4 ms·

"That puts a ceiling on pre-existing immunity at somewhere around 40%." No, you're assuming that pre-existing immunity excludes people testing positive for the

by timr 6y ago

"That puts a ceiling on pre-existing immunity at somewhere around 40%." No, you're assuming that pre-existing immunity excludes people testing positive for the virus. You can test positive while mounting a robust immune response. In fact given that most infections are minimally symptomatic, it's arguable that immunity is the norm, not the exception.

michaelmrose 6y ago
That isn't what the word immunity means.
- timr 6y ago
  I'm not sure what you're trying to argue, but an immune response in no way precludes testing positive for a virus. Particularly at the testing thresholds we are using in the US, where as little as a single copy of the virus RNA can be detected, a great number of people test positive for weeks after their immune system has defeated the virus.
- sa1 6y ago
  He may not be wrong. T-cells are not like antibodies, which is the immunity you are thinking of.
- cblades 6y ago
  What the words means in common usage doesn't have to track what immunity actually is. Colloquially, immunity means sterilizing immunity. Actually, immunity doesn't have to be sterilizing.
nradov 6y ago
You shouldn't be downvoted. Immunity is a spectrum, not a binary condition. If the pre-existing immunity hypothesis is correct then it probably doesn't provide complete protection in all cases. It might cause some patient to experience asymptomatic or paucisymptomatic infections instead of full blown clinical COVID-19. Those patients can still test positive. The CDC estimates that 40% of infections are asymptomatic. https://www.cdc.gov/coronavirus/2019-ncov/hcp/planning-scenarios.html https://www.cdc.gov/coronavirus/2019-ncov/hcp/planning-scena...
- timr 6y ago
  Yes, this is exactly correct. And there's some reason to believe that the most severe cases are the result of an overactive immune response (though I haven't kept up with research into this hypothesis, so don't take my word for it). I don't tend to place a lot of emphasis on downvotes on this topic. I have a background in this area, so I know when I'm on solid ground, and there are a lot of people who simply don't want to accept the prevalence of asymptomatic infection, even today. More generally, nuanced opinions about this virus are targets for attack from both sides of the political spectrum. It's a tough time to be a scientist.

by timr 6y ago

michaelmrose 6y ago

That isn't what the word immunity means.

timr 6y ago
I'm not sure what you're trying to argue, but an immune response in no way precludes testing positive for a virus. Particularly at the testing thresholds we are using in the US, where as little as a single copy of the virus RNA can be detected, a great number of people test positive for weeks after their immune system has defeated the virus.
sa1 6y ago
He may not be wrong. T-cells are not like antibodies, which is the immunity you are thinking of.
cblades 6y ago
What the words means in common usage doesn't have to track what immunity actually is. Colloquially, immunity means sterilizing immunity. Actually, immunity doesn't have to be sterilizing.

nradov 6y ago

You shouldn't be downvoted. Immunity is a spectrum, not a binary condition. If the pre-existing immunity hypothesis is correct then it probably doesn't provide complete protection in all cases. It might cause some patient to experience asymptomatic or paucisymptomatic infections instead of full blown clinical COVID-19. Those patients can still test positive. The CDC estimates that 40% of infections are asymptomatic. https://www.cdc.gov/coronavirus/2019-ncov/hcp/planning-scenarios.html https://www.cdc.gov/coronavirus/2019-ncov/hcp/planning-scena...

timr 6y ago
Yes, this is exactly correct. And there's some reason to believe that the most severe cases are the result of an overactive immune response (though I haven't kept up with research into this hypothesis, so don't take my word for it). I don't tend to place a lot of emphasis on downvotes on this topic. I have a background in this area, so I know when I'm on solid ground, and there are a lot of people who simply don't want to accept the prevalence of asymptomatic infection, even today. More generally, nuanced opinions about this virus are targets for attack from both sides of the political spectrum. It's a tough time to be a scientist.