Will writes:

Hi Vincent et al,

I’m an electrical engineer from England who enjoys your podcast. 

Daniel Griffin recently commented that it might be good to be sufficient in vitamin D at the beginning of the illness but deficient in it later on.  This made me wonder about drugs like Leflunomide or Methotrexate which people take for rheumatoid arthritis – the immunosuppressant nature of these drugs has led to people being cautioned that they’re at extra risk from CV-19 and to take extra care (very extreme extra care in some cases here) to avoid infection.

However, might it turn out to be the case that such drugs actually reduce the risk of “second week” complications – and thereby reduce the overall risk to their users?  Might it be that they’re actually a “low risk” group rather than a “high risk” one?

I would be very interested if any of you had an opinion on this, and if Daniel has treated people who were existing users of this kind of drug?

Many thanks,


(I realise that you probably get to answer a tiny percentage of the questions you get right now, so I will not bear a grudge if you don’t get to mine – but I might as well ask…)

Mona writes:

Dear TWIV team,

I found your show recently and find it very helpful in understanding many aspects of this awful pandemic.  (Thanks to a review on Slate’s The Gist of 5/8/2020.)  I find discussions of not only virology, but medical updates, statistics and epidemiology, what’s happening globally, the effects on dentistry, the many aspects of testing, vaccines, debunking commonly held myths, and more.  Whoops, now I see a new one!  You’re busy, too!!

I have been concerned about the early what-seems-now-to-have-been over-reliance on ventilators, replaced by more use of the technique of “proning” (but perhaps also ventilation) — because ventilators cause a lot of long-term problems while “proning” is a simpler process causing much less harm and much more good, it seems.  I spoke with my husband who was a Navy Corpsman during time of the Vietnam War: before he went to Vietnam, he worked at a Marine Corps base hospital with patients who had a variety of conditions.   They treated those with pneumonia or other respiratory problems by turning them onto their bellies, turning them 90 degrees and hanging their lower bodies off the sides of the beds.

I was listening to TWiV 617 today when Dr. Griffin was talking about that with, I think, Dr. Rich Condin who asked essentially where the idea for “proning” had come from. The M.D. explained that the ICU doctors had been already doing it for their patients with acute respiratory distress syndrome (ARDS), and that there had been more communication recently between the various doctors in trying to figure out how best to treat their COVID-19 patients–who have severe acute respiratory syndrome (SARS).  I wonder why a treatment known for 50+ years wasn’t used in the first place…  I wonder whether doctors in countries with less money to spend on fancy gadgetry in hospitals use “proning” routinely… I wonder whether I am misunderstanding the situation…


Mona Baumgartel,  Ph.D.

PS: California Gov. Newsom just announced a contact tracing program called California Connected.


Brynn writes:

First, let me be honest about my layperson status and even admit that I took meteorology and oceanography in college trying to avoid the “hard” sciences. Little did I know! 

This is probably a question for Daniel Griffin.  My question is about pre existing conditions and what impact we know or suspect they have on mortality for covid. In trying to decide if sending our children back to school in the fall is safe, my husband and I worry about our son who had apnea at birth (requiring a NICU stay), chronic bronchitis that turned to pneumonia twice and finally a diagnosis of reactive airway disease because doctors didn’t know what to make of his issues. Should parents with kids who already have lung issues be more worried? I feel like there is precious little data on the impact on kids (even with the new Kawasaki like syndrome) and many parents are trying to make big decisions with not enough data. Friends whose children have asthma are just as concerned about whether or not school will be “safe.”

Thank you!


Steve writes:

It was hot news last week here on the BBC that blood clots are a major problem . You guys have been talking of these for some weeks. Now the hot news is T cell count is low in severely effected patients. Is this news to you??. Also its a major problem making 60% alcohol hand sanitiser but you say this virus is a weakling. What level of alcohol would do the job but ignoring other microbes. Love the pod cast and as a non medical person i particularly take on board your commentary and opinions on  government policies and action around the world. I think the world should copy S Korea what country in your opinion has done best for its people.



Beth writes,

In TWiV 617 Sir Joshua Reynolds was quoted from a poster in Vincent’s office. I hadn’t previously heard that one. I thought I’d add two more of my personal favorites on the topic of thought.

“The great enemy of truth is very often not the lie – deliberate, contrived and dishonest – but the myth – persistent, persuasive, and unrealistic. Too often we hold fast to the cliches of our forebears. We subject all facts to a prefabricated set of interpretations. We enjoy the comfort of opinion without the discomfort of thought”. John F. Kennedy

I actually once used that one in a scientific review article on the topic of GMOs.

