According to the B.C. Centre for Disease Control, 46 cases of the new MU variant of COVID-19 have been detected in the province.
The information comes from the province’s whole genome sequencing data, which shows that the number of Mu cases has gone up 4.5 per cent, or by four cases, from the week of Aug. 22–28 to Aug. 29–Sept 4.
Mu is currently classified as a variant of interest, not of concern like the delta variant. Also known as B.1.621, the World Health Organization said the variant was first discovered in Colombia in January 2021.
In an update from WHO, infectious disease epidemiologist Maria Van Kerkhove said that mu was designated a variant of interest on Aug. 30 because some South American countries are seeing the proportion of Mu cases increase.
“But in other countries, the proportion of Mu is decreasing,” Van Kerkhove said. “Where Delta is, Delta takes over really quickly.”
Dr. John O’Horo, a Mayo Clinic infectious diseases physician, said that despite the emergence of Mu, Delta continues to be the dominant strain of the virus in the U.S. and elsewhere. This includes B.C., where the BC CDC said that Delta continues to make up 99 per cent of cases.
O’Horo said that the concern with new variants is vaccine effectiveness.
“The further that these change from the original, the more concern there is that it may evade some of the immune systems around that spike protein,” he said. “We can still see with the delta variant that vaccines are still able to connect with this and neutralize this at a high enough level to prevent hospitalizations and severe infections. As we look at things like the mu variant, the concern and the question that’s still unanswered is how much have these drifted in.”