Bill writes:

Dear Vincent and Daniel,

Here  is a link to one recent paper:

Maybe Dr. Griffin could talk about this from his perspective.  

Thanks for this great podcast!


Julie writes:

Hello all,

I heard it mentioned on a recent TWIV podcast that rates of Covid in NY among pediatricians are lower than the general population? Could you give me more information about this?

Great podcast by the way! I listen frequently and often wonder if I missed my calling as a virologist. I’m learning so much.

Julie Thompson, MD
Perioperative Medicine
Contra Costa Regional Medical Center
Martinez, CA

Charles writes:

Hello TWiVers and very special guest Dr. Daniel Griffin;

I would like to ask some questions about tocilizumab and one about remdesivir.

Remdesivir first.  Seems like all of the reports I have heard say antivirals would need to be given early, very early according to some (see TWiV 622 for example).  I understand that without very good TETRIS giving remdesivir as early as necessary is hard.  So the question is, do we have enough TETRIS to do a study where remdesivir is given as soon as a person tests positive.  I am thinking about meat packing facilities, health care facilities and some factories where testing is frequent and I am guessing they are using an antigen test. For the study, if the antigen test does not give very many false positives, that would work, not that it would keep the workforce safe.

Now tocilizumab.  Please keep in mind, I am an IT person, so please correct any mistakes I have made in this post.  Tocilizumab is long acting (half life of 21.5 days) and that seems to be a problem.  Either it can lead to a post SARS-COV-2 infection, or IL-6 all of a sudden has a lot of cells with an open IL-6 receptor and that leads to a secondary cytokine storm.  Would siltuximab help with the secondary cytokine storm, because the current IL-6 would still be incapable of binding to the receptors and it would take time for new IL-6 to get to the lungs?  Siltuximab has a half life of about 20.6 days which is close to the same as tocilizumab, so I don’t think it would make much if any difference in the secondary infections.  Now I am going way off into the weeds and may make a fool of myself.  Ozanimod also calms the adaptive immune system, but does it calm the parts that cause the cytokine storm that is a part of COVID-19?  If so, ozanimod has a half life of under a day, but has an active metabolite with a much longer half life of about 11 days.  So would ozanimod be worth trying?  Deeper into the weeds and full disclosure, I own shares of Arena the maker of estrasimod.  If ozanimod is worth trying would the experimental estrasimod be an even better candidate with a half life of around 1.5 days?




In The Pipeline blog:





Antigen test:

Khadijah writes:

Um so we are not going to talk about race

Dear TWIV,

I’ve been a longtime listener time-pre-plague-but have doubled down in the midst of the pandemic to the point where I’d have nightmares of waking up in the ICU screaming at the podiatrist “listen to TWIV, first 20 minutes Daniel Griffin!” I’ve launched my own podcast, We Be Imagining examining the intersection of surveillance/policing, COVID19, tech, race and gender. I was overjoyed that our pod was going to be aggregated on the Columbia podcast website alongside TWIV but our arrival has been bittersweet.

The TWIV suite of podcasts collective silence on the racially disproportionate rate of COVID-19 mortality, the racially differentiated police enforcement of social distancing and global protests demanding justice for George Floyd who recovered from COVID only to be brutally murdered by the police is deafening. The decision to open episode #624 with a White savior call to donate to an African charity as if there are not Black people at your doorstep demanding a reckoning is shocking and words cannot express the degree to which I’m heartbroken by my favorite podcasts’ refusal to acknowledge Black Lives Matter. I have to say by Daniel’s silence even more so since as a clinician I imagine he’s currently attending meetings where racial differences in the impact of COVID are being discussed. This is why we’re afraid to go to the doctor and drop out of STEM programs!

Even virology is situated into a social political context, we cannot understand the spread of COVID19 outside of the exponentially higher rates of infection in Rikers Island relative to the rest of the NYC area. I have always appreciated your commitment to science communication but you are not only alienating your audience by refusing to address the intersection of race with COVID 19 but those who stay are receiving a distorted view via this omission. 

I suggest you invite a Black epidemiologist on your show and someone like my good friend Dorothy Roberts who examines bioethics from a sociological lens. I’d also be willing to collaborate on an episode with you if that’s something you may be interested in. 

Either way I’ve really enjoyed so much of your show and am hoping that you will remediate this glaring silence with more than a solidarity statement and work to integrate critical race theory into the show by inviting more Black and of color guests.


