You might not have heard, but the northeastern U.S. is in a COVlD surge.

We use wastewater levels to derive estimates of the proportion of people actively infectious in each state (prevalence), e.g., 1 in 24 people in Connecticut.

Let me walk you through it...

🧵1/8

https://twitter.com/michael_hoerger/status/2009091661494931724

Notice that #Connecticut has excellent SARS-CoV-2 wastewater surveillance. It's "Very High" across much of the state, per CDC.

Based on wastewater levels, we estimate 1 in 24 residents are actively infectious w/COVlD. That's a 66% exposure risk in a room of 25 people.

🧵2/8

We're in the middle of a 12th COVlD wave in the U.S., with transmission particularly high in the Midwest and Northeast.

The CDC announced this week that COVlD continues to kill more Americans than breast and prostate cancer combined.

Get boosted & #MaskUp 💉💪😷
1/4🧵 Levels are "Moderate" to "Very High" in 26 states.

However, data reporting is slow, and about 1/3 of states have low-quality data this week due to the holidays and illness.

2/4🧵

We told you that 109,000-175,000 Americans would died of COVID (excess deaths) in 2025.

Today, the CDC estimates 101,000 deaths/year (flat from Oct 2022 to Sep 2024), and likely higher when considering more nebulous non-acute excess deaths (heart attack 6 months later).
1/5

https://twitter.com/michael_hoerger/status/1906756861417697313

The CDC estimates are actually higher than I would have guessed, given their methodology, which models estimates based on easily countable factors in healthcare and expert input on multiplier values. It lends credence to the PMC upper bound of excess deaths of 175,000/yr.
2/5

PMC COVlD Update, Week of Dec 29, 2025
🧵1/10

Happy New Year's Eve! #nye

Based on today's CDC data, we estimate 1 in 51 Americans are actively infectious with COVlD. That's nearly 1 million new daily infections.

Be wise. Vax up, mask up. #oneofthetwo 🧵2/10

Many states are surging presently. True levels are higher than shown in most places due to state-level reporting lags.

PMC COVID Update, Dec 15, 2025 (U.S.)

In the latest CDC data, 15 states have moderate to very high transmission.
🔹1 in 63 estimated actively infectious nationally, rising fastest in the Midwest & Northeast
🔹Very High: Indiana
🔹High: Nebraska, Vermont, Connecticut

🧵1/9 PMC estimates 1 in 26 people in Indiana are infectious and 1 in 39 in Connecticut.

MI, MS, and AR may have higher levels than shown due to poor reporting.

States AL to MS shown.

🧵2/9

PMC COVlD Update, Dec 8, 2025 (U.S.)
1/9

🔥🔥🔥Very High: Arizona (Yuma)
🔥🔥High: Indiana and Vermont
🔥Moderate: Nebraska and Alabama

Data only go through late November, and levels often increase following Thanksgiving. PMC COVlD Update, Dec 8, 2025 (U.S.)
2/9

State-by-state estimates (part 1). Arizona is Very High, but sites were only online in the Yuma area. Indiana remains high.

MI and MS have considerable uncertainty.

DC is exceptionally low.

PMC COVlD Update, Week of Nov 24, 2025 (U.S.)
🧵1/10

With CDC data operational again, the transmission map is back. The data are always a week old, so transmission is likely worse than depicted.

We estimate 1 in 116 people actively infectious and 422,000 new daily infections. PMC COVlD Update, Week of Nov 24, 2025 (U.S.)
🧵2/10

State level estimates are back. Note, the CDC changed their data processing approach in August, which tends to downplay transmission.

Does 1 in 45 in Indiana seem "moderate"?

Levels in MI may be mod/high (poor reporting).

PMC COVID Update, Week of Nov 10, 2025 (U.S.)
1/6🧵

🔹301,000 new daily infections based on wastewater-derived models
🔹1 in 162 people (0.6%) actively infectious
🔹Levels the past 2 months corrected upward by Biobot
🔹"Lull point" estimated between Nov 5-21. Rising soon. PMC COVID Update, Week of Nov 10, 2025 (U.S.)
2/6🧵

The central estimate of the forecast suggests we will surpass 500,000 new daily infections on Nov 22.

There's a 25% chance of a prolonged lull like last year. More likely, we are in wave territory by the end of the month.

PMC COVlD Update, Nov 3, 2025 (U.S.)
1 of 9 🧵

The relative "lull" in SARS-CoV-2 transmission is unlikely to go much lower.

✨1 in 209 people are estimated actively infectious, likely the lowest levels of 2025 nationwide.

Get boosted. Stock up on masks, tests, & filters. PMC COVlD Update, Nov 3, 2025 (U.S.)
2 of 9 🧵

No data presently suggest the rise of a winter wave any earlier than "usual."

If following historical trends, transmission will pick up Nov 15-29. Last year's rise was atypically late.

PMC COVlD Update, Oct 27, 2025 (US)

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 20, 2025 (U.S.)

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 Wave Update (Europe)
11 October 2025 🧵

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.

Find more here:

2/ pmc19.com/austria

PMC COVlD Update, Week of Oct 6, 2025 (U.S.)
🧵1/9

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.)
🧵2/9

#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.

