In 1519, the year Spaniards arrived in Mexico, the population there was between 15 - 30 million. By 1600, that dwindled to 2 million. For lots of reasons, but as much as 70% of those deaths were the result of an UNKNOWN hemorrhagic fever. Let's talk about the mystery of the COCOLIZTLI epidemics.

🧵Remember the preprint claiming SARS-CoV-2 has a "synthetic fingerprint"? It said a restriction map was "extremely unlikely to have arisen by random evolution.” I took its claims seriously. The "synthetic fingerprint" hypothesis collapses. My new preprint explains why. arxiv.org/abs/2510.23833

We’ve identified a highly divergent betacoronavirus from South American bat that encodes a functional furin cleavage site. Another fascinating reminder of how diverse coronavirus evolution is in wildlife reservoirs. #Virology #VirusEvolution #Bats #Coronavirus www.biorxiv.org/content/10.1...

Good science needs time. Finally, a functional furin cleavage site found in the S1/S2 junction of a bat coronavirus. 🧪 www.biorxiv.org/content/10.1...

Women in the US are now being forced to have babies and carry in the most painful way possible. The #autism announcement yesterday was not based at all on science. The correlations found in that 1 study are not sound: the follow up times were unbalanced, leading to bias and misleading associations.

Occultation! Venus is about to disappear behind the 5% lit Moon! #astronomy #astrophotography #Occultation #Moon #Venus @stormhour.com @photohour.bsky.social 1/2

My favorite thing: one of the CDC's COVID-19 risk factors is vaccination status, so one has an increased risk when discussing the COVID-19 vaccine prior to being vaccinated. So meta! And so meaningless from the ACIP. This #ACIP is not helping Americans.

Listening to the ACIP meeting in the background.... When voting, there were several comments about postponing the Hep B vote until a future meeting, but the motion was actually that the Hep B vote be postponed indefinitely.

Excellent news and hard work pays off - one of our studies, "Health outcomes of women with Gestational Diabetes Mellitus in North West London: a 10-year longitudinal study" accepted in BMJ Public Health 🥳🎉

#Birdflu still circulating: Scientists are testing a #birdflu vaccine in seals. If results show promise, the shots could be given to endangered Hawaiian monk seals. #H5N1 birdflu virus has devastated marine mammals globally. It tore thru Argentina's Valdés Peninsula killing ~17,400 seal pups 👇

My latest for @jama.com:

@zachhensel.bsky.social and I have a new paper on the origin of SARS-CoV-2! 🧪 There are a lot of reviews on the topic already, so we tried to do something different: characterize "lab leak" scenarios, and directly address those on SARS-CoV-2's furin cleavage site.▫️1/9 doi.org/10.5802/crbi...

Our 2021 review on COVID #vaccines was open access and provides a full report of effectiveness. Thanks to @carlzimmer.com and @apoorvanyt.bsky.social for their terrific article in NYT 👍 www.nature.com/articles/s41... www.nytimes.com/2025/09/02/h...

There was a slew of false statements made about COVID19 mRNA vaccines yesterday. I can’t recommend highly enough this article from May by Dr. Deborah Fuller to clear up a lot of the chaff.

Show me these data and I will find you at least 30 confounders. The language will be most important, particularly how strong (that is, poor) are the report's claims of causality. www.wsj.com/health/healt...

Lots of disturbing takeaways from the RFK Jr hearing, most prominently that he's listening only to Bhattacharya and Makary - non-experts - about vaccines rather than others (or reading any papers). However, there's another major question:

He is a predator. He will prey upon the nation and the world if he is not stopped. Necessary reading from @gregggonsalves.bsky.social www.thenation.com/article/soci...

In under 24h following the newly identified outbreak of #Ebola in the DRC, the virus has been isolated, sequenced and the virus sequence data made publicly available. virological.org/t/the-16th-e...

RFK Jr.’s tenure as HHS Secretary has been a disgrace. He’s destroying our public health system and putting millions of lives at risk. He is wholly unfit to serve in this role and should resign immediately.

gift link to dr. susan monarez’s piece in the wall street journal this morning.

Florida plans to end school vaccination mandates, the first to do so. The state's controversial surgeon general compared the requirements to "slavery." Joseph Ladapo says "people have a right to make their own decisions, informed decisions"👇

Your periodic reminder that mRNA vaccines are a scientific and public health game-changer. Those that have been approved have passed stringent efficacy and safety checks. They protect you and your child against potentially fatal diseases. You may, however, get a sore arm.

