Lambda variant

This is a new strain of the COVID-19 virus appearing in the UK. It is thought to be twice as contagious as the Delta variant. And if you are wondering what happened to the other letters of the Greek alphabet, they were allocated to various variants of interest which did not turn out to be variants of concern. 

 Epsilon appeared in California and was initially alarming because it had a mechanism for evading antibodies, but it had low transmissibility and so lost out to the alpha variant.  The Zeta variant appeared in Rio de Janeiro and was initially a variant of interest until it was dropped from the list entirely.  Eta was first detected in the UK and Nigeria in December 2020.  It has some unusual features in its spike which makes it a variant under investigation. Theta was first identified in the Philippines and caused brief concern but then dropped out of sight.  Iota appeared in New York in November 2020 and is a variant of interest.

Kappa is another strain from India.

 And so we appear to jump from Delta to Lambda which originated in Peru and is sometimes called the Andean strain. It is being tracked to see if it has increased transmissibility or increased severity, in which case it will be a variant of concern.