Variants of Concern SARS-CoV-2

Authors: Andrianarison M; Raharolahy O; Sendrasoa FA; Ranaivo IM; Ramarozatovo LS; Rapelanoro Rabenja F – University of Antananarivo, Madagascar

Event: 10th Annual Conference of ANAMEM-SOMADER (August 2021) (Academy of Medicine of Madagascar and Malgasy Society of Dermatology)

  • A variant is defined by a change that a virus undergoes during its propagation, this change is made by mutation and this can influence the rate of transmission and virulence of the virus, and can have an impact on the severity of the disease.
  • The delta variant is characterized by the protein mutations T19R, DEL157-158, L452R, T478K, D614G, P681R and D950N.1. This can affect the immune responses of the receptor binding protein (452 ​​and 478). Furthermore, the P681R protein is on the S1-S2 cleavage site, the mutated strains associated with this site can lead to replication inducing more virulence and increased transmission.
  • Currently, there are 5 things already known and admitted by the literature concerning the delta variant.
    • First, the virus spreads very quickly around the world.
    • the virus is very contagious and causes more serious clinical forms, most often requiring hospitalization.
    • However, two doses of the vaccine have been shown to be effective in preventing the Delta variant and severe forms. The delta variant virus is a very cosmopolitan virus and spreads rapidly around the world.
    • Its virulence induces serious forms which imperatively require hospitalization, it affects adults as well as children, hence the importance of reiterating the maintenance of barrier gestures, especially for those whose vaccine is still inaccessible such as children.
    • Otherwise, two doses of vaccine are needed to effectively control the delta variant.


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