Roshelle writes:

I listen to your videos and I could not find the answer for my clinical question: Is the patient with persistent positive Nasal swab RT-PCR by Quest considered contagious despite the fact that it has been 2 months since the first positive test, and no symptoms. 

Thank you for your time!


Roshelle Beckwith, MD

Noreen writes:

Enjoy listening to TWIV  in Ireland. There is something genuine, trustworthy and hardworking about you guys. You obviously love your work.

My questions are as follows:

Contraceptive pill, is it likely to increase clotting problems and risk of death and complications in covid?

Thalassemia and Thalassemia trait, are these likely to be the cause of increased risk for black, Indian, Italian and Asian people? These are the races most likely to have these conditions, as far as I know.

If yes, are there precautions to observe?

These questions may already have been asked???

Many thanks


Maurice writes:

Hi to my favorite twivvers & thanks for the mug.

My doctor son is a radiologist working in France (Maubeuge).

He recently forwarded me his catscan of a confirmed cov19 patient showing a faint “ground glass” shadow in the lung. He assures me this would not show up in a standard X-ray.

I say this because Alan Dove in twiv 594 mentioned that his wife with signs of pneumonia was sent home from hospital for self isolation because of a negative X-ray.


Shows the need for availability of quick covid19 tests as a better system of triage at Hospitals.

Hope my suspicions are unfounded and apologise if they are.


Troye writes:


I had a short question: I’ve been seeing reports of increased cases of Kawasaki Disease, is this possibly the caused by SARS-CoV-2? I had Kawasaki Disease as a child, are my kids 5 and 6 months at increased risk?

Thanks for the most educational and informative podcast available.


Anonymous writes:

Is the covid-19 loss of smell symptom acute enough to be used in a screening procedure that employs a universally detectable odor? 

David writes: 

Dear Kathy et al.,

Am I correct in learning from the podcast that once a vector that itself can induce an immune response is employed, its use a second time could be a problem?

I have heard the program a number of times. Listen to it on my daily 3 mile walks.

Be safe,


Jai writes:

Dear TWIVers,

Many thanks for your enlightening podcast. I learned of it from The Gist, where Mike Pesca gave you a great review. 

I’m sure you’ve seen this reported, and I’m wondering if you could comment on this study (The airborne lifetime of small speech droplets and their potential importance in SARS-CoV-2 transmission) reported on in The Washington Post.

Many thanks again for all the insights and knowledge you share. 


Jai (rhymes with eye)

P.S. excuse the weird formatting I’m emailing from my phone. 

Peter writes:

Hello Vincent: 

Toward the end of TWiV613 you looked for a famous quote addressing what we know, think we know, and don’t know.

Rich found his Socrates quote, but the first that occurred to me is from Bertrand Russell, which is along similar lines. I’ve had to look it up to quote accurately:

“The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts”


Maureen writes:

The meat packing plant outbreak you discussed this week took place in South Dakota- not North Dakota. Not all flyover states are the same. Writing from Montana where we have a Democratic gov who has some common sense. Stay well. 

Vinny writes:

No your eyes are not deceiving you. Doctor Racaniello and I have the exact same names.

He may remember me as I wrote to him the past.

Needless to say, I am an avid listener these days.

I heard the expert panel state that all viruses mutate and that SARS COV-2 like all viruses has mutated but not into something more virulent.

I’ve also heard the panel comment on how everyone and their mother is writing papers to get “noticed” .

Can you comment on this study as reported  by NBC news?

Thank You

Vincent Racaniello (seriously!) 

Thalia writes:

Hi TWIV gang!

I’m a PhD student in Anthropology at Princeton and have been very much enjoying your show.

I have a question: I sometimes hear doctors and experts saying that they’ve never seen a virus behave the way Covid-19 behaves. They’ll mention the fact that the virus can linger in your system for weeks after you recover, causing relapses after weeks of feeling fine. Or, the fact that it seems to not affect children very much. Or the fact that it seems to affect so many organs of the body, and result in quite a variety of symptoms.

My question is: how different is Covid-19/Sars-Cov-2 from other viruses? What viruses should we be comparing it to? When we first became aware of HIV, no one thought that it resulted in a longterm condition. Should we be asking if Covid-19 could result in a longer-term condition, too? I guess the most obvious comparison is to SARS-1, which makes a lot of sense. But that’s the only comparison I’ve heard people make…Maybe we should be talking more about what viruses Covid-19 is comparable to, because that will shape the questions we ask…

All the best from Princeton, where the squirrels now outnumber the students…


Mike writes:

Dear Prof. Racaniello:

I have become a listener of your TWIV podcast in recent months for…reasons.  In fact, a long time ago in a galaxy far, far away I did a brief stint as a molecular virologist in Alan Campbell’s lab at Stanford, but obviously not on coronaviruses.  It’s been two decades, and now I’m a pediatrician, but for probably more than half of any given day at work, I am working with viral diseases, so that prior experience is relevant to my career.

