americas, and the Western Pacific.
The virus has mutations that may increase its infectiousness and allow it to escape certain antibodies. Nevertheless, “considering the available evidence, the additional public health risk posed by NB.1.8.1 is evaluated as low at the global level,” the WHO