People recovered from COVID get immunity for 8 months, vaccines may extend duration: Study

According to a new study published in journal Science Immulogy, conducted by Australian scientists from Monash Univeristy, it was revealed that people who have recovered from vel coronavirus infection have an immune memory to protect mselves from reinfection for as long as 8 months. study said that re are specific cells in immune system, called ‘B’ cells, which when re-exposed to virus, leads to a protective immune response through rapid production of protective antibodies. 25 COVID-19 patients participated in study. Also, 36 blood samples were taken from m, beginning from Day 4 of infection to day 242.

Immunity for 8 months 

It was n concluded that antibodies against virus started to come off after 20 days of infection. However, this is when memory B cells work as y remember few characteristics of virus. Using which, spike protein helps virus enter host cells. “ antigen-specific B cell response to SARS-CoV-2 was characterized using recombinant forms of RBD and NCP. Both proteins were generated in Expi293F cells with an AviTag for targeted biotinylation and tetramerization with fluorescently-labeled streptavidins to minimize epitope masking”, said study. 

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(Construct design and detection of SARS-CoV-2 RBD- and NCP-specific B cells. (A) Recombinant spike receptor binding domain (RBD) and nucleocapsid protein (NCP) constructs of SARS-CoV-2. (B) SDS P of purified, reduced (R) or n-reduced (NR) recombinant RBD and NCP. (C) Flow cytometry stainings of CD19+ B cells from an uninfected control and a recovered COVID-19 patient using double discrimination through inclusion of two fluorescent tetramers for each protein (RBD or NCP) in same staining tube. Im Credits: immulogysciencemag.org)

(Neutralizing antibodies and RBD-, and NCP- and HA-specific IgG antibody levels. Credits: immulogysciencemag.org)

( RBD- and NCP-specific Bmem cells predominantly express IgM or IgG1. Im Credits: immulogysciencemag.org)

( Composition and kinetics of SARS-CoV-2 RBD- and NCP-specific Bmem in convalescence. Relative composition of Bmem cell compartment based on Ig isotype and IgG subclass expression within (A) RBD-specific (RBD+) and (B) NCP-specific (NCP+) Bmem subsets. Patients’ data are ordered by days post-symptom onset. Absolute numbers of total, IgM+and IgG+ Bmem cells specific for (C) RBD+ or (D) NCP+. Im Credits: Immulogy.science.org)

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Study co-author, Men van Zelm, from Monash University Department of Immulogy and Pathology, said, “se results are important because y show, definitively, that patients infected with COVID-19 virus do in fact retain immunity against virus and disease. This has been a black cloud hanging over potential protection that could be provided by any COVID-19 vaccine and gives real hope that, once a vaccine or vaccines are developed, y will provide long-term protection”. It was concluded that se virus-specific memory B cells were present for a period of eight months after infection.

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(Im Credits: Pixabay)