All viruses, including SARS-CoV-2, which is responsible for Covid-19, mutate over time.
Certain mutations can affect the properties of the virus and affect its spread, severity, or the effectiveness of vaccines and drugs.
The appearance, at the end of 2020, of variants of SARS-CoV-2, led the WHO to characterize the mutations to be monitored and those deemed to be of concern, in order to prioritize surveillance activities.
In its latest bulletin, published on Wednesday, the WHO classified the new variant B.1.621, dubbed "Mu", as "variant to follow".
And the others ?
As if the coronavirus were not enough, the variants had to further complicate the epidemic situation.
These mutations can affect the properties of the virus and affect its spread, severity or the effectiveness of vaccines.
And since their appearance at the end of 2020, the World Health Organization (WHO) has set up monitoring to characterize and prioritize them.
After Alpha, Delta and Beta, it is the new variant of the coronavirus, B.1.621, baptized "Mu" and identified for the first time in Colombia in January, which was classified as "variant to follow" by the WHO this Wednesday.
And so he is not alone.
Which variants are of concern?
Are they all equally dangerous?
20 Minutes
takes stock.
Variants of Concern (VOC)
The Alpha variant, or B.1.1.7, first spotted in the UK in September 2020, was listed as a variant of concern (VOC) on December 18, 2020. It is currently present in 193 countries and represents 1% of confirmed cases sequenced in France.
Very present in France at the start of 2021, it was gradually replaced from the spring by the Delta variant.
The Beta variant, or B.1.351, first spotted in South Africa in May 2020 and listed as of concern on December 18, 2020, is currently present in 141 countries, but not in France.
The Delta variant, or B.1.617.2, first spotted in India in October 2020. It was listed as a variant to track (VOI) on April 4, 2021 and of concern on May 11, 2021. This variant is currently present. in 170 countries and represents 98% of confirmed cases sequenced in France, according to the latest survey by Public Health France.
Delta is 40% to 60% more transmissible than the Alpha variant, 60% than the Beta variant, 30% than the Gamma variant.
It also has an increased risk of developing a severe form of the disease.
The Gamma variant, or P.1, first spotted in Brazil in November 2020 and listed as of concern on January 11, 2021, is currently present in 91 countries, but not in France.
Variants of Interest (VOI)
The Eta variant, or B.1.525, first spotted in several countries in December 2020 and listed as a variant to follow (VOI) on March 17, 2021, is currently present in 72 countries.
The Iota variant, or B.1.526, first spotted in the United States in November 2020 and listed to follow (VOI) on March 24, 2021.
The Kappa variant, or B.1.617.1.
First spotted in India in October 2020, it was listed as to watch on April 4, 2021.
The Lambda variant, or C.37.
First identified in Peru in December 2020, and listed as to follow on June 14, 2021.
The Mu variant, or B.1.621, spotted for the first time in Colombia in January 2021 and listed as to follow on August 30, 2021. In its latest bulletin, the WHO clarified that Mu has mutations that could indicate a risk of 'Immune escape', or resistance to vaccines.
Variants under evaluation (Virus Under Monitoring - VUM)
WHO also counts ten variants under evaluation, or Virus Under Monitoring (VUM).
These mutations, which present "genetic modifications suspected of affecting the characteristics of the virus", may "pose a future risk without the evidence of phenotypic or epidemiological repercussions being clear at the present time", explains the WHO on its site.
She says they are subject to enhanced surveillance and repeated assessment pending further evidence.
Health
Coronavirus: "High probability" of new "possibly more dangerous" variants, alerts WHO
Health
Coronavirus: Why are there more and more variants?
Oms
Delta variant
Coronavirus
Covid 19
Video
Health