Sue writes:

Most Cherished TWIV team,

I`m in sunny Etruria and had some contact with Vincent over the translation of Christian Drosten`s podcast early in the pandemic. I`m an assiduous listener of both podcasts! Infinite thanks for sharing with us all, I`m not sure you have any idea just what a gift this is to the rest of us! 

Please can I beg you to take a look at this retrospective cohort study comparing CSVT incidence (in the US) after mRNA vaccination and after Sars-CoV2 infection and discuss its implications – it has some (admitted by authors) limitations BUT some important points seem to emerge from the inevitable fog:

1) These CSVT events are very rare anyway, so difficult to quantify (even to be sure they are generally accurately diagnosed). Therefore we do not actually know the incidence in the general population, but they estimate it as about 0.41 per million over a two week period.

2) In the 2 weeks after mRNA (Moderna/Pfizer) they detect circa 4.1 per million

3) After Astra Zeneca, from a different database: c 5 per million

4) Over 2 weeks after Covid diagnosis: c 39.0 per million! 

5) They also look at another similar atypical coagulation pathology (also thrombotic thrombocytopenia or TT) occurring in the portal vein (PVT). This yielded: rate of PVT after Covid of 436.4 per million, after flu 98.4, after mRNA vaccination 44,9

Conclusion: 1) risk of CVT is much lower after vaccination than if you catch Covid. 2) mRNA vaccines as looked at here may also similarly be triggering rare cases of VITT

My reasons for concern:

The consequences of the insistent media-mediated denigration of AZ have been really serious in Europe. I have access to the domestic TV channels of France, Germany and Italy and have followed with increasing horror the devastating effect of this on the already poor vaccine roll out in these countries. People are refusing AstraZeneca and often leaving the centres without a vaccination – in some German regions they even had the bright idea of giving people a choice, with predictable consequences.

I`ve been puzzling over this whole affair since the beginning, so much made no sense at all. One thing missing all the time was any reference to vaccines other than AZ (until now with J and J). I noticed that there was never an evidence-based official statement that these events were definitely not happening with the mRNA platform (yes, I am aware of the association of TT with specifically adenovirus vectors in the past in a different medical context). Also with all the uncertainty around such rare events how to justify the effective destruction of the reputation of a currently vital vaccine outside the US? The study:

The above study is reporting, with whatever caveats, an incidence of 4 per million for the mRNA vaccines. This is a rate very close to what has been reported for AZ and which led to the pausing roll outs in the middle of a raging pandemic and in a context of a paucity of vaccine supply. This has inevitably led to death and misery in Europe and possibly elsewhere.

Please, please could you air this matter and maybe throw some light on it. I can`t emphasize enough that the whole affair is actually costing lives in Europe.

In infinite gratitude anyway, wish I could send you some oil from our olives but it would never get there………


Charles writes:

Hello TWiVers;

Wonderful day for a hike in Chapel Hill, NC.  68F, 20C with low humidity.  A great time to listen to TWiV and think.

Today’s thoughts turned to the J&J vaccine and the media reporting about the risk.  The media has been using six cases for the numerator and 6.8 million as the denominator.  I have no problem with the six cases, but the 6.8 million is way off.

First adjustment: With a 6-13 day delay (21 if you look at the FDA news release) between injection and symptom onset, we need to go back in time (or wait a bit longer).  Going back to April 1, the number of injections was around 4 million.

Second adjustment (thanks Dr. Racaniello for this one and the next): All six of the patients with cerebral venous sinus thrombosis (CVST) were female.  54.4% of those vaccinated in the US have been female.  Applying that to the 4.0 million knocks the denominator down to about 2.2 million.

Third adjustment: The 6 patients were between 18 and 48 years old.  I could find data that broke out 18-49, so that is what I am going to use.  The percent of 18-49 year old people receiving any COVID-19 vaccine is 37.6%.  This is not really fair, because the J&J vaccine came later, after a lot of older people had already received a different vaccine.  I am going to WAG 50%.  That knocks the denominator down to 1.1 million.

