According to the B.C. Centre for Disease Control’s latest weekly update on variants of concern and variants of interest (released on Friday for the week Aug. 29- Sept. 4) there has been 46 Mu cases detected since June, including two in the most recent week.
Prior to the World Health Organization’s declaration on Aug. 30 that the B.1.621 variant was a variant of interest and named Mu, the BCCDC had been keeping an eye on it through its whole genome sequencing system. In B.C. every positive test result is analyzed to see whether it is a variant of concern, a variant of interest or an emerging variant.
The highly contagious Delta variant of concern that has taken over the world now accounts for close to 100 per cent of all cases in B.C. Other VOCs – Gamma, Beta and Alpha – are now mostly non existent in the province.
While the Mu variant is in B.C. in relatively very low numbers, it’s worth keeping an eye on and here are some things to know.
Where did it come from?
Mu was identified in Colombia on Jan. 11, 2021, and has now been found in 31 countries.
It is the most recently recognized variant of interest, joining Eta (B.1.525), Iota (B.1.526), Kappa (B.1.617.1) and Lambda (C.37),
Colombia experienced a huge COVID-19 surge from March to August 2021 that peaked at 33,594 cases per day (on June 26, 2021).
Although the Gamma VOC was dominant in Colombia during the initial phase, the Mu VOI outcompeted all other variants including the Gamma VOC in May 2021 and has driven the epidemic in Colombia since then.
According to the WHO’s COVID-19 Bulletin published last week, Mu has caused some larger outbreaks in South America and Europe. While the number of genetic sequences identified as Mu have fallen below 0.1 per cent globally, it represents 39 per cent of variants sequenced in Colombia and 13 per cent in Ecuador, places where its prevalence has “consistently increased,” WHO reported.