Bill writes:

Hello Everyone,

As far as Melville-inspired cat names go, I’ve always been partial to “Bartleby.” For much like the titular character of Melville’s Bartleby, the Scrivner, most cats would “prefer not to” do much that’s asked of them.

Thank you for everything you do to keep your listeners informed.

“Just” a humanities major,


Deepa writes:

Dear Twiv: it’s sunny, windy and 69 degrees in Hillsborough CA. You spoke about FIP on podcast 626. I was reminded about this article

I read in the Atlantic on black market antivirals for FIP. Every molecule has a story! 

I am an immuno-parasitologist and chemokine immunologist turned banker turned investor, who is learning a lot about virology from your excellent podcast.



Deepa Pakianathan, Ph.D.

Delphi Ventures

Mason writes:


On one of your recent podcasts, you briefly mentioned Feline Infectious Peritonitis (FIP). According to an article in The Atlantic published in early May  (, cat owners have been successfully treating FIP with black-market compound GS-441524, a Gilead-patented compound very similar to Remdesivir. I’m  just bringing this to your attention as you expressed some interest in discussing FIP.  The Atlantic article is quite interesting, albeit clearly playing up the potential of antivirals to human coronaviruses more than I believe is warranted.



Guilherme writes:

Hello Twiv’s crew. I heard you making some speculations about Brazil and I’d like to clarify some things.

  1. Although Brazil’s health system is not state of the art as some more developed countries, it’s not that bad. It’s based on the British system, being free and universal.
  2. The real reason Brazil’s doing so bad is political. I know you avoid the subject as much as you can, but it’s impossible to analyse Brazil’s situation without politics. Our president, Jair Bolsonaro, denies science, doesn’t care about the 40k+ deaths and has put all his chips on hydroxicloroquine as a viable cure. The governors on the other hand, tried to make lockdowns, but we’ve neve had more  than 60% people at home and due to the lack of federal help, people started pressuring for reopening the commerce, even though the cases never stopped rising.
  3. About the vaccine, we do have the ability to make it through Fiocruz and Butatã Institute. Also, due to how bad we’re doing, we’ve become the perfect testing place. So Oxford University and a Chinese Company called Sinovac are starting to make phase III tests here. 2k people for Oxford’s test and 9k for Sinovac’s test. In exchange, they’ll give us the means to produce the vaccine in case things go well.

There’re many more political reasons things are going bad. Racial tension is also escalating, we have the most lethal police in the world (even more than China and India, that have a much bigger population than us). But if I keep going I’d have an entire episode reading this and it still would not be enough.

Also, we have a very good virologist called Atila Iamarino that would make a great addition to your podcast and could give you a better overview about Brazil.

PS: Also, in Brazil, we avoid the word “favela” nowadays, preferring the word “Comunidades” (communities)



Jason writes:

Dear TWiV Team,

I’m writing from moderately overcast Berkeley, CA where it is currently 22degC   (295.15 Kelvin).

On TWiV 626, you mentioned the Politico article headlined “Suddenly Social Justice matters more than Social Distance.”  With regards to protests, Brianne Barker also mentioned  we can have “socially distant mask wearing protests.”

Both statements seem to confound two very different concepts: social *distance* and social *distancing.* 

( vs.

It is unfortunate that the request for physical separation between individuals to curb the spread of infection has been termed “social distancing” or “socially distant”.  *Social distance* is a concept within social sciences describing a sociological phenomenon. The term ‘social distance’ is many decades old and refers to the separation of groups within a society by class, race and ethnicity, and other groupings.

Prejudice and racism are a manifestation of social distance. Social distance does not necessarily mean physical separation; there is considerable *social* distance between the guests at a luxury hotel and the staff who clean rooms can be physically very, very close, but are separated by stark societal divides.  There is considerable social distance between immigrant taxi drivers and wealth individuals riding in the back seat, only a couple of feet away.  The sociology 101 example of ‘social distance’ is the caste system in India, ingrained rules meant to prevent intermixing by inherited social status.

Social justice is in no ways something that social distance opposes.  Social distancing is poorly and unfortunately named because it does not aim to increase social distance. It aims to increase *physical* distance regardless of the social distinctions. Why the term social distancing was chosen rather than the more accurate term ‘physical distance’ (a term that I have heard Dr. Fauci use more often of late) is beyond me.  Protests against systemic and institutional racism should not be *socially* distant nor should it in any way encourage greater *social distance*. Part of the goals of such protests is to recognize the social barriers that currently separate us and to move towards removing them.  Risk of COVID19 may require that protests involve more physical distance; the distance does not and should not involve erecting social barriers.

