Mu or B.1.621, a new Covid-19 variant is being closely monitored by the World Health Organization (WHO). This comes after it showed signs of possible resistance to vaccines. It was first identified in Colombia in January 2021. It is now a variant of interest. Mu was added to the WHO’s watch list on August 30 after it was detected in 39 countries. Mu is the fifth variant of interest to be monitored by WHO since March. The variant has a number of mutations that suggest it could be more resistant to vaccines, the world health body warned. Watch the video to know more.