And below is one that comes to mind given the current political climate in many places about the shutdown, new mask requirements, opening churches, etc. (all the phony first amendment rights protesters)…

People demand freedom of speech as a compensation for the freedom of thought which they seldom use.

Soren Kierkegaard

Carl writes:

Great show.   Helps to remind us that smart people are a blessing to society

Question:  I sterilize my phone, mask and keys when I come back from shopping in my little Chinese UVC box. Why can’t stores and other businesses help with the reopening risk by deploying UV light or Ozone during off hours?

Geoffrey writes:

Here is another quote about what we know and what we do not know. From Donald Rumsfeld:

“…there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don’t know we don’t know.”

Keep up the good work.

– Geoffrey

Paramedic, NYC

Thalia writes: 

Hi all!

I have a question about cross-immunity. (I’m not even sure this is an actual word in English, but I’m translating it from the German word “Kreuzimmunität”).

On his podcast last week, Christian Drosten gave an in-depth account of the strange confluence of factors that led to the 2009 H1N1 outbreak being much less severe than it could have been. He said that according to animal studies that had been conducted on the 2009 “swine flu,” it had the potential to be quite severe in humans. However, due to cross-immunity from previous H1N1 viruses, there were two age groups that had some pre-existing immunity to the 2009 virus. These were people over the age of 52 who had been exposed to a strain of H1N1 that had circulated until 1957; and people over the age of 32 who had been exposed to the so-called “Russian flu,” a strain of H1N1 which re-appeared in 1977. 

Do you think something similar might be going on with SARS-CoV-2, that there might be multiple sources of pre-existing immunity? Drosten has mentioned this possibility several times on his podcast. How would we go about finding out what populations have been exposed to which coronaviruses? Do we have any geographic data on which coronaviruses have circulated in certain parts of the world?

All the best from a very humid Princeton,


P.S. My name is pronounced TH-ahlia, with the TH pronounced like in the word “the.” It’s a Greek name—Thalia is one of the nine Greek muses.

Diane writes:

I love your podcasts, and hope they never end! They are very informative! 

Please address this important issue:  You and your co-hosts have made it clear that the virus behind COVID-19 appears to be from the wild. 

Although I share this belief as well as disgust in the currently circulating conspiracy theories, not all those who entertain the idea that the virus could have come from a Chinese University laboratory believe that it was man-made or man-modified or being studied for malicious intent.

Instead, some imagine a wild virus being studied at the University of Wuhan for legitimate scientific purposes could have accidentally leaped to humans due to poor practices when handling wild animals or the virus/tissue obtained from them.

You have repeatedly encouraged more study of wild viruses, however, if the problem was indeed lack of proper care or control during laboratory/field work, then isn’t it possible that more widespread study could exacerbate the problem, making similar pandemics even more likely?

Thank you for your input on this, and thank you again for your podcasts.

Diane M.

Granada Hills, CA

Kevin writes:

Dear TWIV Team,

After your insightful discussions about singing in the past few episodes I thought you might be interested in hearing about a sars-cov2 cluster detected in Germany near Frankfurt.

A religious service, where the attendees were singing without face masks has been found to be at the center of a cluster of 107 confirmed cases.

The organizers claim to have complied with the required social distancing regulations but unfortunately didn’t listen to twiv.

Keep up the good work,



from Zürich, CH

where it’s sunny and 20°C.


German article:


English article that summarizes it but leaves out the part about

singing (I searched a little but couldn’t find any English articles

that mention singing):



Dr-Ing. Kevin Kilgour

Google Research and Machine Intelligence

Brandschenkestrasse 110, 8002 Zurich, Switzerland

Anthony writes:

Crowd waiting to be vaccinated against smallpox at the Department of Health building in NYC. April, 1947

Photo: Al Ravenna  

Crowd waiting to be vaccinated against smallpox at the Department of Health building in NYC. April, 1947Photo: Al Ravenna

Posted by Tom Bennett on Tuesday, May 19, 2020


Richard writes:

Hey Crew!

I eagerly await every episode after my discovery of you in January. Thank you so much for what you do and for helping me to be informed on a subject matter that goes well beyond my basic understanding of things.

You’ve mentioned the comet like trail behind runners and cyclists, and ways of going about playing tennis…but I think swimming adds a handful of further complications I’d love for you to discuss! Public pools are often in enclosed rooms, when you’re breathing you’re getting a little water in your mouth and probably spitting some of it back into the air and pool, and you’re in pretty close proximity with other swimmers even if you try to keep your distance.