I apologize for sounding pedantic, but I would hope that as scientists, you would appreciate the value in accurate definitions and the danger in allowing buzzwords to obscure purpose and intent.  *Social* distancing fails this, both as it needlessly redefines *physical* distance as something else and as it needlessly intersects with a concept with a rich history in academic studies. Please, I implore you to stop needlessly tossing “socially” in front of distant when you mean physically distant.

We can maintain physical distance while breaking down the barriers of social distance that are in direct opposition to social justice.


Dave writes:

Dear TWiV,

Physical v Social Distancing

It’s probably about time to get pedantic about these terms.

1) Everyone seems to use “social distancing” to describe a six feet apart rule at a place like the grocery store were you may or may not have a social connection with another person.

2) “Physical distancing” is probably a better term for the above. But it seems people are good right now to not physically distance with those who they are most “socially” connected with.

3) Impatience and lack of understanding of this element of human nature isn’t going to help as we forestall while waiting for effective therapies or vaccines. Nothing that I have seen suggests that on average that we are much better off as a nation than we were a month or so ago.


Zach writes:

Hello TWIV crew, I’m a nurse practitioner in Yakima, WA where our county sadly has the highest per capita rate of lab confirmed infections on the west coast.  Thank you for the informative podcast over the past decade which I admittedly took a sabbatical from for several years until the recent pandemic.  In episode 626 you mention antigen testing and I just wanted to forward this along.  Our clinic is going to start using an antigen test this week from the Quidel corporation, Sofia 2 SARS Antigen test.  Results are currently taking up to 4 days with our current lab so I’m excited about the possibility of 15 minute results. Just hoping that the results will be reliable.


Amy writes:

In a recent TWIV, the topic of who would get the first production of the SARS-CoV-2 vaccine.  Are there organizations working to push for fair and data driven vaccine distribution?  Who could set that?  

Thank you for all you do, I feel more confident because I can listen to you. 

Best regards, 


Below: Is Russia the new Sweden?

Angelina writes:

Dear TWiV,

I wanted to say thank you for reading my comments about the Covid-19 situation in Russia on the podcast. It was really great to hear! You are absolutely right too that for the longest time the Hopkins’ dashboard had one single dot on Russia, making it impossible to understand the extent of the spread in the country. I noticed that they only recently changed this, so that the epidemic information is now posted for different cities. Maybe they did it in response to your comments on TWiV? I hope so, as it was high time! 

I also forwarded the episode with Konstantin Chumakov to a history of science network, where it was appreciated and enjoyed. Now if only I can come up with a way to make TWiV required listening for the students in my undergraduate art history courses…I’m sure there is a way, with a little creativity.

Thanks again! 

All best,

Angelina Lucento


Dr. Angelina Lucento

Assistant Professor of History and Art History

School of History

National Research University-Higher School of Economics


Worried about Russia writes:

Dear TWiV,

I’m writing to you from Saint Petersburg, Russia, and it’s +13°C and cloudy here now (the time is past midnight, June 6th).

Having some natural science background (BSc in physics, don’t work in science though), I started listening to your show in late January and now I have listened to all the COVID-related episodes up to June 3th not just of TWiV, but also TWiEVO and Immune (the process is very time-consuming, but on the other hand I’ve improved my English listening skill a lot). I have been retelling the facts about the origin of the virus and explaining impossibility of its origin from a lab to my acquaintances for months, and also advertising your podcast in my group chats.

Some nostalgia (you might skip that part in the episode): in early March I wanted to write a letter to TWiV complaining about people not washing their hands in public toilets, but I procrastinated for less than a week, then WHO declared a pandemic, and I quickly realised that you have more important matters to discuss.

I would like to reply to the anonymous Muscovite whose letter from around May 19th you read at Episode 621. While there’s no untruth in the letter, the author in my opinion missed “a few critical nuances”.

