Nationally, we appear to have passed the peak of our late-summer wave, and it's not pretty.
At peak:
🔹>1.3 million daily infections
🔹2.8% (1 in 36) actively infectious
🔹Transmission higher than 90.5% of the pandemic
We are showing a peak around Aug 10, but as you look closely at the graph and in later Tweets, you'll see it was bimodal, with near-identical transmission on Aug 10 and Aug 24.
The CDC consistently corrects historical data, so in hindsight, we might expect the official peak date to flip to the 24th, or for the stats on the 10th to jump higher.
We had expected that Friday's data release might show this was the largest summer peak all-time (by the slimmest of margins), but the prior week's data were retroactively corrected downward by about 5%.
This is a common occurrence, which is why it's important to focus on the big-picture forecast (very bad transmission the remainder of 2024) as opposed to minute details.
Let's walk through the details in this Thread....
PMC COVID-19 Forecasting Model, Sept 9, 2024
🧵2/7
The current year-over-year graph on Covid transmission is troubling. We just had the worst August of Covid transmission in the U.S.
We are likely to have our worst September, worst October, and potentially worst November of transmission.
We expect to bottom out around 850,000 daily infections in early November, before the winter surge picks up.
These new monthly records for Covid transmission are the consequence of #LaissezFairePublicHealth, especially the 1-day isolation policy, but more generally that public health officials are not describing transmission frankly and the need for multi-layered mitigation.
PMC COVID-19 Forecasting Model, Sept 9, 2024
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Zooming in, see the forest for the trees: About 74 days in a row with 1 million daily infections.
The peak date is somewhat arbitrary, and either Aug 10 or 24 may be estimated the peak in hindsight.
PMC COVID-19 Forecasting Model, Sept 9, 2024
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Statistics to reinforce the significance of the ongoing pandemic:
🔹1.1 million daily infections on average the next month
🔹2.2% (1 in 45) actively infectious any given day of the next month
🔹High-risk in classroom-sized settings
🔹>1.5 million resulting Long COVID cases from infections derived during the next month
PMC COVID-19 Forecasting Model, Sept 9, 2024
🧵5/7
This is the current heat map for Covid transmission. We released this Friday, given the ongoing debate about the CDC coloring their map in cool blue using the same data.
Here are regional estimates of transmission. Note that you can estimate the percent of your state actively infectious by looking up the CDC Level on their website and multiplying it by 0.330.
These are approximate estimates and higher quality in states with more and longer-standing wastewater sites.
Go here, select a state from the drop-down:
For example, in Louisiana the most recently-reported CDC Level is 8.31.
8.31 * 0.330 = 2.74, signifying that 2.74% of the state is estimated to be actively infectious with Covid.
Take 100 divided by that number to get the "1 in ____" statistic. For example, 100/2.74 = 36.45, signifying that 1 in 36 people in Louisiana are estimated to be actively infectious.
Watch your decimals, and remember these formulas can't just be thrown at any random wastewater tracker.cdc.gov/nwss/rv/COVID1…
PMC COVID-19 Forecasting Model, Sept 9, 2024
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Here's the complete dashboard. Use, crop, improve, and share as desired across other platforms and the web. Tag me if helpful.
Read the full report and technical appendix online: pmc19.com/data
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Transmission typically accelerates in mid-November.
We are currently in a relative 'lull.' We estimate about a quarter-million new daily infections with 1 in 185 people actively infectious. Still bad, likely to get worse.
1/9 🧵
PMC COVlD Update, Oct 27, 2025 (US)
Our forecast through November 8 calls for flat transmission.
Nothing yet indicates the onset of a winter wave, but it would also be atypical for the lull to last much longer than another 2-3 weeks.
2/9 🧵
PMC COVlD Update, Oct 27, 2025 (US)
We estimate 264,000 new daily infections during this 'lull' period.
Biobot data have returned. Our substitute data from WWS last week correlated r=.97 (near perfect) with that, but Biobot did retroactively increase recent estimates.
SARS-CoV-2 transmission has fallen.
🔹1 in 191 (0.5%) actively infectious
🔹"Lull" levels at 20% of the summer peak
🔹255,000 new daily infections (still concerning)
Many will knock out higher-risk activities the next 2-4 weeks.
🧵1/11
PMC COVlD Update, Oct 20, 2025 (U.S.)
"Lull" transmission remains dangerous:
🔹1.8 million estimated new weekly infections
🔹>90,000 estimated new #LongCOVID conditions from this week's infections
🔹>500 excess deaths to result from this week's infections
🧵2/11
PMC COVlD Update, Oct 20, 2025 (U.S.)
Exposure risk during "lull" transmission remains high when engaging in many social interactions.
Interacting with 25 people yields a 12% chance of exposure. 100 people? 41% chance of exposure, assuming no testing/isolation.
The PMC website includes an international directory of websites with COVlD wastewater monitoring. It is more up to date than the directories of the EU and WHO.
Let's review what's happening in Europe...
1/
Data in #Austria show a rising COVlD wave. The x axis (bottom) has infrequent labels, but the data shown go through October 8th.
An estimated 1 in 81 people are actively infectious during the ongoing 11th wave.
The "shutdown" has created a blackout at the state level.
Transmission is half that of the peak one month ago, and we anticipate a relative national "lull" in early-to-mid November, albeit still at dangerous levels.
Our model uses a combination of CDC and Biobot data, so we are able to estimate national statistics despite the CDC data going offline. On the map, note that Puerto Rico continues to update; they use a CDC-style system but were dropped by the CDC long ago. For full methodology, review the technical appendix on the website.
PMC COVlD Update, Week of Oct 6, 2025 (U.S.)
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#DuringCOVID is today. We estimate >600,000 new daily infections. This is about half the peak on September 6.
Notice current levels are similar to the estimated peaks of the first 3 waves.
PMC COVlD Update, Week of Oct 6, 2025 (U.S.)
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Weekly estimates:
🔹4.5 million infections
🔹>200,000 resulting long-term health conditions
🔹>1,300 resulting excess deaths
Key points in my letter to the pharmacy boards. 🧵1/7
Georgia law indicates that the pharmacy board is to follow ACIP. They do not dictate further nuance. Georgia continues to require prescriptions, going against the spirit of the law, ACIP, and 47 other states.
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Louisiana law tells the pharmacy board to follow ACIP. ACIP says do not require a prescription, and 47 other states agree.
The Louisiana pharmacy board continues to require a prescription.