Anyway, I was listening to your episode 613 and one of your crew expressed some skepticism that Jenner’s cow hide was still preserved.  In fact, it is and I have seen it with my own two eyes when I was a 4th year medical student doing an international Infectious Diseases rotation At St. George’s Hospital in south London back in 2005.

There is a framed cow hide (it was in a stairwell, of all places) with a plaque next to it that explains that this is *THE* cow hide that Jenner used.  Now, obviously, I can’t prove that it is the genuine article, but there is a cow hide with multiple pox-like lesions that appears to have been tanned and preserved in that stairwell in that hospital and they are all very proud of it.

So there you are.

-Mike Ginsberg, M.D., M.S., FAAP

David writes:


Re: TWIV611 and “wet finger” dentistry: when I was a teenager C.1980 my orthodontist not only didn’t use gloves, but didn’t use soap or any disinfectant when he washed his hands. I commented on this unhygienic practice once and he said, “no, I just rinse with water.” I was amazed and disgusted. It’s no wonder I got sick as often as I did back then.


Rodrigo writes:

Dear Vincent and Crew,

Thank you so much for all you do. I listen to and learn from every minute of your podcast. You guys are truly terrific!

On the topic of Far UV-C light, it seems like you may have it backwards with regards to its safety. This peer-reviewed paper published in Nature 

Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases


[…] due to its strong absorbance in biological materials, far-UVC light does not have sufficient range to penetrate through even the outer layer (stratum corneum) on the surface of human skin, nor the outer tear layer on the outer surface of the eye, neither of which contain living cells; however, because bacteria and viruses are typically of micron or smaller dimensions, far-UVC light can still efficiently traverse and inactivate them[..]

[…] However as discussed above, based on biophysical considerations and in contrast to the known human health safety issues associated with conventional germicidal 254-nm broad-spectrum UVC light, far-UVC light does not appear to be cytotoxic to exposed human cells and tissues in vitro or in vivo […]

Please discuss this paper in your podcast. 

Thanks again and Best Regards,


Félix writes:

Hi Twivvers! 

It’s Félix again, from Chile.

Unlike last time I sent you an email (which was I think 6 weeks ago?), now I know your names! 🙂

First off, thank you so much for addressing my questions about immunity and vaccines. Episode 597 with Jon was pretty hard to follow, but incredibly worthwhile to do so. I learned so much from that interview alone. I’m also now listening to Immune, and loving the work you are doing there with Steph, Cindy and Brianne, Vincent.


Okay now regarding online chorus. This is for Kathy and Rich

Given the pandemic-derived isolation we’re living in, I’ve been testing a lot of platforms to interact with my friends at a distance. Zoom, which you guys mentioned, works very well, but it’s still not the best in audio quality nor sustained audio timing. After doing a lot of research and testing various video alternatives to Zoom like Jitsi and audio-only platforms like Discord, we’ve settled on Mumble. If you can work with just audio and forfeit video, Mumble is definitely the best solution. Here’s why I think that:

1. Free Software: it’s out in the open. You can trust it.

2. Very, very efficient. Incredibly efficient. We’ve tested it thoroughly, and have found that the latency is really low, the resource demand is low, and that the timing of the audio keeps being pretty consistent.

3. Noise reduction. The Mumble client comes with really good noise reduction settings. My headset is old, and my computer introduces noise in the mic, yet Mumble is capable of filtering all of that out… in real time. What a ridiculous program. I love it. When I speak, my friends don’t hear any of my headset’s noise 😀

Anywho. Those are the advantages. The main disadvantage is that since the project is not a service, you need to find a host.

The wiki keeps a list of the United States hosts:

Some are free, some are paid.


You can also host it yourself, if you want. We’ve done so here with some of my friends, but bear in mind that we’re all more or less computer engineers and don’t mind having to mess around with settings

I’d recommend first trying it out with a host, and then hosting your own if you find that you like it and that you want to have full-control over everything 🙂

Go to to check out the project, and feel free to send me questions about it if you want to know more. We’ve been using it daily for about 4 weeks.

Love what you do, guys. Staying informed helps me to keep my anxiety in check.

What you do here is, in a way, you guys caring for everyone else.

Hugs and stay safe 


Siobhan writes:

Hi TWiV team,

Thanks for everything that you do! I first stumbled upon your podcast last year while preparing for Journal Club – Episode 348 Chicken Shift weighed heavily into my interpretation of some papers about Marek’s Disease Virus and the evolution of pathogenicity as a result of “leaky vaccines”. Some new research about MDV vaccination and virulence was published in March ( I’m interested to hear your thoughts on this once the pandemic blows over!