Foreigners visiting Moscow often think the rest of Russia is more or less similar to the capital. However, Russia is better described as two countries in one: Moscow and all the rest (for brevity I’ll call the latter “Russia proper”), there’s even a Russian literally stating that Moscow is not Russia (Москва не Россия). The difference between Moscow and the worse half of Russia proper is not something like NY vs. Mississippi but rather NY vs. Puerto-Rico.

Moscow indeed has “a broad range testing scheme”, but Russia proper has a shortage of tests (and a turnaround time often around a week). Moreover, even though Saint Petersburg is the largest city in Russia proper (5M ppl) with an impressive official number of 22k people tested on June 4th, a significant portion, possibly even a majority of test results conducted by state labs just never arrive: swabs are sent to a lab and then there’s no response. It looks very much like authorities artificially inflate the number of tests they report. 

Regarding the statistics of confirmed cases, thanks to math there can be no doubt that it is intentionally tampered with. The best example is so-called “Krasnodar Kray plateau”. Starting from May 4th, regional authorities reported these numbers of new diagnoses: 96, 97, 97, 99, 99, 98, 99, 98, 99, 96, 97, 99. Even a schoolboy scoring D in math would understand that these numbers are shamelessly faked! And this is not just one region, up to a half of Russia proper has similar artificially stable numbers (albeit not around 99), including my own city. A less obvious example: four times between April 30th and May 24th the four-digit number of new cases ended on 99. Listeners of TWiV can try to estimate the probability of this being random incidence themselves, but it’s well below 1%.

A lot has been written in Western press about the statistics of deaths. Despite WHO recommending otherwise (TWiV listeners probably remember about blood clots!), Russian Ministry of Health basically instructed forensic pathologists to not count a death as caused by COVID-19 if an immediate cause of death allows to ascribe the death to something like a stroke, a heart attack or a flare-up of a chronic disease. It is not an exaggeration to say that deaths are systematically covered up in Russia, for more details see (as a side note: while The Moscow Times is a great newspaper which I can recommend as a reliable source, as its name suggests, they lack reporters outside of Moscow, and this Latvian-based media Meduza is better in this regard). Not going into details, the official number of deaths in Moscow should be multiplied by three to get something close to reality, such a number in Russia proper should be multiplied by a factor somewhere between five and ten.

I guess that many of TWiV listeners are physicians, and they might be interested to know how Russian medics are battling with the pandemic. In brief, Russian health professionals wage a war on two fronts: not just with the disease, but also with their own superiors, because health administrators often treat them like dogs, e. g. denying them PPE, threatening to fire whistleblowers or even harassing the brave ones with police. These two articles about this are quite depressing to read:

Taken together with the cover-up of deaths, the ratio of medics who died from COVID-19 to the official death number is about 16 times higher in Russia than in other countries (like the US) as of mid-May. There’s a list of deceased health workers compiled by an independent group of doctors (in Russian:, and right now there are 359 names in it including 31 from St. Petersburg (the official numbers of total deaths are 5528 and 291 respectively). For more details on this issue, see

Sorry that the letter is already way too long (I could write another one criticizing the Russian analog of CDC if you would like, decided to skip that now), but I can’t refrain from briefly mentioning that despite yesterday saw the highest official number (6871) of new diagnoses in Russia proper ever (thanks to the regions not making their numbers up), in less than three weeks we are holding a national vote on a batch of 206 constitutional amendments including one allowing Putin to re-elect until 2036 (the reasons of the haste are unexplainable in few words) and already not too strict restrictions are being lifted.

Hence my pseudonym,

Yours sincerely, Worried about Russia.

Anne writes:

Hello Prof. Racaniello,

I heard you say in Sunday’s (May 31, 2020) TWiV that coronavirus cases are only shown in Moscow.  Here is a website that shows coronavirus case numbers by region.

FYI, this is a news site that reports on Russia from outside of Russia (to avoid censorship).

FYI, also from the Medusa website.


Sheela writes:

Dear TWiV Crew,

I have been a listener only for a few weeks, but an avid, obsessed one.  I have gotten through several of Dr Racaniello’s spring 2020 virology lectures and listen to TWiV, TWiM, and Immune whenever I can, which is unfortunately not a nearly enough as I’d like since I am a full time mom taking care of three kids and three dogs. Although I have no background in science, I have had a strange fascination with human immunity and pathogenic microbes since the 1996 Ebola outbreak.  One listener email said that listening to your pods had taken his knowledge to a higher level, but I think it’s far more appropriate to say that you have taken my knowledge to a much *lower* level.  I am intrigued with the low level microbial behavior (not anthropomorphizing – this is a word used even when talking about app and program functionality!) and the interface among virology, immunology, and epidemiology.  I have gotten so into this stuff that even my immunology PhD neighbor who is in drug development at GSK is sick of my questions.

