So a great friend who I’ve not seen in years is visiting from London - current epicenter of omicron. What should we do to be responsible if we want to hang out? 1/n
Well first thing is that travel bans between places that have little difference in prevalence now or in the near future are just dumb. So don’t hate on people for traveling, especially because they can have good reasons 2/n
LFTs are obviously helpful. Two negative today build confidence 3/n
Given that, felt well comfortable indoors for a while though spent most of the time outside around an improvised fire pit involving a grill and some wood 4/n
Spending time with people you care about is important. you can do it in a way that greatly reduces the chance of anyone getting sick 5/end
Ps I like making fire. This seems an atavistic strain I cannot control
Should note “a while” is hours involving lots of chat and mulled wine
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Right now delta, which lest we forget is an extremely transmissible variant with substantial ability to cause breakthrough infections, is losing out to omicron in the US. The details are debatable, the overall trajectory is clear (from covid.cdc.gov/covid-data-tra…) 1/n
This is remarkable, but is it due to omicron dodging antibodies better than delta, or just being more transmissible, or both? We can gain some insights from this thread (by @maryebushman in my lab)
This is a crucial plot. It shows the combinations of the two key parameters consistent with what was observed in Gauteng. Not that 'population immunity' is not seropositivity, it is a representation of total immunity arising from both infection and vaccination 3/n
In one week #Omicron went from 13% to 73% of cases in the US. This is transmitting very fast, and transmission matters covid.cdc.gov/covid-data-tra…
This at a point when cases have been rising and this is already the reality in the North East - fueled by Delta nytimes.com/live/2021/12/2…
I am less sure now whether Omicron will completely replace Delta, or just be the more common cause of infection. After all, if cross protection is limited, that should matter
I am not ‘afraid’ of the virus. I am vaccinated and boosted and young (ish). I am concerned about what unmitigated transmission does to our society, and the potential of Omicron to cause outbreaks in places we don't want them 1/n
Imagine an outbreak among the team about to deliver your baby, some of whom suddenly have to isolate 2/n
Imagine an outbreak among the people who deliver your chemotherapy 3/n
To what does Omicron owe its remarkable properties? Immune evasion or inherent transmissibility. My bet is a bit of each. One thing though is beyond question - it is much better than delta at spread. Look at the household attack rate. This has implications 1/n
So Omicron is infecting roughly 2-3 times as many people as Delta, specifically in the setting of household transmission. It is not as clear outside households but remember, it is much harder to identify all potential contacts outside households 2/n
Lots of chatter about how early data show #Omicron is "less dangerous". But it is important to correct for the lag between infection and hospitalization when comparing the severity of variants with very different properties when it comes to transmission, here’s why 1/n
Imagine two viruses exactly the same in terms of severity, but one of them infects on average 3 people, and the other 1.1 (I know you can’t have 0.1 of a person, it’s an average). These are the effective reproductive numbers or Re and they determine how quickly they spread 2/n
If we start with 1000 infections with the less transmissible variant and just one of the more, we would expect the latter to overtake the former by the 7th generation (assuming nothing changes). Exponentials are wild 3/n
#Omicron data continue to accumulate, with this being perhaps the most serious indication I have yet seen about what we should expect in the next few months. Like @theosanderson says, these are increases in *daily* results 1/n
Was distracted before continuing the thread, and in that time this dropped. Once again the @UKHSA has provided incredibly prompt data collection and analysis. The upshot is that #omicron is definitely transmitting very readily indeed, and that matters 2/n assets.publishing.service.gov.uk/government/upl…
Even if Omicron infections are mild (and they might be, especially in vaccinated people) they would have to be really really mild to prevent an acute burden on healthcare that is already stretched, resulting from very large numbers in a short period of time that will add up 3/n