Dr. Paul Offit, a prominent voice on vaccines and frequent critic of RFK Jr, is blocked from participating in FDA’s vaccine advisory committee. HHS says his special government employee status expired. Offit says FDA had asked him to stay on 2 more years: www.cnn.com/2025/09/02/h...

Our 2021 review on COVID #vaccines was open access and provides a full report of effectiveness. Thanks to @carlzimmer.com and @apoorvanyt.bsky.social for their terrific article in NYT 👍 www.nature.com/articles/s41... www.nytimes.com/2025/09/02/h...

Bullies bully. It’s what they do. Leaders lead. It’s what they do. You tell me who is the leader and who is the bully. Don’t let anything distract from the fact that what is at risk is health not the fragile egos of men. Fight for health not for clout.

Yesterday the president demanded that evidence about Covid vaccines be shown to the public. Today @apoorvanyt.bsky.social & I run through some of the studies made public over the past 4+ years that show that the vaccines work. Gift link: nyti.ms/46k17Tq

Today is publication day for this beautiful thing. I hope that it will tell a broad audience what historians of science have now long recognized: that alchemy was not a superstitious aberration but rather, an important phase in the history of ideas and of manufacturing.

This 🧵 is long so please bear with me. It is compiles evidence in a historical timeline on how effective #COVIDVaccines are. When a pandemic ends we quickly and easily forget the tools that got us out of it. So here is my labour day gift to you prompted by this headline.

US public health, global health sec, & science is facing unprecedented threats & intentional erosion. During COVID-19, I think so many of us felt that this horrific global event would bring us together - a pandemic requiring community partnership & trust in science. (1/5)

Joined my former boss @drtomfrieden.bsky.social and @mkraju.bsky.social on @cnn.com today to discuss recent CDC changes youtube.com/watch?v=3zKG...

Good article from Sen Sanders. However, why must he resign - why cannot he be removed? www.nytimes.com/2025/08/30/o...

I’m so grateful that I have tenure and the academic freedom to call it like I see it. “Dr. Kathleen Bachynski, a professor of public health at Muhlenberg College, described Kennedy’s comments as “absolute gibberish” and slammed the HHS secretary as a “dangerous buffoon” who is “threatening us all.”

Washington Post EDITORIAL BOARD has had it with RFK, Jr. [Gift link] wapo.st/4lLZOkH

In a functional government, this would be a five alarm fire where Congress calls in Kennedy and asks him what the fuck is going on

Enough is enough. The health of the country is in danger. Read our resignation letters: insidemedicine.substack.com/p/breaking-n...

If there's any sign that the immunization schedule will be overhauled by RFK Jr and the crazies currently in the ACIP - it's this 👇. Look out for news on that in the coming weeks.

Re-reading the report of the Social Security whistleblower, it is striking how many times good people within SSA tried to keep DOGE from committing crimes. Here's my understanding of the timeline 🧵

A closer look at lithium orotate, after that lithium-Alzheimer’s paper. It has a complex history!

🚨🧵My latest: As measles took off in Texas, the Trump administration took actions that prevented CDC scientists from responding. The outbreak became the biggest in 30 yrs. It’s far larger considering the outbreaks it sparked in other states & Mexico. kffhealthnews.org/news/article...

Stanley Plotkin shares insights from his legendary career in vaccine development, discussing breakthroughs in polio, rubella, and rabies vaccines, and reflecting on today’s challenges in public health and vaccine confidence. www.youtube.com/watch?v=HH9G...

The claim that aluminium in vaccines causes autism has been debunked “again and again” go.nature.com/4mY7OQQ

The White House wants you to forget how many lives were saved by #publichealth leaders, particularly: Fauci. www.whitehouse.gov/articles/202...

“Among those laid off in the CDC include employees who help other countries track violence against children as well as those who work to prevent child abuse and teen dating violence. “There are nationally and internationally recognized experts that will be impossible to replace”

It would be a joke if it weren't true. Published today by the White House: www.whitehouse.gov/articles/202...

This should drive American scientists - and Americans in general - crazy: a new study on a H5N8 #mRNA #vaccine (in mice), from a team in Russia. Good results, well done to the researchers - it's a shame that politics blocks this from being pursued in the States. www.mdpi.com/2076-393X/13...

Do you have a track record of producing top quality research and policy analysis? Do you have a detailed understanding of health policy and its political context? Take a look at our Senior Fellow vacancy and apply by 31 August. #researchjobs www.nuffieldtrust.org.uk/job/senior-f...

Hey cool, astronomers found a new moon of Uranus (steady there, jokesters) in JWST images of the planet! science.nasa.gov/blogs/webb/2...