Q&A #09: Do cross-reactive T cells explain mild course of Omicron infection?

Q&A #09 with Geert Vanden Bossche

Question:

Do cross-reactive T cells explain mild course of Omicron infection as suggested by https://www.medrxiv.org/content/10.1101/2021.12.26.21268380v1?

Answer:

Note that this paper correctly states that “well-preserved T cell immunity to Omicron is likely to contribute to protection from severe COVID-19”. However, the data shown do not support the statement of these authors that “cross-reactive T cell responses acquired through vaccination or infection may contribute to these apparent milder outcomes for Omicron”. There is quite a difference between protection against symptomatic infection and protection from severe disease!

It will probably take some more time before scientists understand that cross-reactive CoV-specific T cells cannot explain the asymptomatic/ mild course of Omicron infection. CoV-specific T MEMORY cells do not provide sterilizing immunity and therefore cannot prevent or abrogate viral transmission. Of course, cytokines secreted by cross-reactive CoV-specific T cells could enhance recovery from disease and avoid a more severe course of C-19 illness. This is simply due to a T cell-mediated ‘adjuvant’ effect.

If in vivo priming of previously CoV-primed cross-reactive memory T cells were responsible for Omicron’s mild course of C-19 disease, one wonders why cross-reactive T memory cells were not already our bodies’ best shot at attenuating disease caused by the Delta variant. And how stupid would (vulnerable) people be to refresh their Flu shot on a yearly basis if cross-reactive T cells would be cross-protective against disease, or even infection. Some pretend, indeed, that vaccine-induced T cell immunity enables the immune system to limit the spread of the virus due to cross-reactivity of CoV-specific T memory cells! If this were to apply, we would expect a similar mechanism to occur in case of Flu vaccines, thereby making yearly vaccination with updated Flu shots completely redundant!

I can only insist that people read the rationale for the statements made above as explained in my recent contribution on this topic: https://www.voiceforscienceandsolidarity.org/scientific-blog/when-anti-s-pike-antibodies-against-omicron-can-no-longer-sustain-the-narrative-why-not-resort-to-t-cells.

And there is more: Fighting a viral pandemic with vaccines that only mitigate symptoms is likely to promote immune escape, regardless the immune mechanisms and the underlying effectors that are responsible for this mitigation...

More Q&A on: www.voiceforsciencenandsolidarity.org

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