BBM Mu quickly became the dominant strain in Colombia, where it was first detected in January, but in the U.S., where the Delta virus is dominant, it has not spread significantly. After reaching a peak at the end of June, the prevalence of the Mu variant in the U.S. has steadily declined. Scientists believe that the new variant cannot compete with the Delta variant, which is highly contagious. But a Variant of Interest, like Mu still raises worries. Mu has many known mutations that can help the virus escape immunity from vaccines or previous infection. ...... some clues are emerging that Mu can weaken protection from antibodies generated by existing vaccines. “[Mu] variant has a constellation of mutations that suggests that it would evade certain antibodies—not only monoclonal antibodies, but vaccine and convalescent serum-induced antibodies" Still, the good news is that Mu is unlikely to replace Delta in places like the U.S. where it is already predominant The Mu variant is on the rise. Scientists weigh in on how much to worry.