My question is: is it safe to use a public swimming pool? I imagine the acid/chlorine in the water handles whatever makes it there (assuming it’s not in a thick enough amount of mucus to stay present for a while), but what about all the aerosolized bits? I imagine there’s some chlorine in the air but would love some peace of mind beyond the CDC saying that it’s safe. https://www.cdc.gov/healthywater/swimming/index.html

Thank you all so much again and thank you in advance if you make it to my question,


Marybeth writes:

Hi guys,  I love your show. It’s the only thing keeping me sane. 

I received an email this week from an MD ( Dr. Kelly Brogan) basically stating that the media is lying about covid. She shared the following site and I’d like your thoughts. I feel like I have cancer just from looking at this site. I am quickly losing hope that our species can overcome the conspiracies and survive. 

Thanks for all you do!


Katherine writes:

Good Evening,

I am in Columbia, MO.  I haven’t found a weather app that is accurate enough to give the exact temperature so I will just say it is hot and humid.  Mosquitoes are right around the corner. 

I am a 35yo female with a normal BMI. My LDL is a little high and I smoke a pack a day and wheeze if I breathe out real fast but no other huge health concerns.  (My doc said I’m too young for COPD and she thinks mild asthma triggered by the smoke.)  Again, no huge health concerns.  I was, however, diagnosed with obsessive compulsive disorder as a teenager.

I have not been in a public building since mid-March other than going to the hospital last week for a mammogram.  I had anxiety the whole time.  I seriously doubt the waiting room was positively pressurized and there was not a single window open.   The staff were supposed to be wearing masks but about 20% of them weren’t.  One elderly patient had her mask off and was coughing a substantial amount.  I moved 40 feet away from her.  

I am fortunate enough to be able to work from home.  I have my groceries contactlessly delivered outside my door and I wipe them off with a disinfectant wipe before putting them away (including refrigerated and frozen foods.)  When I order takeout I make sure the establishment will let me pay and tip over the phone without having to sign and will drop the food off in the trunk of my car when I pull up outside.

My boyfriend of 3.5 years and I live apart, mainly for the cats.  (Each cat wants to be an only child.)  We take turns staying at each other’s apartment. During the stay at home order the sporting goods store he works for closed down.  I made sure he followed all of the same precautions I did in regards to not being within 6 feet of another human being outdoors and not being in a building in which a human has breathed in the last few hours.

 Our stay-at-home order lifted a couple weeks ago.  He has started working again and I refuse to be around him other than outdoors and several feet apart.  He is exposed to customers and his coworkers.  We do not know when we will get to see each other again.  The only solutions I see are a) stay-at-home order reissued b) vaccine (I will refuse to take one produced at warp speed.  I want one that has gone through the same process any FDA approved vaccine would have had to go through before 2020.) or c) tests

I have two questions:

1.  Do you think I am being unreasonable with my precautions?  (And yes…I know smoking has a higher probability of long term health effects than this….but that’s a tangent that has already been well-addressed)

2.  When do you hypothesize reliable (say maybe > 95% sensitivity and > 90% specificity ) at-home rapid result testing will be available for purchase by the public?  

Thanks in advance,

The unspoken Q for Carolyn Hax or Philip Galanes – what to do for this relationship

Joyce writes:

Hello –

It is so lovely to know that your podcast has existed in the world for all these years, and to be able to flit in now when it’s relevant to my life.  Thank you for doing this, and for going to the extra effort to be accessible to non-scientists.  I am a member of a totally different niche nerd community, the font design world, and so I know how much extra work it is to be accessible.  

As an aside, you might not think fonts are so hard  to understand but trust me, it’s essentially a form of industrial engineering that is licensed intellectual property.  We have computer engineering specialists, forensic historians, designers (who have to specialize in optics and calculus), and software licensing experts (that’s my speciality) and more.  So, thank you soooo much.

