Joshua Weitz
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joshuasweitz.bsky.social
Joshua Weitz
@joshuasweitz.bsky.social

Professor of Biology & Institute for Health Computing, U of Maryland; explores how viruses impact human & environmental health;

'Asymptomatic' (JHU Press - https://bit.ly/asymptomatic_book)
&
'Science Matters' (https://substack.com/@joshuasweitz) .. more

Joshua S. Weitz is an American biologist. He is both a professor of biology and the Clark Leadership Chair in Data Analytics at the University of Maryland. Previously, he was a professor at Georgia Tech, where he was the founding director of the Interdisciplinary Graduate Program in Quantitative Biosciences. In 2017, he was elected a Fellow of the American Association for the Advancement of Science. .. more

Biology 28%
Environmental science 26%
Pinned
New from #SCIMaP - analysis of the White House’s Proposed FY 2026 National Science Foundation Budget.

Take-home: Slashing NSF by >50% will lead to ~$11 billion in economic loss and extensive job loss and reduced training opportunities in communities nationwide.

Report: osf.io/e8rnc

a 🧵

Grad student in lab just had their GRFP returned without review. But their proposal is not on ag/crops/health. What gives?? 😡

When the NIH Director makes claims counter to evidence and says one thing (no politics) to one audience and another (NIH = research arm of a political MAHA movement) in another, we have a problem; and one that will not simply blow over.

Change depends on us.

/🧵

The @nytopinion.nytimes.com can do what it wants. Getting bothered by Douthat is time poorly spent. But contesting the transformation of NIH is essential.

The platforming of COVID 'contrarians' or what Douthat calls a 'public controversialist' might lead to more clicks, but it won't lead to better science and discoveries needed to save lives and drive an innovation economy.

As I wrote yesterday in a brief post, NIH is not an ideological toy or 'arm'.

We must continue to insist on NIH's scientific independence and the independence of research decisions supporting who does research and what research is funded, especially if its Director will not.

MAHA is a political movement driving misinformation and anti-vaccination policy, as Mark Gorton, President of the MAHA Institute said in November:

"I’ve come to this anti-vax conference with a message that we need to be more boldly anti-vax"

www.nytimes.com/2025/11/10/u...
Emboldened, Kennedy Allies Embrace a Label They Once Rejected: ‘Anti-Vax’
www.nytimes.com

“I want the NIH to be a central driver of the MAHA agenda,” Bhattacharya said. “Essentially, it's kind of the research arm of MAHA.”

Duke University Virtual Fireside Chat, Jan 27, 2026
www.dukechronicle.com/article/duke...
NIH Director Jay Bhattacharya talks 'replication crisis' at Duke panel, omits funding cuts
Throughout the second Trump administration, the NIH has frozen billions of dollars in research funding to universities. Those cuts were not the topic of discussion at a Duke Clinical Research Institut...
www.dukechronicle.com

What is this end? He claims he is intent on restoring trust, and in his words "Remove politics out of it" where it = medical research. Yet, days ago in a fireside chat at Duke Medical Center, Bhattacharya said something different.

Yes, there were too few viral tests.

Yes, asymptomatic spread was real (and critical).

But, there were still far more people to be infected beyond March 2020 with catastrophic impacts and Bhattacharya continues to minimize this harm as a means to an end.

joshuasweitz.substack.com/p/revisionis...
Revisionism in the Wake of Covid
A dialogue confronting the premise of revisionist efforts to diminish the pandemic's severity and dismantle public health institutions.
joshuasweitz.substack.com

As I describe in Asymptomatic

"Taking the right steps in spring 2020 required being realistic about the COVID-19 threat. While many scientists and public health experts were aware of the threat, the Santa Clara study presented a counter-argument that helped fuel confusion and misinformation."

We knew it was wrong at the time, and as Andrew Gelman put it, the estimates "were essentially the product of a statistical error."

statmodeling.stat.columbia.edu/2020/04/19/f...
Concerns with that Stanford study of coronavirus prevalence | Statistical Modeling, Causal Inference, and Social Science
statmodeling.stat.columbia.edu

... and that we were 50-85x times closer (as it were) to reaching herd immunity and the end of the pandemic.

But none of this was right.

Bhattacharya and colleagues study was flawed, claiming that 50-85x times as many people had antibodies (and therefore had been infected) vs. those who had a positive viral test. If this was right, then it meant the disease was 50-85x less dangerous than previously thought...