A couple of questions have arisen in my mind from listening to your podcasts and I hope that you find the time to answer them.

1)  Through the pods and lectures, I have learned of the distinction between infectious and non-infectious viral particles (and appropriate assays). I have not been able to find anything on the particle:PFU ratio for SARS CoV 2.  I am assuming that it is quite high like most viruses and that most particles that a person sheds are non-infectious, especially since you are now seeing recovered patients being PCR positive for weeks after disappearance of symptoms.  If you inhale shed non-infectious particles, can your immune system treat that like inactivated virus and mount an immune response, or is there just not enough viral load from normal contact to achieve this?

2)  I have heard some of the Immune podcast facilitators and guests express skepticism about vaccine safety on an accelerated timeline.  I have also seen Alan Dove and Paul Duprex that tweeted articles about how Operation Warp Speed’s primary consideration in vaccine candidates is ease of manufacturing.  I am not an anti-vaxer; I am up to date on my shots as are my three kids and three dogs.  If I had been a mother with young kids when the Salk vaccine came out, I would have jumped on it.  However, I have apprehension about the safety and perhaps even efficacy of a vaccine brought to market on an accelerated timeline with tremendous political pressure on manufacturers.  I feel like going commercial will really be an extended Phase III and would rather wait and see what happens to others who are more trusting than I.  What are your thoughts?

3)  I live in Santa Clara county, CA (currently sunny and 20C with annoying winds) which, at the beginning of the US outbreak, appeared to be a hotspot.  It appears that our early lockdown was an effective mitigation measure.  Things are now opening up and most people wear masks in public (even, for some reason, alone in their own cars).  We are an environmentally conscious population and many people bring their own reusable bags to grocery stores; however, county ordinance now forbids this.  Isn’t it now known that the risk of transmission by fomites is very low, and doesn’t wearing your own clothes and bringing your own purse and children into the store present the same risk (or possibly more) as using your own grocery bags? I would like to clarify that we are not even permitted to bring our bags into the store.  This is not a question of making a store cashier touch them.  You will be sent back to your car to put personal grocery bags back, or asked not to pull packable ones out of your purse, or the grocery store will be fined.

Thank you so for the awesome work you do.  If I lived on the East Coast, I would volunteer to be an unpaid lab assistant and do your grunt work for you just because I find it so utterly fascinating.


Sandy writes:

Dear Twiv, 

I recently started listening over the last month and I am grateful for your podcast. I am a member of a chevra kaddish (Jewish ritual preparation for the deceased). This procedure is usually done within days of the death. There is a great deal of water utilized during this process. We do suit up in full body protective gear, masks, face shields and gloves. We have recently started doing zoom services with the funeral home doing the preparation of the body. I have the following questions:

1. Is there any data on how long the viral particles remain infective or present on the body, nasopharyngeal areas after death?

2. I know this is a loaded question. Is it safe?

thanks for all you do. 


Rupert writes:

Why do masks actually work?

Dear TWiV,

Greetings from yet another newish listener. Thank you for the clear explanations, and pointers to a whole world of viruses with weird names and fascinating histories.

I have a really basic question, which I suspect shows my primary-school level biology, but I’d love a clear explanation.

I know that when someone sneezes or coughs, droplets spray out in enormous numbers. Suppose someone with COVID-19 (or another similarly transmitted disease) sneezes near me. I assume that this means I’m going to be breathing in at least hundreds of particles with virus in them.

If I’m wearing an N95 mask, I guess that means around 5% of those particles will get into my system even so. That still sounds like quite a lot!

So how does the mask help me avoid getting sick?

I can think of a couple of ideas (maybe most virus particles get squashed by the immune system, so you need lots to get to good odds of getting ill? maybe the public health information videos about sneezing people were exaggerating?), but would love an answer from someone who actually knows how this works!

All the best from Cambridge (UK),


Karen writes:

Aloha, I have enjoyed the podcasts. I’ve been listening for the past few months. I have encouraged friends to listen as well, especially when they toot their horn without evidence. 

