An important study- it suggests that Omicron has a much greater growth advantage among the vaccinated, and previously infected, and possibly a lower growth advantage compared to delta among those who were susceptible (not vaccinated/infected or waning of immunity)
https://twitter.com/ONS/status/1473243477244841990
This doesn't mean vaccines are not effective. It means that among the vaccinated and previously infected, omicron has a higher advantage compared to delta because it has higher escape from immunity (although both have lower infective probability compared to unvaccinated)
It's possible that intrinsic transmissibility of omicron relative to delta (apart from escape) may not be much higher, or possibly even slightly lower. But it would still have a massive advantage among those with prior immunity through vaccines/infection.
It might also explain why omicron hasn't rapidly replaced delta, and they appear to be co-circulating in what appears to be potentially different immunological compartments.
The lower representation of omicron in young children is similar to reports from Denmark- time will tell whether this is because of higher spread in young travellers early on (so not spread to this group yet), or because of a lower growth advantage due to lack of prior immunity.
Just to clarify, this wouldn't necessarily be a good thing- because it means we may have two variants occupying quite different immunological compartments so that prior exposure against one doesn't protect against the other and vice versa. Herd immunity becomes a distant dream.
It means that the two variants may be able to co-circulate for longer periods than otherwise, and those infected with one may be susceptible to the other over time.
Multilayered measures will of course work against both- so high quality well fitting masks, ventilation, limiting social contact + vaccination + boosters all very important.
It means we live with the worst of both worlds- high intrinsic transmissibility lower escape (delta) which hits the more susceptible or when immunity wanes, and moderate-high intrinsic transmissibility & high escape (omicron) which grows among those with prior infection/vaccines.
It means we live with the worst of both worlds- high intrinsic transmissibility lower escape (delta) which hits the more susceptible or when immunity wanes, and moderate-high intrinsic transmissibility & high escape (omicron) which grows among those with prior infection/vaccines.
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