I’ve been singing in choirs since I was in elementary school. Now I’m halfway through a Master’s in Virology and still sing in a choir every week. It’s been one of the biggest things keeping me going when my MDV BAC clones don’t turn out right. There’s always some great music and some even better people who can brighten my day. I didn’t realize Rich and Kathy are also singers! I don’t know about you, but the simultaneous cessation of research activities and choir rehearsals has been devastating. I was set to present at my first conference (International Symposium on Marek’s Disease and Avian Herpesviruses) in June, and attend a choral conference in May. Both have been cancelled/postponed. 

Anyway, it was great to hear you mention Phoenix Chamber Choir’s “For the Longest Time” in today’s episode – many of my friends are in that choir! They’re tickled that a) I listen to 2h virology podcasts for fun b) the people who make the podcasts watched their video. I’ve convinced them to give TWIV a listen since you watched their video. 



Torcuato writes:

Dear Twivers,

The Spanish Government has just announced the initial, preliminary results of its ENECOVID 19 serologic survey for SARS-cov-2. It is based on random, representative sample of over 60000 people selected by the Instituto Nacional de Estadística (akin to the US Census Bureau).  Rigorous stuff.

Everyone had a “quick” antibody test and most also consented to blood draws for an Elisa test (only a quarter of the samples have been analyzed so far though, so the Elisa results do not feature in the preliminary analysis). These will be repeated two more times, in 3 and 6 weeks’ time.

Formal publication is expected soon, but here are some highlights (alas, sans confidence intervals):

-Overall IgG prevalence of 5% nationally.

-Significant variation across provinces (from 1.6% to 14.2%).

-Among people who reported experiencing anosmia at some point in the previous two months, IgG prevalence is 42% (!).

The infection mortality rate was not specified, but here is my back-of-the-envelope calculation:

-Given that the population is 47 million, about 2,35 million are estimated IgG positive.

-PCR-confirmed deaths stand at 27100 (as of 5/13), but there is unaccounted for excess mortality (6000 as of 4/28), so actual number could be as high as 33000.

-If we are not too fuzzy, this gives a rate between 1,15% and 1,4%.

As a note, they mentioned in the press conference that in those individuals with Elisa already performed, the two kind of tests agreed 97% of the time, if I recall correctly (given the low prevalence, presumably they agree on a lot of true negatives). 

Official press note in Spanish:

English news article:



Brian writes:

Article referenced concerning 80,000 deaths (Stat) is from 9/2018. It 

was not about the 2019/2020 season. Woopsie!

Philip writes:

Dear TWiV,

It’s 82 degrees Fahrenheit here in Atlanta and partly cloudy. I’ve been listening (admittedly off and on) since around 2014, and I remain enamored of “Threading the NEIDL.” I work in a grocery store, and I have a question that will probably make me seem like an idiot. I’ve often wondered in the past couple months whether there’s real value in elbow bumps (a practice I avoid), or, more generally, using an elbow to open a door or perform other typically manual tasks to the extent it’s possible when I can’t immediately wash my hands. I’m specifically wondering whether, after initial physical contact with the surface of the elbow, a virus will travel around on the skin, but it’s just not likely it will make it all the way to a person’s hands or face? Essentially, once on a surface, how does a virus spread across that surface? Thank you! 

Please continue to be grumpy,


Mark writes:

Hey Guys: 

Was looking at the innertubes this pm and saw this popsci article on how vaccine disinformation spreads through social media.  It discusses the work of an old collaborator of mine, Neil Johnson.  The paper  behind the Nature paywall, always a pesky problem when you no longer work in academia.  But a new draft paper is now up on arXiv.  This is the kind of work that gets Neil in trouble. 



Larry writes:

TWIV heroes-

Thanks for all you do. I consider it my civic duty to try to listen to all of TWIV to stay informed and above the misinformation in this pandemic. We (including uninformed lawyers like me) are so lucky that you folks continue giving your time to do this.

In a recent episode, Dr Griffin mentioned that–because viral load decreases–many patients are PCR negative at the height of their illness toward the end of the second week, in the middle of the famed cytokine storm.

On the other hand, with regard to the Korean reinfection study also mentioned recently, you noted that the supposedly reinfected had likely not been reinfected but instead had high enough remaining virus RNA well post-illness to trigger a positive result.

How do you square these two? Is it that the Korean threshold cycle number was significantly higher?

Thanks so much for all you do


PS I ask in part because my mother (who is conventionally considered high-risk because she is on anti-rejection drugs for her 2013 vintage kidney transplant) is currently SARS-COV-2 PCR positive. She’s totally asymptomatic and just fine but had significant COVID-like symptoms in February. Those symptoms hospitalized her in February but resolved before they could identify any cause. The current theory among her docs is that she may have had COVID19 in February, but enough vestigial RNA remains such that she is PCR positive on her first test three months later. Seems odd if Dr Griffin’s patients were already PCR negative much, much, much earlier, though I guess (IANAV) could be explained by her immonosupressants.

Chirag writes:  (can you make a challenge trial safer using an attenuated virus for the challenge?)