Margaret writes:

Dear TWiV,

I know you like to keep politics out of the discussion and let the science speak for itself. At the same time, I listened with a sense of pride in my TWiV friends (and yes, I know you’ve never met me) as you talked back to the suggestion that Black people are more likely to be infected with SARS-2 due to a vitamin D deficiency. On TWiV 606, one-by-one, you took down that specious argument.

Here is an interesting new development, a “strike” tomorrow, June 10, to “shut down STEM” for a day of reflection. Everyone is doing their part:

I’m doubting very much you can take this up on the show, but writing because I feel you are in accord. I love Kathy’s Spindler’s “diverse teams,” linked from the TWiV site, Vincent’s devoting a lecture to the naming and recognition of Henrietta Lacks, and Rich and Alan’s articulate explanation of why phenotype does not determine predisposition to disease in the “black and ethic community” (on TWiV 606).

Then there’s the why of the lack of diversity in STEM. I’ve been thinking about it quite a lot and feel it’s very hard in our country to get into STEM without a close mentor or family member to talk to. The dinner table is the thing. TWiV is a sort of dinner table conversation, but maybe a bit more diversity is in order on the guest list?

With admiration, as always,


Keith writes:

Your comments on this would be greatly appreciated.  Love the show. Thank you


Owen writes:

Dear TWIV team;

I listen to your podcast on my way to the hospital where I work here in Melbourne Australia. You asked for a Haiku and I am happy to oblige.


Today I trembled
at the ways I touched, not yours
but my lips, eyes, nose.

Yours in gratitude


Tony writes:

Like thousands of others I found your videos and podcasts when searching for information on COVID-19. Other than being infected by viruses during my life (like everyone else), I have expert knowledge of them. I keep reading on Dutch news sites about people supposedly catching the virus from a mink ( ) . They also repeatedly mention cats though I haven’t heard much about cats recently in other countries. What are your thoughts on these reports? 


Tony Fisher (maker of the world’s largest Rubik’s Cube) 

Evert writes:

Dear Professor Racaniello,

A few weeks ago I discovered your podcasts on youtube and then the whole series of TWIV podcasts in Google podcast. First of all, I would like to thank you and your team for these podcasts that contain a wealth of evidence-based medicine data on viral infections and associated disease. I follow the podcasts on covid-19 with great interest. I am a veterinary pathologist (DVM, PhD, dipl ECVP) and would like to draw some attention to comparative pathological aspects of coronavirus infections in animals. More specifically, the role of sars-cov-2 in vascular/endothelial pathology is not unique to this virus. In veterinary medicine, we are aware of a corona virus which causes severe disease due to vasculitis and/or increased vascular leakage. In the cat and other felines, feline corona virus may cause severe and fatal disease, which essentially is a result of Antigen-Antibody complexes and associated vasculitis. This disease in felines is called feline infectious peritonitis, abbreviated as FIP and is caused by a coronavirus. There are 2 presentations of FIP: the form characterized by granulomatous inflammation in the thoracic and abdominal cavity and the exudative form characterized by fibrinous peritionitis and pleuritis. Central to the pathogenesis of both presentations is the occurrence of vasculitis due to antigen-antibody depositions in vessel walls (type 3 hypersensitivity reactions). Sars-cov-2 is therefore not unique amongst the large group of corona viruses that may cause vasculitis.

In addition to this, I would like to draw your attention to diagnosed sars-cov2 infections and covid-19 like disease in farmed mink in The Netherlands. These animals appear to have been infected by farm workers who have shown to be infected by sars-cov2. The important question now arises, of course, whether these mink can then again be a source of infection for humans.

I would encourage you and your team to use this information in your excellent podcast on the subject.

 Kind regards,

 Evert van Garderen DVM, PhD, Dipl ECVP (diplomate of the european college of veterinary pathologists).

Mary writes:

A mink may have infected a second Dutch worker with coronavirus, agriculture minister says


Keep up the great work TWiV !


Below are emails about the WHO statements on transmission by asymptomatic people (symptoms = what you can feel; signs = what others measure)

This is not the first time WHO has said spread by asymptomatic patients is rare. I’ve seen it before: from the joint WHO-China report on CoV disease, issued Feb 24:

“Asymptomatic infection has been reported, but the majority of the relatively rare cases who are asymptomatic on the date of identification/report went on to develop disease. The proportion of truly asymptomatic infections is unclear but appears to be relatively rare and does not appear to be a major driver of transmission.”

But they never shared the data for this statement.

For more see axios article at end of email thread

Erin writes:

Hello Twiv experts!

