Variety

Even people not exposed to Covid-19 may have pre-existing immunity: Study

Prashasti Awasthi Mumbai | Updated on August 10, 2020 Published on August 10, 2020

According to a study published in Nature Reviews Immunology, people unexposed to Covid-19 may have some pre-existing immunity against the virus. However, the source and clinical relevance of the reactivity remains unknown.

The study, ‘Pre-existing immunity to SARS-CoV-2: the knowns and unknowns’, noted that people have some T-cell reactivity against SARS-CoV-2. The researchers said that it is important to define the specifics of these T-cells and assess their association with Covid-19 disease severity and vaccine responses.

According to the findings, lymphocytes, a subtype of a white blood cell in a vertebrate’s immune system, from 20-50 per cent of unexposed donors display significant reactivity to SARS-CoV-2 antigen peptide pools.

The study highlighted that pre-existing T-cell immunity to SARS-CoV-2 could be relevant because it could influence Covid-19 disease severity.

It is plausible that people with a high level of pre-existing memory CD4+ T cells that recognise SARS-CoV-2 could mount a stronger immune response upon exposure to SARS-CoV-2 and thereby limit disease severity.

The study mentioned that memory CD4+ and CD8+ T cells might also facilitate direct antiviral immunity in the lungs and nasopharynx early after exposure of the coronavirus.

Pre-existing CD4+ T-cell memory could also influence vaccination outcomes, leading to a faster or better immune response, particularly the development of neutralising antibodies, which generally depend on T-cell help.

Follow us on Telegram, Facebook, Twitter, Instagram, YouTube and Linkedin. You can also download our Android App or IOS App.

Published on August 10, 2020
This article is closed for comments.
Please Email the Editor