Thank you for your great podcast! With episode 613 about cowpox which can protect against smallpox, there may be a way of making challenge trials safer. Looking into the different vaccines being developed for the SARS-CoV-2 coronavirus, there is only one group working on attenuating the virus itself. From what I have read, attenuating a virus can take a long time, so this might not even be relevant. If, however, we don’t have a vaccine yet and the group successfully attenuated the virus and it passed phase I, could that attenuated virus be used to test itself and other vaccines?

Again, I am not in any field related to viruses or immunology or even biology, so there may be something blatantly wrong. And, since attenuating a virus takes so long, we might have already approved a vaccine hopefully without challenge trials with a wild dangerous virus using other methods of vaccines.

Thank you,


Nate writes:

Dear TWIV—

Regardless of what choice the US FDA and others in this country make on the ethics of vaccine challenge trials on volunteers, are other countries making the same call? What happens if a vaccine is developed elsewhere using volunteers or, worse, coerced or uninformed participants (say, Uighur prisoners for example).  Is that a possibility? Would or should we refuse to use the vaccine if that happens?

Would love to hear you discuss.



Mark writes:

Dear all: 

First, I’d like to acknowledge the greater TWiViverse’s membership in the exulted firmament of the professoriate before I begin referring to you in the vernacular. 

You frequently refer to various statistical models used for epidemiology, surveillance, and prediction.  Rich, in particular, seems somewhat enamored of the IHME models.  The statistics and biostatistics folks at UW are significantly less sanguine.  I do a lot of statistical modeling and ML work and this kind of modeling is not my bailiwick as I am a humble soft condensed matter physicist but I can tell you that these econometric models are essentially a bunch of crap. You really don’t want Economists making your pandemic forecasting models. I mean curve fitting of the second derivative of time on a log scale? Sheesh! And that Stanford prevalence study!  Don’t get me started on that.

So, Vincent, I’d like to suggest you invite the Director of the Center for Applied Statistics at Columbia and Columbia professor, Andrew Gelman to the program.  He and his group have provided excellent critiques (in his blog) of many of the models being released as preprints:

Finally an appropriate quote about the IHME model: “I had always imagined that if we fell to pieces, it would be because we did something clever but deeply unwise. It is very depressing to realize that we may well end ourselves through sheer incompetence.” 

Love TWiV and really enjoyed Vincent’s Virology course especially the pop quiz polls which demonstrate that while I may be 3X older than the typical Columbia College undergrad I remain 3% smarter. 



Worried about Sweden writes:  

Dear TWiV,

I was very disappointed to hear you all uncritically accept the letters you received praising the Swedish approach. Although it is true that the majority of the Swedish public (64% in the most recent poll I can find) do approve, many in Sweden have been very horrified by how this has been handled, and many more in its Nordic neighbors are looking on with dismay as well. One of the most famous of criticisms of Sweden’s strategy is this letter from 22 various researchers, scientists and academics who are very critical of Sweden’s strategy.

As of yesterday, May 13, a total of 3,460 Swedish people have died as a result of COVID-19. This means that Sweden (population 10,3 million) has now declared over 2400 deaths more from COVID-19 than all its three neighbors combined (Denmark, Norway and Finland, total population 16,7 million), with only about 3000 more cases (and the lowest testing rate of the Nordic countries). As of today, it has fifteen times the amount of dead that Norway does (Norway has 229 confirmed as of yesterday). Its deaths per millon is among the highest in the world , even higher than the US, higher now than Italy, and much higher than any of its neighbors. Sweden’s excess mortality is up by 29% overall, and by 87% in Stockholm.

On April 28th it was reported that some ICUs were at 0% spare capacity. There were reports that patients from full ICUs had to be transported to those with spare capacity. The authorities refused to state which hospitals had exceeded capacity. However, the authorities have for weeks acknowledged, and continue to acknowledge, that the hospital system is severely stressed. Sweden has had to import resupplies of a drug used in the ICU from Norway due to shortages caused by high demand.

Most disturbingly, several whistleblowers at health care institution have come forward to say that triage protocols were being inappropriately applied to elderly and disabled individuals who have been denied ICU care and instead given palliative care aka left to die. An official investigation has been launched [1], [2], [3], [4]. There are many reports like this one of elderly patients unable to even be tested, and dying uncounted.  There are also many  reports like this one of disabled and/or elderly people being denied care while in hospital, despite there being vacant places in the ICU. The patient in that last article was not only refused ICU care, but wasn’t even given morphine to ease the pain of her passing. During the time many of these accusations were made, Sweden’s Karolinska Hospital had an ICU survival rate of 80%, far above the international average, which gives support to the accusations that elderly and infirm were denied treatment.

