Everything we know about the mu variant, the latest coronavirus mutation

On Monday the World Health Organization (WHO) officially labeled the mu variant as a 'variant of interest,' a designation that indicates a need for further study about possible dangers while falling short of the more serious classification, 'variant of concern.' Variants of concern are regarded as a top priority because they are more immunity-resistant, contagious or deadly than other strains. Currently the WHO considers four strains to meet those criteria: alpha, beta, gamma and delta (the variant most prevalent in the United States).