3 ms·

when did transmissibility become a defining metric? There are more transmissible pathogens (colds, flu), but we don't change society for those. I was told that

when did transmissibility become a defining metric? There are more transmissible pathogens (colds, flu), but we don't change society for those. I was told that mortality was the defining metric (and thus the reason for the restrictions, to save lives), so if B.1.1.7 is less lethal, why would the transmissibility play in? Also why isn't immunization from natural infection counting? I've seen to reason to _discount_ it; it just seems they are looking for ways to juke the stats

rsynnott 5y ago
> so if B.1.1.7 is less lethal, why would the transmissibility play in? I mean, if it was a _lot_ less lethal, and became permanently dominant, then the problem goes away. I think your mistake is in assuming that it is less lethal. What gave you that idea? It is believed to probably be _more_ lethal. > Also why isn't immunization from natural infection counting? It 'counts', but less so than vaccine immunity, because some variants defeat it while not defeating most vaccines (there's some messiness at the edges here; for instance AZ may not work very well for the South African variant).
lamontcg 5y ago
> if B.1.1.7 is less lethal, why would the transmissibility play in? Transmissibility, viral load and virulence should all be correlated. Alizon, S., Hurford, A., Mideo, N. and Van Baalen, M. (2009). Virulence evolution and the trade-off hypothesis: history, current state of affairs and the future. Journal of Evolutionary Biology 22, 245–259. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1420-9101.2008.01658.x https://onlinelibrary.wiley.com/doi/full/10.1111/j.1420-9101... When you read stories that a particular variant increases one or two of those three and not the other, you should treat it skeptically. All three should tend to move together. B.1.1.7 is most likely more lethal, any studies contradicting that are probably not picking appropriate controls to compare against (e.g. the most vulnerable sub-populations of demographic slices having been already hit by old school D614G, so lethality appearing to fall no matter what).

rsynnott 5y ago

> so if B.1.1.7 is less lethal, why would the transmissibility play in? I mean, if it was a _lot_ less lethal, and became permanently dominant, then the problem goes away. I think your mistake is in assuming that it is less lethal. What gave you that idea? It is believed to probably be _more_ lethal. > Also why isn't immunization from natural infection counting? It 'counts', but less so than vaccine immunity, because some variants defeat it while not defeating most vaccines (there's some messiness at the edges here; for instance AZ may not work very well for the South African variant).

lamontcg 5y ago

> if B.1.1.7 is less lethal, why would the transmissibility play in? Transmissibility, viral load and virulence should all be correlated. Alizon, S., Hurford, A., Mideo, N. and Van Baalen, M. (2009). Virulence evolution and the trade-off hypothesis: history, current state of affairs and the future. Journal of Evolutionary Biology 22, 245–259. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1420-9101.2008.01658.x https://onlinelibrary.wiley.com/doi/full/10.1111/j.1420-9101... When you read stories that a particular variant increases one or two of those three and not the other, you should treat it skeptically. All three should tend to move together. B.1.1.7 is most likely more lethal, any studies contradicting that are probably not picking appropriate controls to compare against (e.g. the most vulnerable sub-populations of demographic slices having been already hit by old school D614G, so lethality appearing to fall no matter what).