First identified in Colombia in January, the Mu variant of the coronavirus is “of potential concern,” but there is no data yet to suggest that it may overtake the Delta variant as a dominant strain, the European Medicines Agency (EMA), this Thursday.
The variant – B.1.621 according to scientific nomenclature – was classified as “variant to be monitored” by the WHO at the beginning of September.
Potential vaccine resistance
The European Medicines Agency (EMA) focuses primarily on the Delta variant, but “is also monitoring other variants that may spread, such as Lambda (identified in Peru) and more recently Mu,” said Marco Cavaleri, responsible for vaccine strategy. The variant “Mu could be potentially more worrying because it could show a potential risk of immune escape (resistance to vaccines)”, he specified at a press conference.
EMA will discuss with vaccine developers the efficacy of sera against the Mu variant. “But we don’t have data showing that the Mu variant is spreading so much or that there is a chance that it will overtake the Delta variant as the dominant strain,” he said, however. All viruses, including the SARS-CoV-2 responsible for Covid-19, mutate over time. Most mutations have little or no effect on the properties of the virus.
Four worrisome variants
However, certain mutations can affect the properties of the virus and influence, for example, how easily it spreads, the severity of the disease it causes, or the effectiveness of vaccines, drugs, diagnostic tools or other social and public health measures. The appearance, at the end of 2020, of variants that presented an increased risk to global public health led the World Health Organization to characterize variants to be monitored and variants of concern, in order to prioritize surveillance and research activities. global level.
Currently, the WHO considers that four variants are of concern, including the Alpha variants, present in 193 countries, and Delta, present in 170 countries, while five other variants are to be monitored (including Mu). First detected in Colombia in January, the Mu variant has since been reported in other South American countries and in Europe. The global prevalence of the Mu variant among sequenced cases was less than 0.1% in early September, “but its prevalence in Colombia (39%) and Ecuador (13%) has steadily increased,” according to the WHO.