4 ms·

That’s exactly the point though! The real question is “what is the relative severity, conditioned on prior immunity” — as in, what is the intrinsic virulence.

by rsfern 5y ago

That’s exactly the point though! The real question is “what is the relative severity, conditioned on prior immunity” — as in, what is the intrinsic virulence. As in, should an unvaccinated person with no prior Covid expect delta symptoms, or this list? We apparently still can’t answer that with confidence given the data currently available to us, but it seems unlikely to me that this cohort should expect anything milder than the wild type. We can hope it is milder, and we’ll learn more soon.

unclebucknasty 5y ago
Yes, the data is still coming in so not 100% sure. But, unless I'm missing something, one benchmark would be the relative severity profile versus the outgoing Delta variant, right? I mean, it seems there would be no reason to expect a sudden change in severity from one virus to the next in such a short time span, unless there was something intrinsically different about this virus. EDIT: I'd add to that there also seems to be an overwhelming prevalence of those five seemingly milder symptoms versus symptoms from previous variants. There also would not have been a sudden surge in immunity that would explain such a rapid shift. Also, see ms to be not just milder symptoms, but different symptoms. So there does seem to be something intrinsically different here. Given all we've heard about the striking mutations at the spike proteins for Omicron, it's probably not surprising since they drive so much of the virus's profile.
- rsfern 5y ago
  > one benchmark would be the relative severity profile versus the outgoing Delta variant, right? Agreed, and that’s what this SA study is doing. They compare to delta cases from this summer, and also non-omicron (presumably mostly delta? I can’t tell) cases from this November. They find that cases are less severe than in the summer, but not enough data to conclude any difference compared to November non-omicron. More data will tell us if it’s intrinsically milder with different symptom profile, or if the other strains in November were not delta, or if it actually only seemed milder because of undercounting prior infections, or something else
  - unclebucknasty 5y ago
    I was multitasking on that last EDIT so probably not very clear. Sorry. >They compare to delta cases from this summer, and also non-omicron (presumably mostly delta? I can’t tell) cases from this November. From the article: Compared to delta infections in South Africa between April and November, omicron infections are associated with a 70% lower risk of severe disease, they said. The omicron data was collected for the two months through November. I read from that significant overlap in comparisons between both summer through November, as well as Omicron and Delta up through November. In all, that statement seems to specifically address most of your questions, as they have directly compared per the variables you seem to be questioning. The one thing they have not been able to conclude is the role immunity played in the differences. That's where I'm lobbing in my opinion (partially sourced from other reports, beyond this study) that we might be able to read into the seemingly stark shift when Omicron hit the scene, particularly WRT symptom variation. While we are awaiting more data, there does seem to be a consistency in these reports, and that consistency points to a sudden and observable difference in Omicron symptomology that would not be explained by increased immunity alone (again, my opinion, informed by the study time frames and other sources). Of course they can't conclude that yet, but I'm predicting that's what the data will show. So that was my internet layperson attempt to address your original question with regard to intrinsic virulence versus immunity. I just think it's unlikely that we're coincidentally seeing a sudden surge in immunity concomitant with the appearance of a new variant, which also happens to have a ton of mutations and starkly different spike profile.

by rsfern 5y ago

unclebucknasty 5y ago

Yes, the data is still coming in so not 100% sure. But, unless I'm missing something, one benchmark would be the relative severity profile versus the outgoing Delta variant, right? I mean, it seems there would be no reason to expect a sudden change in severity from one virus to the next in such a short time span, unless there was something intrinsically different about this virus. EDIT: I'd add to that there also seems to be an overwhelming prevalence of those five seemingly milder symptoms versus symptoms from previous variants. There also would not have been a sudden surge in immunity that would explain such a rapid shift. Also, see ms to be not just milder symptoms, but different symptoms. So there does seem to be something intrinsically different here. Given all we've heard about the striking mutations at the spike proteins for Omicron, it's probably not surprising since they drive so much of the virus's profile.

rsfern 5y ago
> one benchmark would be the relative severity profile versus the outgoing Delta variant, right? Agreed, and that’s what this SA study is doing. They compare to delta cases from this summer, and also non-omicron (presumably mostly delta? I can’t tell) cases from this November. They find that cases are less severe than in the summer, but not enough data to conclude any difference compared to November non-omicron. More data will tell us if it’s intrinsically milder with different symptom profile, or if the other strains in November were not delta, or if it actually only seemed milder because of undercounting prior infections, or something else
- unclebucknasty 5y ago
  I was multitasking on that last EDIT so probably not very clear. Sorry. >They compare to delta cases from this summer, and also non-omicron (presumably mostly delta? I can’t tell) cases from this November. From the article: Compared to delta infections in South Africa between April and November, omicron infections are associated with a 70% lower risk of severe disease, they said. The omicron data was collected for the two months through November. I read from that significant overlap in comparisons between both summer through November, as well as Omicron and Delta up through November. In all, that statement seems to specifically address most of your questions, as they have directly compared per the variables you seem to be questioning. The one thing they have not been able to conclude is the role immunity played in the differences. That's where I'm lobbing in my opinion (partially sourced from other reports, beyond this study) that we might be able to read into the seemingly stark shift when Omicron hit the scene, particularly WRT symptom variation. While we are awaiting more data, there does seem to be a consistency in these reports, and that consistency points to a sudden and observable difference in Omicron symptomology that would not be explained by increased immunity alone (again, my opinion, informed by the study time frames and other sources). Of course they can't conclude that yet, but I'm predicting that's what the data will show. So that was my internet layperson attempt to address your original question with regard to intrinsic virulence versus immunity. I just think it's unlikely that we're coincidentally seeing a sudden surge in immunity concomitant with the appearance of a new variant, which also happens to have a ton of mutations and starkly different spike profile.