Originally Posted by James Lacey
TL;DR: Exposure to common colds might give some people a head-start on immunity to COVID-19
Paper published August 4th; widespread reporting just showing up now.
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.
"Exposure to common colds might give some people a head-start on immunity to COVID-19" I sure hope this is the case. I have heard this suggested in a couple of places recently, and it might go a ways toward supporting early herd-ish immunity as an explanation for the infection graphs that seem to be repeating in each state. As I mentioned to old Dodgeball in the other thread, I remain optimistic for the fall.
I am reasonably confident based upon plenty of reading that the level of early herd-ish immunity correlates with the social mitigation level. So, to the extent folks give up on SD, masks and the like, I expect larger second waves even though some portion of the population might have some resistance to the disease imparted by common cold T-cells. Colorado has experienced this in a fairly manageable setting. Some of this is a necessary evil, since I do not support wholesale economic shut down, even though I think it is stupid not to do the easy SD/masks/work from home stuff.
Jim