Why some don't get COVID-19 or have mild symptoms.

[safeinOhio]

https://science.sciencemag.org/content/early/2020/08/04/science.abd3871


Abstract
Many unknowns exist about human immune responses to the SARS-CoV-2 virus. SARS-CoV-2 reactive CD4+ T cells have been reported in unexposed individuals, suggesting pre-existing cross-reactive T cell memory in 20-50% of people. However, the source of those T cells has been speculative. Using human blood samples derived before the SARS-CoV-2 virus was discovered in 2019, we mapped 142 T cell epitopes across the SARS-CoV-2 genome to facilitate precise interrogation of the SARS-CoV-2-specific CD4+ T cell repertoire. We demonstrate a range of pre-existing memory CD4+ T cells that are cross-reactive with comparable affinity to SARS-CoV-2 and the common cold coronaviruses HCoV-OC43, HCoV-229E, HCoV-NL63, or HCoV-HKU1. Thus, variegated T cell memory to coronaviruses that cause the common cold may underlie at least some of the extensive heterogeneity observed in COVID-19 disease.

[phylny]

1. I have a graduate degree and I can't understand a bit of this. n/t

[Baitball Blogger]

2. My guess: Some people have T-Cells that can help them fend off this coronavirus because

of previous exposure to common colds. But, no one knows why or where they got that exposure.

[phylny]

3. Thank you!

[Nay]

4. At the conclusion of the paper, the writers say that there is evidence that previous

exposure to certain specific cold viruses can stimulate a person's T-cells (cells that will 'remember' invading viruses and prompt a very quick bodily reaction to stop the invader) quickly enough that the person will have an asymptomatic response to COVID19 -- IOW, the virus gets beaten back before you get sick -- or the person will have only mild symptoms and then shake off the virus. They conclude by saying their results are still very speculative.

But I may be reading this incorrectly, so it's IMHO.

[safeinOhio]

5. I brought it up because

Dr. fauci referred to it yesterday.

[Nay]

6. I think it's probably true, but researchers haven't found the exact pathway that

goes from "existing cold germ immunity" to "T-cells that attack COVID too." If they can find out exactly what is happening in all those steps, there's a good chance that they'll be able to develop a vaccine or shot that will at least keep a case of COVID from killing you or damaging you severely. Let's hope!

[safeinOhio]

8. Thank you.

Trying to keep up. I now wear a shield along with a mask. Looking more like aerosol spray may be more dangerous than any other way of spreading the virus. That along with load and speed has me trying that combination to stay safe. Cant hurt.

[clarkd101]

9. Thanks

Thank you for the information.

[safeinOhio]

10. You are welcome and welcome to DU.

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