I have a few questions I hope you will do me the honor of answering on air:

1.  Did I understand from your May 23rd episode that all Parkinson’s cases may be triggered (if not directly caused) by colds?  This is especially fascinating to me because my grandmother was diagnosed with what they at the time called “Pseudo-Parkinson’s”.  She was eight years old during the 1918 flu and showed signs of Parkinson’s in her late twenties or early 30s (family stories are a little vague).  I believe she was in an early L-Dopa test group and that when she died in her early 80s she had one of the longests known cases of the disease.  Of course, some of this may be inflated by my father and so I’m always curious to know more.  He said that the fact of her Parkinson’s being pseudo was why she lived so long with it.  But, if all Parkinson’s patients show signs of a viral trigger would her’s even still be considered Pseudo?  On a personal level, I was told I didn’t need to worry about getting Parkinson’s because the way she got it was unusual, but if it wasn’t does that mean that her descendants might be at risk of the same thing happening from a different virus? Does vulnerability to viral triggers run in families?

2.  I’ve only listened to a few episodes so please forgive me if you’ve already answered this one.  I have heard your team casually say “in the fall” with regards to a second wave.  However, I’ve never heard you say definitively that Covid Sars 2 is seasonal (and I’ve heard from other sources that we just don’t know).  The easiest way for me to rationalize both facts is that even if it isn’t seasonal the time required to ramp back up to a wave would get us into the fall.  Is that correct?  If so, what are best practices for medium risk individuals during the summer?  I’m defining this group as middle aged with no or few comorbidities, in non-essential fields like font design, who do not live with high risk persons.

I want to make sure I am clear about my grandmother so that my letter doesn’t have some sort of red herring in it.  The story as told to me when I was young is specifically that doctors said she developed the Pseudo-Parkinson’s as a side effect of the 1918 Flu.  I’m 43 and I grew up hearing this story so it way predates any zeitgeist about flu pandemics.  

The kicker was always “and she never got sick”.  The implication was that it was somehow more dangerous to be asymptomatic. Even as a kid that struck me as wrong because I knew people with Post-Polio Syndrome.  It wasn’t until recently that it occured to me to wonder if she her self reporting about not getting sick was even accurate.  She had bad hay fever as an adult (I don’t know if she had it as a kid) and there’s always the chance they mistook flu for allergies.  There’s no one left for me to ask but even if there was how would they know? I’m assuming the same thing is an issue now.  If I were to get sick but not have a fever or loss of taste I might not remember the mild illness a month later when asked.

Warm regards,


Sheldon writes:

Hello the TWIV Crew:

There are an awful lot of vaccine candidates out there.  Some of them are an addition to genetically modified viruses.

Having read about the CANSINO vaccine results, why has the Ad5 virus been used rather than one that people are less likely to have immunity to, such as the Ad26 virus or going further to gorilla Ad viruses.

The people involved certainly knew of issues with Ad5, so why was this used. Could it be difficulty in using other strains or non-human strains in growing them?

And what do you think of the oral (pill) vaccines being developed.


John writes:

Hi, TWiVers.

I just* wanted to point out that Rich was slightly wrong in TWiV 616 when he explained “upstaging”, getting the position exactly backwards.  If Alice is angry that Bob has “upstaged” her, it means that HE was standing upstage of HER, not the other way around.

The problem is that in order for her to face him, she must turn further away from the audience, which makes it more difficult for her to speak or emote towards them.  He, getting to face the audience, draws more of their attention, whence the popular usage of the term.



David writes:

Wimberley, TX 90*F, 32.2C, 305.37K,

I became a fast fam of TWiV (et al) after I heard about a “novel pneumonia-like illness spreading in Wuhan, China” in December. I am neither a student, teacher, researcher, or physician, just a potential viral host so I never expected to be able to contribute anything to the program’s content, but here’s my chance.

In episode #615 Rich Condit explained the vernacular use of “upstaged” in a way that suggested it was caused by one actor coming between another actor and the audience. My ears perked up because I knew the truth was much more subtle and nefarious. It isn’t that one actor blocks another actor from the audience’s view, that would be much too obvious. “Upstaging” is a sly way of manipulating another actor to turn his own back on the audience. When two actors are engaged in a dialogue, one actor needs only move upstage (toward the back of the stage) by a few steps and the other actor is forced to turn upstage to address him. This puts the audience’s primary focus on the upstage actor because the downstage actor’s head is turned, thus making the upstage actor appear more important.

There, I may not have solved the mystery of furin cleavage in SARS-CoV-2, but I have done my best to maintain the integrity of  “Scene-stealing Science” on your wonderful program.

Thanks for all you do and all you have done to share the world of virology with its intended victims.

Bono malum superate.



Aaron writes:

TWiV team,

I never thought the day would come when I could chime in and offer a comment that adds something. I’ve been listening for a few years now from St. Paul Minnesota (70F and cloudy). I’m JUST lab technician for a good company by day and actor by night. 