For the areas that have 0 or near 0 cases, I believe the people of those areas are eliminating Sars-CoV-2. 

Hawaii island has had zero cases for the past month. The protocol of testing-contract tracing-quarantine, along with masks and 6 ft social distancing, appears to have eliminated the virus from Hawaii, Maui and Kauai islands. Any new cases that occur in the future is because of people who travel to the mainland and return, or travel in from the mainland. This is the case for Oahu island. Hawaii state has third lowest number of cases among the USA states. 

If I understood correctly from the information discussed on your podcast, Sars-CoV-2 virus mutates, and it’s unknown if a vaccine would be the answer. I heard discussion regarding  revaccination periodically, and with the Sars-CoV-2 virus antibodies does not mean that person may not experience the symptoms again. Consequently, I see developing a vaccine is like shooting a moving target that replicates quickly.  I see the way to rid ourselves is by eliminating through the practice of a protocol such as test-contract trace-quarantine, and wearing masks when 6 feet social distancing isn’t possible, and social distancing especially when not wearing a mask. The problem is that to eliminate this virus requires everyone being on board. I realize islands and island counties have an easier time regulating and controlling incoming travelers.

If residents of the USA would be cooperative versus protesting practices that may lead to eliminating the virus, the USA would be in a better place. 

Please advise if my belief is off course, and why. I’ll listen to the podcast hoping to hear your response and discussion. If possible, when you do respond, let me know which podcast. 



Hawaii Island

Eric writes:

Listening to episode released on the 23rd a comment was made not to get political on a science podcast.

I found this comment ludicrous prima facie it also flies in the face of good science and expert opinion. 

For example to somehow ignore decades of social and economic injustice creating swaths of our society that have larger and more pronounced co-morbidities because it touches the no politics zone does a disservice to listeners. (luckily this comment specifically references a time you did not do that).

The ability for listeners to be open to information that flies in the face of their understanding of the world crafted by whatever reality bubble they inhabit should be the price of admission not the feedback in the complaints box.

Keep doing what you do, keep expressing yourselves in whatever method you deem necessary for that day. Myself, and others I assume realize you are humans living in a society and can make mistakes.  Your heart is in the right place.  Thanks for giving the release valve to anxious nerds like me who need to use knowledge to offset stress. 

Eric from Calgary Canada

Gary writes:

Hello to you all, and really enjoying TWIV. 

The insertion of 12 nucleotides into CoV2 introduces a Furin site which you have discussed before on TWIV.  The 4 aa insertion includes 2 adjacent Arginines which are both coded for by CGG . This has the lowest codon usage bias of the six found in CoV2, SARS and MERS.

Is this telling us something? 

Also doesn’t this argue against the “lab made” CoV2 “hypothesis”?  Wouldn’t a researcher more likely choose AGA as the codon to insert?

Just a thought.


Gorka writes:

Hello, I am a professor of Telecomunication Engineering in the Rey Juan Carlos University in Madrid, Spain and avid twiver (hopefully not in this sense A couple of chapters ago, you mentioned PPV and NPV and their interpretation. They are very important for public policy, because with a low prevalence of the disease, even good tests (and most of the ones which we can get in Spain and I suspect in other parts of the world aren’t) have a high degree of uncertainty. A positive in normal circumstances with a commercial test (5% prevalence of the disease, 95% specificity, 80% sensibility), can convey only a 50% of probability of being a true positive, which most people find completely counter-intuitive.

Even with better tests and a very low prevalence of the disease, this effect of compounded uncertainty appears.

People’s eyes glaze over when you talk about the mathematics involved, but in this case, they are very important and not so difficult to understand.

I have written a blog post (both in English and Spanish) with this example worked out and simple diagrams to try to make it more understandable (links at the end).

In any case, thanks for your down to earth explanations and your work making science available to your listeners.

Keep up the good work,


(my name is pronounced like pickled cucumber in Swedish or like hill in Russian, in case this helps).

Elizabeth writes:

Hi there,

Is there any truth to Blood type being associated with Covid and degree of illness? Holding out hope for any reason.

Thank you,


Austin TX

Erin writes:

Hello Immune Team!  I’ve been hearing about how blood type is being identified as a predictor of severity of covid-19.  Is this reliable information and if so could you talk about this further?

Thanks for all you do 🙂


Portland Oregon