I come up with about 1 in 183,000 cases of CVST per person at risk.  That is still very rare, but a far cry from the over one in a million chance the media has reported.  There are about 59.5 million females between 18 and 49 in the US.  That works out to about 325 cases of CVST for the country if every vulnerable person (female 18-49) is vaccinated.  I don’t want to minimize the tragedy for the 325 people, their family and friends, but that is far fewer than those killed by COVID-19.  Looking just at the 18-29 year old people, 1957 had died of COVID-19 as of March 31, 2021.  32 people 18-24 died on 4/15/2021 (the lowest point in over a year).

My gut tells me that if I was a young woman, I would hold out for an mRNA vaccine.  My brain tells me, if it is going to take more than two weeks, go for whatever vaccine I can get today.  If the J&J vaccine was the only one available, the time I would need to decide to take it would be way less than 0.68 seconds after seeing the data.

Bottom line: Don’t miss a chance to get your shot.



PS, This is the last of my TWiV binge emails for today.  I hope I did not go over my limit.


Ana writes:

Howdy TWIVers!

I am writing to tell you how much I appreciated the talk you had with Dr. Nadine Lamberski. I am a Brazilian poultry veterinarian that doesn’t appreciate being a clinician as much as being a researcher.

I was first introduced to TWIV in 2011, when you went to Brazil and recorded an episode from a virology conference held in Atibaia, Sao Paulo.

Flash-forward 4 years, I moved to California to go to grad school at UC Davis. I was there for 4 years for my PhD plus one year doing a residency in poultry medicine. I am now living in Calgary (Canada) while still working at UCD as a researcher, remotely — let’s see how long my boss will appreciate my work from a distance given I am not in Davis to help the rest of the lab clean chicken poop from our experimental units. 

My PhD research was on infectious bronchitis virus, a gammacoronavirus of chickens, and the immune responses elicited after challenge experiments with IBV. Infections with IBV are often local, affecting the upper respiratory tract (mostly tracheas). High systemic levels of anti-IBV IgG (or IgY) does not correspond to protection. It seems protection is more likely to occur when high levels of local IgA and IgG are present (generally measured in tears or tracheal washes). It also seems that CELL-MEDIATED IMMUNITY plays a major role in protection, especially CD8 T cells. I was SO THRILLED to hear episode 736 with Dr. Alessandro Sette. T cells are BOMB and so underrated. 

Anyway, I just wanted to point out that we have been dealing with infectious bronchitis in the field for several years, it’s an endemic disease, and we use live-attenuated vaccines, which speed up virus evolution since we have wild-type strains and vaccine strains interacting, often resulting in mRNA recombination in addition to the point mutations that occur during viral replication. Our issue with IBV in poultry isn’t going anywhere, us poultry vets just try to control IBV the best way we can and choose our live vaccines carefully to avoid introducing a bigger problem than the original one.

Dr. Lamberski was spot on when she said vets wouldn’t have let this COVID madness happen if they were in charge. Vaccines are no miracle-makers. People who work with production animals know that if you don’t have a solid biosecurity program, the vaccines don’t have the expected effect on the flock or herd. Hard to see a light at the end of the tunnel when you see people, for instance, in my country (Brazil), having parties, travelling, and acting like nothing is happening while there are 4,000 people dying of COVID every day.

It warms my heart listening to you. It reminds me of why my scientist side speaks louder than anything else, despite the frustrations that the job entails. Keep up the good work!

All the best,

Ana da Silva

John writes:

Drs TWiV:

After being sacked by the odious rightwing owners (from Toledo) of the Pittsburgh Post-Gazette, Pulitzer prizewinning cartoonist Rob Rogers’ work is now available only to his patrons, of which I am one.  But I think that with this link you’ll be able to see it too.  And if this qualifies for a reader pick, consider it submitted.

(Also, BTW, an old college pal who became a veterinarian near Philly and who has far less joy after the death of his wife from cancer a couple yrs ago, was immensely cheered by the Nadine Lamberski podcast.)