Your show has kept me sane for weeks.  Im forever grateful (and so is my husband) 😂

Reading about this update from WHO leaves me confused.  Did we just jump from ‘people are most infectious prior to showing symptoms‘ to presymptomatic superspreaders to full circle that we look for symptoms first?   I don’t feel like this fits with what I understood. 

Can you help clarify what we actually do know now?  Thank you so much! 


Erin (a mom in Texas)

Ana writes:

Dear TWIV hosts – Thank you for all you are doing, educating us on viruses and now in particular, SARS-CoV-2. I love hearing your analysis of current research findings and also hearing about Dr. Daniel Griffin’s clinical experiences on the front lines. I have a question – I saw this article today:

The WHO is stating that asymptomatic patients are not driving the spread of SARS-CoV-2, but I thought that I heard on your show and from other sources that asymptomatic carriers were a huge driver of viral spread. The WHO hasn’t released their public data on this yet (that I’m aware of). But I wanted to get your take on this topic and what we currently know about asymptomatic SARS-CoV-2 carriers. Thanks in advance!



Ana Misic, PhD

Field Applications Scientist

Northeast Mid District

Illumina, Inc.

Sam writes:

Thank you. You are the only one’s I believe. Not the CDC, any other scientists related to the federal government and not WHO.  Just university scientists.  

Please comment on your next podcast about WHO saying asymptomatic spread is rare.

Thank you. 


Salvatore (Sam)

Mikhail writes:

Hello from London (21 degrees centigrade, cloudy with chance of meatballs).

I’m a Investment Analyst who has gotten hooked on your podcast as one of the best places to get up-to-date and insightful analysis of the pandemic well before the rest of the world. In my line of work this type of raw intelligence is vital, so thank you so much for all you’re doing!

I had a quick question – feel free to ignore if it’s too basic/silly to respond to – but I’ve seen a few stories coming out of the UK about roughly 40% of positive test results are asymptomatic, and was wondering how to reconcile that with the antibody studies that show only around a 10% of the overall population have been infected.

If 40% of people infected don’t show symptoms, does that mean the fatality rate is much higher than we thought? How do I reconcile the serology/antibody prevalence stats (showing ~10% prevalence) and the idea that 40% of people were infected but didn’t show symptoms?


PS I just heard this on the prime UK radio news show (Today – BBC Radio 4) – – thanks to your show I knew it was rubbish – but what fresh hell is this? Wrong on so many levels!


[vr re parking lot story: the TMRCA is Oct-Nov, not likely there was extensive spread at that time. And if the fish market lot also increased, that just means there were more cars a year later!]

Judy writes:

Hello TWIV gang!

The most recent WHO announcement is SUPER confusing:


“From the data we have, it still seems to be rare that an asymptomatic person actually transmits onward to a secondary individual,” Dr. Maria Van Kerkhove, head of WHO’s emerging diseases and zoonosis unit, said at a news briefing from the United Nations agency’s Geneva headquarters. “It’s very rare.”  

Government responses should focus on detecting and isolating infected people with symptoms, and tracking anyone who might have come into contact with them, Van Kerkhove said. She acknowledged that some studies have indicated asymptomatic or presymptomatic spread in nursing homes and in household settings.


Early on post infection, who knows if someone will be asymptomatic, or go on to have mild or severe symptoms. There seems to be clear evidence of super spreading events from pre-symptomatic individuals (the choir case and the Singapore Church case ).

Because of these cases, it seems to be me that knowing that asymptomatic individuals rarely transmit onwards is nice to know but of little practical use. In my local community, people are using this announcement as an excuse to stop using masks which I think is unwise.

From an epidemiological perspective, why would WHO make this announcement? Where is the data to back it up? 



PS You guys are awesome!!! You are THE go to source for technical but not too technical questions regarding the virus. Keep up the good work.

Raches writes:

Dear TWIV Team, 

I want to thank you for the continued dedication of COVID-19 related information. I work for Bharat Biotech, which is a vaccine manufacturing company based in India. We currently supply close to 750 million doses of vaccine per year. 

Currently, I am the project lead for three Covid-19 vaccine projects. Two of our projects are in collaboration with Dr. Kawaoka at the University of Wisconsin using the H3N2 influenza backbone. Another is with Dr. Mathias Schnell (Thomas Jefferson University) using an inactivated rabies vector. 

The third vaccine is a conventional whole Virion inactivated vaccine that was isolated from a covid infected patient. 

COVID-19 research and vaccine development are extremely confusing with so much literature out there, but after hearing your podcast, It makes it easier to cut out the noise. 

I am applying to Columbia business school next year and look forward to meeting you all after our vaccines get licensed! 

Thank you again for all your efforts, and stay safe!