BREAKING: 3 State Pharmacy Boards Still Block COVlD Boosters without a Prescription

ACIP voted against prescriptions for boosters & 47 states + DC follow that guidance.

Georgia, Missouri, & Louisiana require prescriptions.

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.

🧵2/7

I remember when they said kids don't transmit COVlD much because they are short, small, and have tiny lungs. They lied. I remember when they said COVlD doesn't transmit in schools. They lied.

PMC COVlD Update, Sep 29, 2025 (U.S.)

Summary: COVlD is everywhere.

On the back end of this unprecedented 11th wave, "times they are a-changin." In particular, COVlD levels are shifting north and east.

Notice that few states are in the highest and lowest categories. Much of the south and west have considerable transmission post-peak. Many places in the north and east are seeing steady or increasing transmission after relatively lower levels.

Overall, levels are lower than the past few weeks, but transmission remains considerable. Those relying on anecdata (friends, coworkers, and family infected) may increasingly realize we are in a wave.

We estimate nearly 750,000 new daily infections nationwide, meaning approximately 1 in 66 people or 1.5% are actively infectious.

These estimates are derived by linking wastewater levels to IHME true case estimates using methodology commonly employed worldwide, detailed on the website, noted in a pre-print. Many publications in leading medical journals link wastewater data to key metrics that matter, noted in the online technical appendix.

In this week's report, we note adding North Dakota and Puerto Rico to the heat map in support of health equity. We have been imputing ND levels since the launch of PMC 3.0 using data from neighboring states. PR continues to report qualitative levels using the CDC format but is not longer included on the CDC website.

1/8 🧵 PMC COVlD Update, Sep 29, 2025 (U.S.)

State-level prevalence estimates, AL to MS. The levels use CDC labels, which tend to have an optimistic portrayal of risk. For example, CO is listed at "low" (by our estimate 1.5% infectious).

#MaskUp at 1.5% if having lapsed.

2/8 🧵

BREAKING: COVlD transmission surges across the Northeast amid 11th wave.

CDC levels & PMC prevalence estimates:
🔹CT: Very High (1 in 18 people actively infectious)
🔹RI: High (1 in 33)
🔹NY: High (1 in 35)
🔹MA: High (1 in 37)

Quick thread 🧵 1/7 #NewYork has "High" transmission statewide & many counties are seeing "Very High" transmission, per CDC.

PMC estimates 1 in 35 people are actively infectious statewide.

A lot of sites are offline, but notice the overall coverage remains strong. Bad picture statewide.
🧵 2/7

PMC COVlD Dashboard, Sep 22, 2025 (U.S.)

The CDC reports 29 states & DC are experiencing High or Very High transmission.

The heat map is a patchwork quilt with COVlD levels varying considerably state by state.

Transmission is shifting north + east.
🧵1/8 PMC COVlD Dashboard, Sep 22, 2025 (U.S.)

COVlD levels by state, AL to MS.

Note that even levels the CDC calls "Low" like Guam at 1.5% actively infectious are at the threshold where I would tell people who have lapsed that it's time to #MaskUp.

🧵2/8

Three years ago, the American public was told in passing that the "pandemic is over."

PMC estimates that since that day, U.S. residents have experienced nearly 1 billion SARS-CoV-2 infections. Specifically, 974,190,702 infections, based on wastewater-derived estimates.

1/5

https://twitter.com/60Minutes/status/1571652540592050176

Far from harmless, recent high-quality data (e.g., PCORnet) suggest each infection leads about 30% of people to experience long-term health sequelae.

Per infection.

Some of these changes will be temporary, and others permanent.

2/5

https://x.com/fitterhappierAJ/status/1968190962523582930

PMC COVlD Report, Sep 15, 2025 (U.S.)
🧵1/7

COVlD-19 levels are "Very High" or "High" in the majority of states, per the CDC.

This includes 27 states & D.C.

🔥🔥Very High:
Alaska, Hawai'i, California, Nevada, Idaho, Utah, S. Dakota, Nebraska, Texas, Louisiana, Indiana, Kentucky, Tennessee, Florida, S. Carolina, N. Carolina, D.C., Maryland, and Connecticut.

🔥High:
Washington state, Oregon, Montana, probably N. Dakota (imputed), Arkansas, Alabama, Virginia, Delaware, Rhode Island, and Massachusetts.

PMC estimates 1 in 38 people (2.7%) are actively infectious. Wastewater-derived case estimates suggest 1.3 million new daily infections. PMC COVlD Report, Sep 15, 2025 (U.S.)
🧵2/7

Transmission is peaking nationally, but regional variation is common. Know what's happening in your state, and get the word out.

Note that the levels CDC calls "low" are still quite alarming.

California COVlD Surge Rages Higher

🔸CDC SARS-CoV-2 wastewater levels "Very High," and up from last week
🔸1 in 21 estimated actively infectious
🔸>250,000 estimated new daily infections statewide

Four figures...
1/4🧵 CDC wastewater data in California show COVlD cases increasing from the already "Very High" levels last week.

2/4🧵