2. The immune system can remember viruses. And there are multiple different parts of the immune system that can remember a virus in different ways, so the immune system can fight the virus in multiple ways.
3. Our data shows that the body’s immune system remembers novel coronavirus for at least 8 months after COVID-19, and multiple different branches of the immune system remember the virus.
4. This suggests that the immune system can remember the SARS-CoV-2 virus for years, and most people may be protected from severe COVID-19 for substantial time. Which is certainly good news!
5. For the aficionados, we found complex relationships between the different components of immune memory.
6. Which included a lack of predictive power of serum antibody titers for predicting the magnitude of the T cells.
7. These overall COVID-19 immune memory findings are consistent with multiple other labs, including @PepperMarion, Nussenzweig lab, and van Zelm lab, and the healthcare workers study finding no symptomatic re-infections over 6 months. medrxiv.org/content/10.110…
8. We first reported this work as a pre-print in November, as a 6 month study, which has been expanded to 8 months, and additional data.
1. I am convinced that the new "UK variant" of SARS-CoV-2 (B.1.1.7) is a big problem. I look forward to seeing more epidemiology by more labs (not my area), but the overall picture plus these new viral load data now have me convinced. (my PhD was RNA virology)
Thread
2. An analysis of 641 COVID-19 cases found "S-negative" (B.1.1.7 inferred) cases had 10 to 100-times higher nasal viral loads than 'regular' COVID-19. Virologically, that is a massive difference. It could easily explain higher transmissibility. doi.org/10.1101/2020.1…
3. The authors of that work are appropriately cautious in their interpretations (e.g. they didn't directly sequence confirm B.1.1.7 cases), and it will be very valuable to see similar studies from other sites. But, I find the data compelling.
Got lots of interest in my RNA vaccine explainer yesterday. The most common follow up questions generally fell into two categories, well stated in the tweet below. I will answer both. 1/5
First, to paraphrase: “Isn’t it strange for the immune system to deal with a viral protein from RNA in host cells?” Actually, the human immune system has spent millions of years evolving to recognize viruses this way. (Really, vertebrates have spent 500 million years doing this!)
Viruses regularly express their proteins on infected human cells, and the immune system specifically recognizes those foreign viral molecules. Indeed, many viruses are RNA viruses (they use RNA as their genetic material!), so the immune system is specifically good at this job.
1/ Are RNA vaccines safe? I have gotten this question a lot lately, and it is a good question.
2/ First: RNA is messages. At any moment a human cell has 5000+ different RNA messages, and they are all temporary messages, like post-it notes that get torn up by the cells within minutes or hours after being read.
3/ Or, actually, RNA is like snapchat messages that expire. RNA vaccines do NOT become a permanent part of your body. They are temporary messages instructing cells to make one viral protein temporarily.
1/ This paper is the first significant evidence that recent infection with a common cold coronavirus could have a functional cross protective effect against severe COVID-19. “Recent endemic coronavirus infection is associated with less severe COVID-19" jci.org/articles/view/…
2/ The possibility of pre-existing (partial) immunity to COVID-19 has been a hot topic. The presence of cross-reactive memory T cells in a fraction of the population opened the possibility of some degree of pre-existing immunity in the population. nature.com/articles/s4157…
3/ Cross-reactive T cells can provide some degree of protective immunity in flu (Sridhar et al., 2013; Wilkinson et al., 2012). The different ways in which such immunity may manifest for SARS-CoV-2 infection are discussed in: nature.com/articles/s4157…
1/ This is one of the most interesting pre-prints I have seen this past month. I consider this study in two parts. biorxiv.org/content/10.110…
2/ In the first part, Nussenzweig and colleagues show compelling data that memory B cells specific for RBD (the target of neutralizing antibodies against SARS2) undergo affinity maturation over time.
3/ They demonstrate this by cloning mAbs from the memory B cells, sequencing the B cells to show SHM, and characterizing the improved binding capacity of the mAbs.