Best regards,


Randy writes:

Hello wonderful twin team! My wife and I discovered TWiV this past year and it has brought us together for a common interest like almost nothing else ever has. Neither of us are scientists but we both have technical degrees and backgrounds so maybe it’s just the nerd in both of us… Regardless thank you.

I’m just writing to tease Kathy about her seeming lack of knowledge of  Michigan’s land grant college which you all discussed in TWiV 746.

As a Michigander myself and a life long Wolverine (Go Blue!) I try to conveniently misremember anything good that has to do with Michigan State. But I do need to inform Kathy and you all that Michigan State is Michigan’s land grant University. When I was growing up my dad used to laugh and call Michigan State “Moo U”.  Which to this day still makes me laugh and something I tease my Spartan-graduate brother about to this day.

All the best to everyone,

Currently 58F, 14C

Cheryl writes:

A colleague of mine said she wasn’t encouraging her adult son (20) to be vaccinated because he, “showed her evidence from John’s Hopkins that said the VACCINE could cause male infertility.” I’ve looked for hours and the only reliable sources I’ve found state there is a risk from contracting the virus, not getting the vaccine (aside from a drop in sperm motility associated with fever.) Please clear this up for me, as I want to make sure I have accurate facts to share with my colleagues.

Thank you to you all for this invaluable podcast!


Our greatest glory is not in never falling, but in rising every time we fall. – Confucius

Félix writes:

Hey TWIV team.

It’s been more than a year since I started listening to y’all. The pandemic has been a wild ride so far, but thanks to your help, I’ve been able to keep myself sane and the people around me safe.

Anyways, on to the topic. I live in Chile. Here, we started vaccinating people at the beginning of February starting from the most-at-risk populations (retired folks, healthcare personnel, people with comorbidities, etc) and continuing down the priority list. Now we’re vaccinating the general population at or above 48 years of age! Kudos to everyone involved, for it’s been a major challenge to do this campaign in an orderly fashion.

We’ve been using Sinovac’s Coronavac vaccine for about 90% of the patients, reserving the few Pfizer doses we have for immunocompromised folks. Coronavac is an inactivated virion vaccine, and therefore the expected effectiveness is lower than Pfizer’s. However, since Sinovac’s phase III trials weren’t the most consistent, the exact effectiveness isn’t as well understood as it is for the Pfizer vaccine.

This is why the Ministry of Health has released the results of a cohort phase IV study, based on the observed vs expected outcomes in the immunized patients so far. This study has been huge, at least for me, to understand what we’re talking about.

I’m linking the english version of the press release at the end of this email.

They will be updating it monthly. If anything major comes up, I’ll be sure to notify y’all.

Thank you for your continued work. What you do is akin to public libraries and road luminaries: it’s stuff that’s not “sellable” per se, even though it can have huge positive effects for everyone involved. 

Thanks. It truly makes a difference.

– Félix

Ali writes:

Dear Team TWIV!

My mother-in-law sent the family an article about an Israeli company SaNOtize’s Nitric Oxide Nasal Spray (NONS). Despite my obsession with all things virology (and TWIV!), I am far from being a scientist. Is this new nasal spray as good as it sounds? If so, can you explain how this treatment might fit into the global fight against SARS-CoV-2?

Here is a link to the press release of SaNOtize and an article from the Times of Israel. 

Thank you for all that you do to keep us informed!


(From a stunning spring day in Portland, OR with a high of 78 F/45 C.)

Erin writes:

Hi TWIV team,

I’m wondering if you’d seen this manuscript, and what your thoughts are. My impression is that this is really low-level evidence for vector-borne transmission of SARS-CoV2, but I’d love to hear your more detailed analysis of any useful points from this study and what the major red flags are.

Thanks for your ongoing efforts, I’ve been a listener for years so you’re my go-to-virologists 😉


Erin Lashnits, MS, DVM, PhD, DACVIM (she/her)
Clinical Assistant Professor
Small Animal Internal Medicine
University of Wisconsin School of Veterinary Medicine

Lana writes:

Bonjour Team TWiV!

