Thread by @BillHanage

So a brief thread on the state of the pandemic in the Boston area. It is quite plausible that about 10% of the population is currently infected, more in some age groups than others. A *lot* of omicron. What next? 1/n

First that 10% figure. Earlier this week, the local school district tried pooled testing before reopening after the holidays. It didn't go well as 157/362 pools came back positive, that's consistent with about 5% of the population being positive

https://twitter.com/BillHanage/status/1478921415868956683?s=20

2/n

(we don't know exactly, because the individual swabs never got tested. But some pools will have had >1 positive swab by chance, so it is probably more than 5% although way short of some of the numbers in the email parents received. Not great communication there) 3/n

Anyway, that was monday. And now it is Friday. The generation time of omicron is probably shorter than delta, so that will have been time for the numbers to grow more, maybe even a couple rounds of infection 4/n

The daily case numbers are not inconsistent with this, especially when you consider that numerous factors mean this is an undercount (access to testing, some people positive on an antigen test just isolate, some currently asymptomatic) (from cityofcambridge.shinyapps.io/COVID19/?tab=n…) 5/n

~500 cases/day in a city of 100k might seem very different from 10%, but wait: Prevalence is number currently infected, so you need to add up the last few days. Once you do that, account for under detection and the steep slope of the epidemic curve, that 10% is v plausible 6/n

And this is Cambridge, which has historically generally had lower case rates than some surrounding communities. We can look at the dynamics there with the wastewater data from @MWRA_update and @BiobotAnalytics again that is a very steep curve 7/n

Looks like more in the South system than the North, although hard to interpret. Also the faintest hint of a peak, although *way* premature to get excited about that although... 8/n

These data from the UK's amazing @ONS infection survey show considerable differences by age groups and suggest peaks approaching 10% in a very boosted population with a lot of immunity from recent prior infection (sort of like Florida but with boosters) 9/n

Speaking age, a local peak in cases in the next week is entirely plausible to me, but what will matter for at the population level is severe outcomes, and they are expected to be more common in older people. This, from South Africa (HT @tomtom_m) shows the lag there by age 10/n

Older people tend to get infected later. We have more older folks, but they are also more vaccinated. So I don't want to make strong predictions on this other than to say be cautious about anyone making strong predictions 11/n

(for parents - look at the under 10s in the S Africa data. More evidence that they show different dynamics to older ago groups!) 12/n

One prediction we can make is that the immediate risk to healthcare matters, which is why I contributed to this to try and detect when that is happening. Even without things getting markedly worse, we are in a bad place already due to existing strain

https://twitter.com/jeremyfaust/status/1479244541127446531?s=20

13/n

So I am comfortable stating that things will get worse before they get better. How much worse I don't know. But there are things that we can do. I wrote this for the UK audience, but much is relevant here theguardian.com/commentisfree/… 14/n

& this featuring the likes of @RickABright and @celinegounder among others makes great points. One smart one from @llborio because antivirals need to be given early on in infection, vulnerable people w a +ve test should get a prescription on the spot nytimes.com/2022/01/06/us/… 15/n

We will see if the peak happens in the next week. For now, if you are infected, I hope you recover soon and without incident. If you need care, I hope it is there for you. And omicron should turn around soon. It won't be pretty, it should be quick 16/end