Wanted to post this for discussion as we begin to hear about immune evasion of the Omicron variant. This is specific to convalescent immunity and does not study vaccine evasion.
When you hear that Omicron evades natural immunity be aware that this is the paper driving that quip. If other papers emerge please share!
I'm having a hard time understanding the details of hazard coefficients but I think people can probably get the gist of how they are coming to this conclusion from figure 1 of the paper. See plot A, daily primary infections have barely started to increase while daily reinfections are nearly at levels seen in wave 3. I think there must be some control going on to account for the fact that you can only get a primary infection once. At some point the primary infection plot is guaranteed to flatline. It seems like they could do some rough control for time since previous infection by excluding reinfections from more than 1 wave ago. If they see similar hazard ratios between waves then you could blame this on waning immunity rather than the genetic particulars of the virus. If they see only a slight decrease then it would be a combination of factors. If they see no decrease then this could be blamed purely on the bastard virus.
One final note, they didn't exclude vaccinated individuals. So this would include people who were vaccinated then infected, or infected then vaccinated as well as people who were unvaccinated with a prior infection. It would be super sweet to see this study done on those sub-populations but they claim vaccination details for their subjects were unavailable. WTH!?
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[ 4.0 ms ] story [ 19.7 ms ] threadWhen you hear that Omicron evades natural immunity be aware that this is the paper driving that quip. If other papers emerge please share!
This BBC report touches on the paper: https://www.bbc.com/news/health-59520945 importantly noting some confounding factors not discussed in the paper.