It is well known that many of Sweden’s deaths have occurred in elder care homes. It has also been acknowledged by all of those in power that this has been an abject failure of their proposed stratify and shield strategy (which would allow the virus to run through younger population while protecting the elderly population). However, it has become increasingly common for those in charge to not fully take the blame, but rather to blame the situation in elder care homes on recent immigrants: “some failures of the Swedish model have been acknowledged. But they are often linked to the lack of “compliance” of immigrants. Former chief epidemiologist Johan Giesecke explains the failure to protect the elderly in nursing homes with reference to “asylum seekers” and “refugees” on the staff, who “may not always be understanding the information””.

Although the authorities will outright deny that their strategy is herd immunity when confronted directly, they routinely mention that herd immunity can be achieved soon in Stockholm, and have been saying that it might come in May and now that it could happen in June. Tegnell, the head epidemiologist around whom a sort of cult of personality has formed, said in an interview that herd immunity can be relevant in Sweden and praised the British idea of herd immunity (before they switched to containment) as “Where we need to go”. When asked the question “WHO demands more action and believes that it is a fire that you should not let burn?” Tegnell replied “It is as with forest fires and others, that if you can just get it to burn a little and slowly then you can get it to burn out.” Suggesting they are enacting a “controlled burn” herd immunity approach.Watch what they do, not what they say and what they are doing is implementing a very risky natural herd immunity strategy. Clearly “burning” a few elderly and disabled people is a price he and the others in charge are willing to pay to achieve the ‘end result’ (as they often are careful to call it) of herd immunity. Well known British epidemiologist Neil Ferguson said regarding Sweden’s strategy: “I mean he’s [Johan Giesecke, Tegnell’s mentor and advisor] basically saying just allow all these older people to die because he doesn’t believe we can maintain measures in place”.

Children who have parents with vulnerabilities are forced to go to school even though this puts their parents at risk. If they choose to keep their children at home, they risk fines and possibly having their children removed from them by the social authorities. This video by Dr. Marcus Carlsson, a Swedish academic who is one of the 22 researchers involved in resisting the government’s policies shows this heartbreaking dilemma from the perspective of parents put in this impossible situation by the Swedish government.

With only the bare minimum in regulatory mechanisms, Swedish social distancing adherence is starting to waver. Although Sweden’s mobility does show a decrease, when compared to its neighbors, mobility was not down as far as Denmark, Sweden or Finland at any point.

Even in light of its lack of formal lockdown / very soft NPIs, Sweden’s economy is set do to as badly and perhaps worse than its neighbors  [1], [2], [3], [4].

The justification for all of this is boils down to the thought that ‘nearly everyone in the world will get it in the end anyway, so we may as well get it over with quickly, let it burn through the population in a controlled fashion while reaching natural herd immunity, waiting won’t change anything’. This is a very cynical view. One only has to listen to your own Dr. Daniel Griffin’s reports over the last few weeks to know how much progress has been made in terms of clinical treatment, and a vaccine or more probably a drug treatment could occur that would save many more lives. 

Treatment aside, Test, Trace, Isolate has been shown to work in several countries now and that does not require either treatment innovations or ongoing, strict lockdowns. There is absolutely no reason that ‘most everyone’ needs to get this disease.  Another problem is that we don’t know the true mortality rate, we don’t know the long term effects with any certainty, we’ve already seen a new Kawasaki-like syndrome develop in children, we don’t know how durable / meaningful immunity is, we don’t know if it can cause antibody dependent enhancement, etc. Mike Ryan at the WHO was recently very critical of a herd immunity approach to this disease for some of these reasons and he said: “Humans are not herds, and, as such, the concept of herd immunity is generally reserved for calculating how many people will need to be vaccinated and the population in order to generate that effect…. So I do think this idea that ‘maybe countries who had lax measures and haven’t done anything will all of a sudden magically reach some herd immunity, and so what if we lose a few old people along the way?’ This is a really dangerous, dangerous calculation”. Many believed he was making this comment specifically in regards to Sweden’s strategy [1], [2].

Meanwhile in neighboring Denmark, the caseload has become low enough to reopen society to a very large degree while implementing the Test, Trace, Isolate [TTI] strategy that has already seen proven success in countries like South Korea, Taiwan, Hong Kong, Singapore, New Zealand, Iceland, the Faroe Islands, etc. Denmark and Norway are in talks with other seven other countries that have gotten their caseloads down very far to form a travel coalition. One article on this proposed collation specifically includes the line “Sweden is not invited”. Finland is also concerned about infection spilling from Sweden across its borders, as the border region with Sweden has the highest infection rate outside of the capital. It is easy to see how in a world where countries can successfully implement TTI polices, Sweden could find itself increasingly isolated as it is very possible (and already informally discussed in Denmark and Finland) that tighter border controls with Sweden could be enacted. Unfortunately, Tegnell has come out and admitted that TTI is not possible for Sweden due to how widespread its outbreak is. A new article came out just today in DR showing that the overwhelming majority of Danish parlimentary parties are against reopening the border to Sweden. The accompanying graphic is quite telling. 

