More than 4 years after the start of the Covid-19 pandemic, new variants continue to spread in France.
The initial strain of SARS-CoV-2 appeared at the end 2019 and which has since spread throughout the world mute regularly. After the Alpha, Delta variants… it is Omicron which has established itself in the world since the end of 2021. Several sub-lines of Omicron have followed one another (XBB, Pirola, Eris). “All share its characteristics: high transmissibility, immune escape and less severity compared to previous variants” noted Public Health France in the analysis of variants of June 2024. As of this date, there are no longer any variants classified as “concerning” but lineages under surveillance.
What is a variant?
All viruses, including Sars-CoV-2, evolve over time and mutate. The mutation potential of viruses increases with the frequency of infections (human and animal). Most mutations go unnoticed and do not change the effects of the virus. It may even be less contagious. The emergence of new variants of viruses is therefore not unexpected by scientists but they are worrying because they give the virus a increase in its transmissibility or a ability to evade the host immune responseexplained theECDC in a document published on December 29, 2020. These new strains or “variants” are then analyzed and closely monitored.
What is the majority variant in France at the moment?
An increase in Covid indicators has been observed since mid-May 2024, but it remains low compared to previous years. The variant which is majority in June is JN.1 (this has been the case since the end of November 2023). This variant represents, with all its sub-lineages, 55% of the interpretable sequences. The most detected JN1 sublineage is the KP2 and its circulation “seems to be accelerating.” He “raises questions due to its spread in certain countries and its genetic profile which may affect its characteristics”. The sublineage KP.3, which is progressing in the United States, has been detected in France since mid-April “but circulates at low levels”. The other variants detected are unclassified. The share of this category is decreasing and it is mainly represented by recombinant XDK (recombinant between JN.1.1.1 and XBB.1.16.11) which represented 12% of the sequences at the end of May.
What is the majority variant in the world?
Since the beginning of December 2023, the JN.1 variant (sublineage of BA.2.86) is the most detected lineage in the world with more than 80% of the sequences analyzed, informed Santé Publique France in June 2024. Within JN. 1, the KP.2 and KP.3 sublineages continue to increase since the beginning of March (around 20% of the sequences). Conversely, other JN1 sublineages are decreasing. Recombinants XBB (XBB.1.5, XBB.1.16, XBB.1.9, XBB.2.3 or even EG.5), which circulated widely in 2023, are now detected sporadically around the world.
What is the list of Covid variants?
Definition and classification of VOC, VOI, VUM variants
On March 15, 2023, theWHO has modified the organization of its classification in order to better reflect the international situation in terms of circulating variants. THE criteria by which a variant is classified as VUM, VOI or VOC have been updated :
► VUM = variant under investigation/under surveillance (variant under monitoring): genetic modifications with possible effect on its characteristics AND early signals of a growth advantage BUT uncertainties as to its epidemiological and clinical impact
► VOI: variant to follow (variant of interest): genetic modifications with possible or demonstrated effect on its characteristics AND growth advantage in more than one WHO region associated with an increase in the number of cases, or other epidemiological signal suggesting an increased risk to public health
► VOC: variant of concern (variant of concern): variant meeting the definition of a VOI AND increased severity OR significant reduction in vaccine effectiveness against severe forms OR modification of characteristics that may affect the capacity of healthcare structures to care for COVID- patients 19.
How are the names of Covid variants given?
On May 31, 2021, WHO decided to rename the main variants of Covid with greek letters (i.e. Alpha, Beta, Gamma…) in order to facilitate their pronunciation, to remember them more easily and also to avoid their association “stigma and discrimination” with the countries where they emerged (as the “English” variant was called, the “Indian” variant…), explained the authority in a communicated. These new names will not replace existing scientific names (for example those allocated by GISAID, Nextstrain and Pango), which convey important scientific information and will continue to be used in research (like B.1.1.7 for the so-called “English” variant). L’Greek alphabet has 24 letters.
| Letter number | Names of letters in the Greek alphabet (in bold the names used for Covid variants) |
|---|---|
| 1 | Alpha |
| 2 | Beta |
| 3 | Gamma |
| 4 | Delta |
| 5 | Epsilon |
| 6 | Zeta |
| 7 | eta |
| 8 | Theta |
| 9 | Iota |
| 10 | Kappa |
| 11 | Lambda |
| 12 | Mu |
| 13 | Naked |
| 14 | KSI/Xi |
| 15 | Omicron |
| 16 | Pi |
| 17 | Rho |
| 18 | Sigma |
| 19 | tau |
| 20 | Upsilon |
| 21 | Phi |
| 22 | Chi/Chi |
| 23 | Psy |
| 24 | Omega |
► Complete list of names of all Covid variants
How contagious are Covid variants?
“The circulating sub-lineages of the Omicron variant remain characterized by less severe clinical formsbut this lesser severity is partly linked to a preserved vaccine effectiveness against serious forms” specifies Public Health France.
| Alpha Variant | Beta Variant | Brazilian variant Gamma | Delta variant | Omicron variant |
|---|---|---|---|---|
| +29% compared to the initial strain of Sars-Cov-2 | +25% compared to the initial strain of Sars-Cov-2 | +38% compared to the initial strain of Sars-Cov-2 | +97% compared to the initial strain of Sars-Cov-2 | +30% compared to the Delta variant |