PMC COVID-19 Tracker, Dec 11, 2023
The surge continues.
Today:
πΉ1.2 million daily infections
πΉ1 in 41 infectious (2.5%)
In 4 weeks (Jan 8):
πΉ1.6 million daily infections
πΉ1 in 30 infectious (3.3%)
1/
A few key methodologic updates. 1) Biobot correct levels downward for the past two weeks, so you might notice that this week's estimates seem similar to last week's or marginally lower.
2) Our forecasting model uses a combination of historic data (situation past several years) and current data (past 4 weeks). In the historic model, we switched from using mean-type data to median-type data. This avoids overestimating levels based on the BA.1 surge and allows us to predict accurately a little faster, rather than predicting high and waiting for the current 4-week's data to correct it.
3) The forecasts depend a lot on the most recent week's data. To the extent Biobot is accurate or inaccurate in real-time, this leads to divergent forecasts.
You'll see the forecasts differ considerably (1.3 to 1.9 million daily infections) in 4 weeks.
2/
However, they mostly agree on the peak. It could be as early as Jan 1 or as late as Jan 15. It's a moot point. Transmission will be similar across that timespan and the weekly reports lack the precision to say whether it will peak on the 4th or 9th, for example. Early Jan will remain bad.
Details:
The real-time model (purple) anticipates the highest surge levels. This assumes that Biobot real-time reports are accurate, but they were substantially corrected for the past two weeks, and there were some issues with real-time accuracy during the summer wave. The turtle model (green) discountβs the most recent weekβs data as an aberration, assumes transmission should be corrected upward a little, and predicts a steady rise with peak around January 1. The cheetah model (yellow) says that because last weekβs data were corrected downward, this weekβs estimate should be too, so itβs much more conservative on the next several weeks. The average of all models (red) guides forecasted numbers for the next four weeks. A month from now, we will see about 1.6 million new U.S. cases per day (range of 1.3 to 1.9 million across forecasting models), with 3.3% of the U.S. population or 1 in 30 people actively infectious.
Zooming out, you'll see that we're in a very bad place historically. With the divergent forecasts, it's merely a matter of whether this is the 2nd biggest U.S. COVID surge or 4th biggest.
The #LongCOVID cases resulting from these infections may top 400,000/week.
3/
These are the chances of interacting with someone infectious on Dec 11, based on the total number of social contacts.
Interact with 10 people = 22% chance someone is infectious.
This helps explain why so many kids are getting sick at school lately.
4/
As of Dec 11, these are the updated chances of interacting with someone infectious on Christmas Day, based on the size of gathering(s).
At 6 people, the chances of interacting with someone infectious are the same as rolling a "1" on a die. At 20-25 people, it's a coin toss. 5/
In the U.S., the current surge will peak sometime between Jan 1 and Jan 15. These are the chances of interacting with someone infectious around New Year's Day, near the peak.
6/
Here's the full PMC Dashboard for Dec 11 to Jan 8.
You can read the full report here:
Thank you for your continued questions, suggestions, gratitude, and sharing across other platforms. Please offer any success stories to encourage others.
There's a lot of dichotomous thinking about #COVID risk on #airplanes.
Some believe it's completely safe, others completable dangerous.
I minimize flight travel and wouldn't fly without a fit-tested high-quality mask (N95 or elastomeric respirator). Here's why. π§΅
1/16
Field research from @sri_srikrishna found that across 3 models of aircrafts, they had an air cleaning rate of 10.9-11.8 air changes per hour (ACH).
A U.S. operating room should have 15 ACH, so flights are pretty good, right?
Wrong. I'll explain why.
2/16
10-12 air changes per hour (ACH) on a flight sounds good, even overkill, right?
Actually, no.
If the air has good mixing, the best case scenario is that each air change is still imperfectly efficient, cleaning out about 2/3 of the air each air change.
PMC COVID-19 Tracker, Dec 4, 2023
The U.S. surge is worsening faster than anticipated.
Today:
πΉ1.2 million daily infections
πΉ1 in 38 infectious (2.6%)
In 4 weeks (New Year's Day):
πΉ1.8 million daily infections
πΉ1 in 26 infectious (3.9%)
1/
You'll note the diverging forecasts. Biobot #wastewater levels increased more than anticipated this week, and they updated last week's numbers upward too.
The cheetah forecast (yellow) assumes this week's levels will also get revised upward like last week's. The turtle model (green) ignores this week's data as an aberration. The real-time forecast (purple), which assumes all real-time estimates are accurate, is barely visible behind the red line. The red line is the composite average of all 3 forecasts.
You'll notice the blue line (wastewater levels) and red line (forecast) overlap marginally. Biobot reports levels for Nov 29, and we carry them forward in the forecasting model through Dec 4 (today). Transmission is accelerating so much, usually this 5 day lag isn't even visible graphically.
2/
This table shows how additional social contacts increase risk today (Dec 4).
π₯10 people (daycare, team meeting) = about a 1 in 4 chance someone has infectious COVID
π₯π₯30 people (large K-12 class) = over a 50% chance someone has infectious COVID
We're entering the 8th pandemic wave, likely surging to >2% infectious (>1 million cases/day) in a month.
Today's numbers:
πΉ 1.41% (1 in 71) are infectious
πΉ >670,000 C0VID cases/day
πΉ>34,000 #LongCovid cases/day
1/
Note that the different forecasting models show high convergence.
December 11 by the Numbers:
πΉ 2.25% (1 in 44) likely to be infectious
πΉ >1 million anticipated C0VID cases/day
πΉ>50,000 resulting #LongCovid cases/day
2/
Zooming out to the full #pandemic, there is no debate we're in an 8th U.S. C0VID wave, likely entering a "surge" in my view. That's not a word I take lightly.
There's more transmission than during 54% of pandemic days.
#MaskUp #VaxUp π·π
Today's Numbers:
πΉ 1.27% (1 in 78) are infectious
πΉ >600,000 C0VID cases/day
πΉ>30,000 #LongCovid cases/day
We will pass the late-summer wave's peak in just over a month.
1/
The different forecasting models reach a strikingly similar conclusion about where we'll be in a month: very bad.
November 27 by the Numbers:
πΉ 1.76% (1 in 57) are infectious
πΉ >800,000 C0VID cases/day
πΉ>40,000 #LongCovid cases/day
2/
Forecasting nuance:
Alt Model #1 (turtle) thinks the current real-time numbers are an underestimate, and it ignores the most recent week's data. Alt Model #2 (cheetah) accounts for recent errors in the real-time numbers; with low error, it maps on very closely to the real-time (red) line. The black line shows the composite used for reporting estimates. Note, everything converges in 4 weeks.
Zooming out to the full pandemic, you can see that we are entering the 8th wave.
Today, there is more transmission than during 50.6% of pandemic days. It's a coin toss as to whether any particular day of the pandemic has had more or less transmission than today. π·π 3/