So please do not take the cheerleaders at face value. One Swedish expert, Stefan Hanson, an infectious disease doctor and a PhD in international health, says: “We have come together in what can almost be likened to a mass psychosis. We have our claws out. We don’t want to hear any criticism”.

I am writing to you anonymously because in Sweden there is a principle called “Jantelagen” which means that anyone who goes against the grain is liable to be punished / bullied for defying the “Law of Jante” which can be defined as conforming to the majority opinion and defering to authority, almost with an unthinking deference. Most of those who have spoken out publicly have been viciously attacked, sometimes with quite vile abuse. At least a couple of critics have received so much abuse they have shut down social media accounts as a result. It is suggested by some that there may actually be Swedish troll farms that are involved in this type of abuse, but I think it is likely that this is just the Swedish hive mind exhibiting mass psychosis with the claws out, as Dr. Hanson suggests.

It would be wonderful if TWiV were to interview one (or more!) of the 22 researchers. I am not sure who might be best, but if you all go through the list and find someone who fits TWiV it would be great to hear them speak. In my view, Sweden’s COVID response is akin the US’ climate response: far outside of the scientific mainstream, dangerous, and unethical. I truly hope that Sweden will change course soon, as I think there is still time to do what the other Nordic countries have done, to get the caseload far down and implement TTI, but although that is in theory possible it seems sadly unlikely due to the social dynamics at play.

Sincerely, ­

Worried About Sweden (WAS)

JR writes:

Dear TWiVers,

Greetings from New York City and a heartfelt thank you for all you do–I truly enjoy your podcast and have been recommending it to everyone I know (and, you’ll be happy to note, they’ve expressed much gratitude for the recommendation).

I have dozens of friends who live in Sweden and I visit just about every year (unless there is a pandemic!). In speaking with several of my close friends in Sweden and in thinking about TWiV 611, I’ve come to realize the depth of the chasm between their current mentality and that of the rest of Earth. I’m curious to get your thoughts/feedback on my three latest working theories regarding the “success” of Sweden (though I realize this analysis may benefit from an epidemiologist’s input, as well). And please note I certainly don’t intend to offend or even slightly offend any Swedes!

1. It’s no success at all.

True, culturally they are more socially distanced than Italy. And culturally they appear to be strict rule followers. A significant portion (over 90% in some industries) are working from home. There was a 90% drop in travel over Easter.

The criticism, however, is not that they are doing nothing. It’s that they aren’t doing enough, and are letting “the epidemic run its course.” The implication is that they’re voluntarily doing 90% of what their Scandinavian neighbors are doing. But their death rate? It’s not even in the same ballpark as those same neighbors: currently (May 13, 2020) it’s 343 deaths/1 million population, which is 816% Norway’s, 672% Finland’s, and 372% Denmark’s rates (see, the same source used by the Oxford COVID-19 Evidence Service to calculate their case fatality rate figures). By the time you read this, I’m sure the gap will have expanded even further.

This only highlights the number of lives that can be saved by enforcing strict social distancing measures and closing down schools, restaurants, bars, etc. (i.e., “shutting down the economy”). Because Sweden is not doing these things, its population is suffering a death rate that is orders of magnitude higher than that of its neighbors. And the evidence indicates that they can lower their death rate by emulating their neighbors and much of the world.

Indeed, Sweden’s own Dr. Anders Tegnell (head of the country’s response to Coronavirus) has publicly stated that “the death toll really came as a surprise to us” and is “really something we worry a lot about.”

2. Effectively, they are free-riding on everyone else’s more severe responses.

Due to the global “lockdown,” there is very little travel into Sweden these days, so there is a significantly lower number of infections coming from outside Sweden. So even though large swathes of Sweden’s economy remain open for business, more rampant spread is kept at bay because so many other countries are locked down.

This is reminiscent of those who choose not to have their children obtain a vaccine, yet those children remain protected from disease due to herd immunity. Or those who do not change their behavior but benefit from better overall air quality because many others make a concerted effort to reduce carbon emissions. Historically, Sweden has acted as a “model citizen” country, but its current approach to SARS-CoV-2 diverges from its customary practice.

Infection rates and death rates gathered thus far strongly suggest that lockdowns have successfully flattened the curve in the local communities and countries which have adopted such strict measures. Isn’t it possible (maybe even likely) that lockdowns not only help each population group subject to such measures, but also help combat spread throughout the globe, and therefore affect all of us?

3. If you put #1 and #2 together, Sweden is a dangerously unworkable model for other communities to adopt. If today’s social distancing and travel restrictions around the planet are abandoned in favor of Sweden’s more relaxed approach, spread of disease will increase exponentially. Paradoxically, if the world goes the Swedish way, neither Sweden nor any other country would be able to benefit from the free-rider effect and Sweden itself might experience a dramatic increase in its own caseload and mortality rates (or, as John Donne put it, “no man is an island, entire of itself”). Considering that Sweden’s current death rate is already disproportionately high compared to its more restricted neighbors, that portends a grisly result for all humankind.