When I heard Dr. Condit provide his definition of “upstaging” I was in my car and almost immediately pulled over to send this e-mail. Not out of excitement to correct you, but out of excitement that I can add something constructive to the conversation. In all of my experience as a stage actor ”Upstaging” has meant the opposite of what Dr. Condit described. Upstaging someone is where during a scene when you are talking with another actor, you move upstage of them (further away from the audience). This forces them to then turn towards you to continue the conversation and turn their back to the audience. This draws all the attention, almost immediately, to the person furthest upstage. Furthermore, In the theater you NEVER turn your back to the audience because it highly reduced their ability to hear anything you’re saying. If you get two actors who are competitive enough they will upstage each other until their scene is essentially being played against the back wall. 

Love everything about this show, and all the work you’re doing. Keep it up!



Mark writes:

Haiku for today’s episode

Dear Grumpy TWiVers,

We social distance

Vinny and the gang do too

To stop the ‘rona


Christian writes:

Hi Twivs

Once again, thank you so much for providing us with facts in an era of poppycock.

Could you please give the answer of the almost Shakespearian question:

To mask, or not to mask

Apparently Taiwan and South Korea have kept the numbers of infected extremely low by using them, but here in Denmark the authorities still claim that there is no evidence of the benefit of using them. 

What’s the truth ?


Best Regards/Med venlig hilsen


Anonymous writes:

Dear TWiV,

This is a love letter, but its writer is also a bit grumpy. First, thank you so much for the show. I tune in to every episode from my apartment in quarantined Moscow, and consider it THE thing that has kept me grounded during the insanity of the pandemic. What I really admire most about the podcast is that you strive for accuracy and emphasize the scientific significance of nuance. In keeping with this, I wanted to point out a few inaccuracies in your discussion of coronavirus in Russia (TWiV 614), as well as draw your attention to a few critical nuances. First, no one in Russia is suggesting that all the Covid-19 cases have been in Moscow. It is true that Moscow, like New York City, has been the epicenter of the country’s epidemic. No wonder, considering that the city likely has an actual population of 15 million people. (Not quite Mumbai, but a megapolis all the same). The city government has also rolled out a broad range testing scheme (asymptomatic individuals have been able to access tests for a small fee since March), which is free for anyone showing symptoms. This no doubt has contributed to the city’s case counts. Most other regions in Russia have also been affected by Covid-19, although (at least officially) to a lesser degree than Moscow. (Access to testing could be one factor here, as it varies depending on regional governance and epidemic status.) Some notable areas outside Moscow that have suffered major outbreaks include the Komi Republic (See the article on the situation there in the New York Times), Dagestan in the southeast, and Niznynovgorod (formally the closed city of Gorky, know for the Soviet “AMO” automobile factory, where incidentally many American leftists came to work in the 1930s.) The official statistics by region are posted every morning in the press, and English language coverage can be found in The Moscow Times: 


Russia has a creaky system of free, universal healthcare, which despite its age and infirmities has proven advantageous in a pandemic situation. Moscow’s designated Covid hospitals during the worst days (~6,000 officially confirmed cases/day) operated at full capacity, but still managed to accept and treat patients. (Patients with non-Covid ailments are sent to designated “clean” hospitals.)

I hope this synopsis is interesting and helpful. 

From and one of your biggest Moscow-based fans. Keep up the awesome work!

signed, Anonymous

Nick writes:

Vincent – I think you and your team might enjoy these two videos that related to the pandemic.  Perhaps not as clever as the poem from around Episode 601 or 602 from one of your students but nonetheless entertaining. Thanks for all that you do! Nick


Nick Clark

Clark & Clark

Julia writes:

Hi TWiV Team, 

Special hello to Professor Racaniello – I was a student in his spring 2019 virology course and have been a TWiV listener since around February 2019. Greetings from Philadelphia where it is currently 68F/20C. 

During shelter in place, each time I have walked around my neighborhood, I have seen at least one dead bird on the sidewalk. Prior to the stay-at-home order, I walked around my neighborhood far more frequently and never saw any dead birds. (I’ve considered that maybe I’m being more observant but I am skeptical given the extra things to think about on walks/runs like making sure my mask doesn’t fall down and trying to keep 6ft from others.) 

Do you think this could be related to SARS-Cov2 infection? Should we be worried about birds as a reservoir of SARS-Cov2? 

Thanks in advance! 

P.S. Unfortunately I don’t know enough about birds to tell you which type(s) I’ve seen.