First, a big thank you for all your work! I have really appreciated your pandemic guidance – as a veterinarian I never expected I would want to know so much about human coronaviruses! I’m glad I found your podcast.

I have been meaning to share a case report that you and listeners may find interesting and finally got the impetus after the TWiV #745’s veterinary discussion. So, here’s more veterinary themed virology to illustrate…

Why we shouldn’t feed COVID sick mink to the dogs

In TWiV #681 the team pondered what would be done with the millions of mink due for culling to reduce the CoV2 variants’ spread in Denmark. In fact, there are already rules and guidelines for animal material disposal in such cases, set out by the OIE and various Food & Agriculture orgs. While these might be considered very wasteful by some (ignored or incorrectly followed maybe by others) this case ( ) demonstrates why they are important.

In brief, carcasses of lambs which had died from Foot and Mouth Disease Virus infection were fed to nearby dogs, the dogs subsequently died of myocardial pathology associated with the FMD virus infection. This is extraordinary as FMD naturally affects cloven hoofed animals. You already knew that viruses can be extra-ordinary, we should just not give them any additional opportunities to prove it.

I would also like the chance to repeat for emphasis the importance of the One Health initiative mentioned by your guest Dr Lamberski. The events of the last year have really emphasised to me the importance of scientific collaboration. We, “brainy-apes” can achieve such incredible things when we collaborate. We can make the world a healthier place – for all creatures.

Thank you Team TWiV for being part of the inspiration and outreach.

From a calm, cool 17oC, spring afternoon in the South of France.


P.S. Why Vincent should never try to castrate any cows. 

With your love of precise wording, I hope you’ll appreciate this wee poke at your choice of words in #745 podcast Prof Racaniello. Just as you can get “grumpy” with people confusing CoV2 with the disease COVID-19, one of my personal peeves is people confounding cows and cattle. I guess people hear about “cow farms” or rather dairy farms and then assume there must be male and female animals there. However, cows are specifically adult, female cattle. So please don’t try to castrate any cows – nor ever try to milk a bull! 

This advice is for your own safety, from your veterinary fans across the globe.

Stay Safe Everyone!

Jennifer writes:

Hi TWiV Team,

I wanted to share some postdoc opportunities that might be of interest to your listeners.

The Precision Vaccines Program at Boston Childrens Hospital/Harvard Medical School are looking for postdoctoral scientists to join their team. The application information is attached and the Nature Careers posting can be found here: 

Appreciate all you and the TWiV team do, particularly this last year!

All the best, Jen (actual virologist by training – reovirus, then HPV)


Jennifer Smith, Ph.D.
Director, ICCB-Longwood Screening Facility,
Lecturer, Department of Immunology
Harvard Medical School,
Boston, MA

April writes:

Hi Vincent,

I was listening to another podcast (scandalous!) And I heard about this path in NY city.  Be sure to look at the photos. It’s on my bucket list!


Michel writes:

Hi Twivers,

Here is a possible listener pick. This was sent to be by a friend and has been very useful in explaining to family members and friends that you really can’t compare the different vaccine efficacies and that possibly waiting for a vaccine with a higher efficacy number rather than taking the first one that is offered to you is not logical.

Why you can’t compare Covid-19 vaccines

The short video 7 minute video is easy to follow, clearly explaining what the vaccine’s “efficacy rate” actually means.  I sure wish the media would focus more on information like this or at least educate themselves properly before creating misleading headlines.

My oldest son, who is an advanced care paramedic, put me on to TWIV last summer. You’ve been a lush tropical island in a sea of confusion and misinformation. While I don’t understand everything you discuss, I faithfully tune in to every one of your TWIV podcasts during my morning walks. Keep up the good work, the banter and yes, you do make a big difference in helping us through these difficult times.


Just a retired former Health and Safety guy (or narc ass Rich would say) who lives in Winnipeg, Manitoba, Canada (where the temperature is -2 C).