All this suggests that the approach all countries (including Sweden) ought to follow is what TWiV has been advocating all along, and which has been relentlessly pursued by countries like South Korea, Taiwan, New Zealand, and others: test and trace, test and trace, test and trace!

Again, thank you for everything that you do!

-JR (I would like to remain anonymous, but my initials are innocuous enough)

Joe writes:

Hi TWiV!

Hope you are all well! I just wanted to ask a quick question regarding tennis and SARS-CoV-2.

Here in the UK, the government have allowed singles tennis to be played between people who do not live in the same household. I wanted to ask if you had any thoughts about how the virus may or may not survive on the surface of a tennis ball. Would the force the ball is being hit at, and/or the high RPM of the ball have an impact of the survivability of the virus on the ball’s surface?

Best WIshes,


Cathleen writes:

We see a tremendous amount of information about face masks, but nothing about eye protection. If I wore, say, my onion cutting glasses, would I have increased protection.

I would be quite a fashion statement.

Thank you for providing sane information. 


Chris writes:

Hello Everyone,

London, Ontario, Canada. 1C and sunny. Snowed overnight. Will winter outlast covid? Sure feels like it. 

So if roughly 80% of cases are mild, why not do a controlled herd immunity strategy? Tell the high risk folks to stay put, but allow the young and healthy to volunteer for a 14-day virus program. Infect, sequester, recover, test for antibodies, clear for ending quarantine. Rinse and repeat. 

Since we know the approx number of people even in the low-risk group will have a serious reaction, give anyone in the program monitoring by the covid centres, staff and supply ventilators accordingly. Acute patients get extra help. Most people have mild cases and recover. Cycle this through a few cities at a time so resources can be pooled. Once there’s enough herd immunity in a given area move the circus to the next town. 

Seems like sequestering people for 14 days and knowing they’ll get sick, recover, and probably be fine after and having the resources on hand in case they’re not is a whole lot better than an indefinite suspension of normalcy for something we’re all going to get anyway. 

That’s my 5 cents since we don’t have pennies in Canada anymore. 

Keep on TWIVing in the free world!


Erin writes:


Im a mom in Texas, two weeks ago I discovered you and began listening to all the episodes of your show from January through present.  I have made it to April.  Im so thankful for the calm, quality information. 

Can you please talk about how we can get to herd immunity if we are all sheltering in place?  I can’t rectify these seemingly divergent concepts.  

Why doesn’t each extended shelter in place order mean boxing ourselves in to have to wait the requisite years for a vaccine? 

Thank you! 




Sent with love. . 


“It takes two to make a thing go right …. ”

Ken writes:

Why do so many American people elect such incompetent morons to their government?  It seems to me that the USA constantly claims ‘exceptionalism’, (it wages endless losing wars to support that stupidity,)  while in fact it’s no better than a banana republic, run by morons and criminals whom it seems are immune from any consequences.

  I know this isn’t a virology question but the incompetence and barbarism of American society, of its culture,  has to be faced eventually.

  You cannot go on like this or you are finished.


Annie writes:

What will destroy the S proteins on this virus rendering it ineffective?before entering the body, like on surfaces?

Can this substance be put into a fogger that could be used in stores and homes?

I won’t take a vaccine!

I will not accept the ingredients used to make vaccines!  

Can we focus on ways to stop the virus in other ways?

Michael writes:

  1. Thank you!  One of my daughters recommended your podcast on antivirals and risks in the dentist’s office.  It was understandable, interesting, and enlightening.  It makes perfect sense that a drug like remdesivir, which interferes with viral RNA replication, would be most effective if given during the initial, rapid-replication phase of SARS-CoV-2 infection.  And I now have a healthy (?) appreciation of the ability of dental “power tools” to atomize saliva.
  1. Question:  Among the many enigmas of COVID-19 is its variable severity.  Many cases are asymptomatic; but sometimes it devastates the lungs, circulatory system, kidneys, brain, etc.  Could an infection by one of the four common-cold coronaviruses confer a degree of immunity (perhaps temporary) to SARS-CoV-2?  Might such infections also explain some of the false-positives we now see in serological antibody tests?  Is this possibility under investigation, and if not should it be?

Thank you very much for your attention.


Francois writes:

Dear Vincent,

Long time Twiv (and Twim) listener here, and recent subscriber to Immune (can you believe I did not know it existed?). First of all, let me commend you and your team for being the epitome of intelligent vulgarisation of science – as a physician, it has helped me remain both entertained and aware of developments in basic science, for which I thank you.

I am writing to you from grey skied Wisconsin, where the temperature is currently 280.15º K. I recently accessed some of your episodes on YouTube and noted comments complaining about weather discussions – I strongly disagree with their authors, as did the narrator’s father in Proust’s In Search of Lost Time, whom I quote at the end of this correspondence.

