EYECARE: Coronavirus BRIEFING: Crisis Response Tactics Q&A: How Concerned Should We Be About the Mu Variant? By Staff Friday, September 10, 2021 9:03 AM Now that we're halfway through the Greek alphabet for naming coronavirus variants, it is clear that some are more worrisome than others. Only four so far have raised enough alarm to warrant a World Health Organization “variant of concern” designation–Alpha, Beta, Gamma, and Delta.But now there's a new one to add to the list: Mu, now categorized as a WHO “variant of interest.”Even though information and data on the variant, or B.1.621, is scarce, WebMD asked two experts in virology what it might have in store for us. Head over to WebMD to read the full story.