The original Covid-19 variant was deliberately sprayed into the subjects’ noses, then nasal and blood samples and tests were taken regularly for 28 days.
– Six people tested positive in both daily tests for more than two days, while showing symptoms. – Three others tested positive in one of the two daily tests, but not the other, for up to two days, without showing symptoms. – Finally, seven people systematically tested negative for the virus, and it is of course especially them who interest researchers.
What did we discover?
That patients who never showed symptoms and those who never tested positive the subjects produced interferon, a substance that helps the immune system fight infections. In these patients, it is found in their blood before it is produced in their nasopharynx, where the nasal samples were taken. Another observation: no infection was observed in their immune T cells and macrophage cells.
Finally, the results show that these patients had high levels of activity of an immune system gene called “HLA-DQA2,” which helped prevent lasting infection.
What are the repercussions after this discovery?
This unique investigation provides a better understanding of the cellular responses associated with protection against Covid-19, which could contribute to the development of new vaccines and treatments. But the investigation also has limits, the scientists point out, because in an epidemic context, we are exposed to several variants and not just the original variant as in this study.
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