The reason is that Bhattacharya and colleagues sought to confirm their hypothesis (rathe than test it). They thought COVID was, to borrow Ioannidis' phrasing, no more than a 'house cat'.

www.statnews.com/2020/03/17/a...
A fiasco in the making? As the coronavirus pandemic takes hold, we are making decisions without reliable data
A fiasco in the making? As the #coronavirus pandemic takes hold, we are making decisions without reliable data.
www.statnews.com

Back in April 2020, Bhattacharya claimed it was 50-85x more and emphasized the 85x, likely because it sounded more extreme.

"that means that there's about 85 times more people who've had it per person that actually identified having it."

www.hoover.org/research/fig...
The Fight against COVID-19: An Update from Dr. Jay Bhattacharya
TRANSCRIPT ONLY Dr. Bhattacharya returns to discuss the results of a study testing for COVID-19 in Santa Clara County, California, and one currently underway in partnership with Major League Baseball...
www.hoover.org

In this interview, Bhattacharya claims "for every infected person who had been identified as having had the disease, there were 50 people walking around with antibodies."

But, Bhattacharya is focused on being 'right' (despite being wrong) and motivated by grievance. The roots of his grievance lie in his flawed Santa Clara serological survey. This is one of first elements of my book, because it illustrates what happens when folks fit data to narratives.

Simple-minded solutions that suggest only those in LTCs or nursing homes needed to stay at home belie the actual risk and the fact that asymptomatic and presymptomatic transmission would lead to outbreaks without massive investment in testing - which the President & political leaders ignored.

Back in March '20, public health experts understood that unmitigated spread could lead to *hundreds of thousands of fatalities* in the 40-64 age range.

In fact, and despite lives saved due to vaccinations, ~250,000 individuals died of COVID in that range:

www.cdc.gov/nchs/nvss/vs...

But as can also be seen in the table, the J shaped risk curve is not confined to 80+.

This is precisely why so many (self included) tried to raise the alarm on risks in long-term care facilities and improve entry testing and introduce cohorting as a means to reduce the risk that an introduced infection would lead to a severe outbreak.

Here is but one example from March 16 2020 from one of the most widely cited/utilized studies from Imperial College, their population level infection fatality rate (IFR) was 0.9%, an IFR that depends on demographics.

www.imperial.ac.uk/media/imperi...

As one example, Bhattacharya claims public health experts had no understanding of the difference between infection and case fatality rates, but he did:

"You could see the relative risk really, really easily in the data. It was really older people that were at high risk of dying from the disease."

Want to read the whole interview?

Here you go, reader beware:

(it's hardly a 'gift', but there you go)

🎁
www.nytimes.com/2026/01/29/o...
Opinion | A Plan to Restore Trust in Science From a ‘Fringe Epidemiologist’
www.nytimes.com
Today's @nytimes.com dialogue with Ross Douthat & Jay Bhattacharya is tough sledding. I wrote a book on how silent transmission made COVID harder to stop and drove misleading narratives. The interview continues to mislead as a means to seize more power.

a 🧵
www.amazon.com/Asymptomatic...
Asymptomatic: The Silent Spread of COVID-19 and the Future of Pandemics
Asymptomatic: The Silent Spread of COVID-19 and the Future of Pandemics
www.amazon.com

More on this soon.

Need stronger coffee.

Reposted by Larry W. Hunter

“I want the NIH to be a central driver of the MAHA agenda,” Bhattacharya said. “Essentially, it's kind of the research arm of MAHA.”

NIH is not an ideological toy or 'arm'. We must insist on its scientific independence, especially if its Director will not.

🚨

www.dukechronicle.com/article/duke...
NIH Director Jay Bhattacharya talks 'replication crisis' at Duke panel, omits funding cuts
Throughout the second Trump administration, the NIH has frozen billions of dollars in research funding to universities. Those cuts were not the topic of discussion at a Duke Clinical Research Institut...
www.dukechronicle.com

Reposted by Joshua S. Weitz

RALLY TO TAKE BACK SCIENCE! 🧪✊🔬
March 7th, 2026 in Washington, DC.

We're mobilizing the fight for science and democracy. In the face of assaults on our families, freedoms, and futures, we're taking back science!

Learn more at www.standupforscience.net/ma... (linked in bio)

Reposted by Anne Applebaum, Mariana Mazzucato, Stephen M. Walt , and 171 more

I wrote this song on Saturday, recorded it yesterday and released it to you today in response to the state terror being visited on the city of Minneapolis. It’s dedicated to the people of Minneapolis, our innocent immigrant neighbors and in memory of Alex Pretti and Renee Good.

Stay free
Bruce Springsteen - Streets Of Minneapolis (Official Audio)
YouTube video by Bruce Springsteen
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