In coronavirus's alphabet soup of names, why Mu is 'variant of interest'

This week the World Health Organization named a new “variant of interest” of the coronavirus, called the Mu variant. It was first found in Colombia in January 2021, and has been found in about 39 countries so far.

Mu has changes, called mutations, which mean it might be able to evade some of the protection we get from COVID vaccines.

But one reassuring element is that, despite being around since January 2021, it doesn’t seem to be outcompeting Delta, the dominant variant across most of the world.

If Mu was truly a really bad variant, we would have expected to