I am writing to you with one suggestion and one question:

– Question: I don’t believe that you have discussed (yet) this article on any of your podcasts: Wölfel, R., Corman, V., Guggemos, W., Seilmaier, M., Zange, S., Müller, M., Niemeyer, D., Jones, T., Vollmar, P., Rothe, C., Hoelscher, M., Bleicker, T., Brünink, S., Schneider, J., Ehmann, R., Zwirglmaier, K., Drosten, C., Wendtner, C. (2020). Virological assessment of hospitalized patients with COVID-2019 Nature

I am curious to hear your/your guests’ take on it, as well as your assessment of the clinical significance of their findings regarding seroconversion and prolonged shedding. My reading is that transmission occurs most likely early in the course, at a pre- or minimally symptomatic time, but that there is also potential for continued infectious shedding of virus (which I infer they also seem to suggest is unlikely to happen from fecal-oral route) late in recovery.

– Suggestion: an episode of yours that I fabulously enjoyed featured both a tip-top title (“No Reston for the Weary”) and a guest vying for the title of Most Interesting Man in the World, in my opinion, Jens Kuhn. A podcast I recently started listening to, Conversations with Dr. Bauchner, from the JAMA Network, featured another strong competitor for the title, Nicholas Christakis. The work that both of your podcasts have produced on the current pandemic has been superb, and I believe in sharp contrast (unfortunately) with the ambient low quality of the discussion. A crossover or collaboration would be incredible.

François Blumenfeld-Kouchner

In Search of Lost Time / Swann’s Way [C. K. Scott Moncrieff translation]

But Bloch had displeased my family for other reasons. He had begun by annoying my father, who, seeing him come in with wet clothes, had asked him with keen interest:

“Why, M. Bloch, is there a change in the weather; has it been raining? I can’t understand it; the barometer has been ‘set fair.'”

Which drew from Bloch nothing more instructive than “Sir, I am absolutely incapable of telling you whether it has rained. I live so resolutely apart from physical contingencies that my senses no longer trouble to inform me of them.”

“My poor boy,” said my father after Bloch had gone, “your friend is out of his mind. Why, he couldn’t even tell me what the weather was like. As if there could be anything more interesting! He is an imbecile.”

Beth writes:

I am a very new listener to your highly informative podcast.Somehow learning about how viruses work is calming to me.

I found the interview with Richard Hatchett of CEPI eerie, encouraging, and heartbreaking. Eerie because of the timing, so soon before the COVID19 outbreak started in Wuhan; encouraging because of the news about global cooperation to fight emerging diseases and innovate solutions to get vaccines to the public faster; and heartbreaking because the United States seems to be absenting itself from international efforts to address the pandemic.

I have a college student who may have contracted COVID19 in late February. Her symptoms were very much like the ones described in an email read on a recent podcast (104° temperature, coughing and fatigue) for about a week. I hope she can get an antibody test, but I’m wondering how long after possible infection do antibodies remain in the system?

The matter of if her college campus opens in the fall has an extra twist. She renewed the lease on her off-campus apartment and lined up a roommate for next year. There’s no reason for her to stay there if instruction goes totally online. What if the school stays closed in the fall and opens in January, or vice versa? More uncertainty on top of too much uncertainty already. And, of course, she hates online instruction.



Christina writes:

Hi TWIVers, 

This is Christina, a long time listener and fan 🙂

I’m writing to you with regard to the dose-dependence in disease outcomes.

Our lab actually does infectious dose studies of avian influenza in chickens and ducks. We do this to determine if an avian influenza virus is more adapted to one species or the other. In our experience, dose and route of exposure can affect infection or disease outcomes. I’d like to share some of our findings in a shameless plug on a paper we published last year 🙂 

When we directly inoculate birds with a particular virus, we only observe  infection at the medium and highest doses. We get more or less the same outcome in both groups, i.e. ~90% mortality and lots of viral shedding through oral and cloacal routes. On the other hand, the survival rate on the contacts of these groups was dose-dependent. We know that the contacts were all infected because they become seropositive and they shed virus, although at lower levels. Our group is not the only one that have shown this phenomenon; we see this trend over and over again. 

We don’t really know how much virus those contact birds get. But my impression is that they get exposed to a ton of virus. My guess is that key difference is in exposure since contacts get smaller doses multiple times instead of a bolus shot of virus up the choanal cleft (roof of the mouth). Maybe the immune system has more time to deal with the virus, who knows?

So yeah, I do think that route and dose can determine disease outcomes. It would be interesting to see if that is the case for SARS-CoV-2. 

Here’s the link to our paper: 

Pathogenicity and genomic changes of a 2016 European H5N8 highly pathogenic avian influenza virus (clade in experimentally infected mallards and chickens

Thank you so much for your service!! You are doing such an awesome job!I feel so much more confident when people ask me about the current outbreak because I have a source of solid information: TWIV. 

It is currently 12 degrees Celsius in Athens, Georgia.