Anne writes:

Hello a Prof. Racaniello and team,

A link with comprehensive info about COVID-19, if you haven’t already posted it.



Volker writes:

Dear TWIV and TWiEVO experts,

here are my current questions not yet answered by your incredible useful service to the public:

Pretty early in the year it was mentioned on TWIV that retrospective analysis had identified a Covid case in early December that was not connected to the fish market. Since then I did not hear about this anymore. But the fish market was at least on TWiEVO mentioned as the source again. Do you have any updates in this regard? Is the fish market probably the source or not?

How do you interpret the evolution in China? Is there already an effect of herd immunity visible due to earlier spread of the virus?

Could you please cover the effects of (potentially) overwhelmed health systems deeper? More reports from experts at the front? I heard that even in Switzerland they are afraid of running out of lung ventilators.

Situation in Munich: It is far too warm for mid of March. Schools will be closed from next Monday, the companies are training or already implementing emergency plans. In the shops you miss three things: disinfectants, noodles, toilet paper 😉

Thanks a lot and best regards,


Josh writes:

Dear TWiV Doctors,

I have been enjoying your recent coverage of the Coronavirus and wanted to ask a question:

Is it possible this coronavirus has been in circulation in the US for a time already, and we are only now seeing cases because we are testing for them, when we were not beforehand?

Please forgive if this question has been asked previously.

On a lighter note, I told my colleagues that I was going to quit my job and follow TWiV on their tour around the world. They just said “What’s TWiV?”



Cindy writes:

Hi crew,

Along with being a long time twiX lover, I’m a police officer in a small New England town.  Our resources aren’t as sophisticated as I would imagine population centers are.  

I’m usually the only officer in my town when I’m working and I get dispatched to every emergency medical call.  

For a typical emergency, say heart attack, I would get radioed about the situation at the same time as fire/rescue and will drive right there.  The on-call EMTs would drive to the fire station, get their gear and the ambulance and drive to the call.  

I arrive alone to the medical call usually 10-15 minutes prior to them.  I carry a small O2 tank with bag valve mask, nasal cannula and nonrebreather, an AED and a few tourniquets and some Narcan.  

PPE is non-latex gloves and a Glock-22  :^) 

I’m only a couple of years on the job, but doing chest compressions already resulted in a save for me along with multiple times I kept people with opioid overdoses breathing until medical arrived.  

I’ve also provided care to young and old dying people who probably had contagious disease. I’m left to do my best and maybe use some hand sanitizer before I get back in my cruiser. I don’t even have access to a clothes washer at the PD, so uniforms are coming home to get washed.

In an ideal world, all smaller PDs would be prepared for this outbreak, but we certainly are not.

What should I plan for as far as calls?  I imagine a lot of struggling to breathe and nonresponsive with a pulse?

Other than probably being completely horrified by my situation, is there anything you recommend I do to protect myself? To protect the next person I go help after?

Am I wrong to be kind of resigned to the idea that I will be exposed and will just have to deal with that and try not to be a source myself?



Nikolaus writes:

Dear Twivsters,

My name ist Nikolaus Westenthanner, I am a GP from southern Germany and the Corona-Virus Pandemic brought me to your podcast. At first I want to thank you. It is a pleasure to listen to you. I go to work by bicycle every twice a day and so I have about 40 minutes of time to listen to all this important information. By the way. We have about 5 degrees Celsius and mostly cloudy weather conditions.

My Question is about the testing procedure. I don’t really know how this RT-PCR thing works and today I got a text which said that it is possible that there are a lot of false positive test now in Italy and Germany. In this text they speculate that all these tests do not use a specific SARS-CoV-2 test kit but a more general coronavirus test kit for this RT-PCR. The conjecture is that it is not possible to produce so many specific test kits for SARS-CoV-2 in such a short time. 

What do you think about this?

Thanks and keep on twiving

Brenna writes:

Hi TWiV Team!

Long time listener.  I started in academics and after a PhD and a Post doc I went into Public Health.

I hear in the podcasts that there isn’t much information on the current COVID-19 (or, as I prefer to call it SARS-CoV2) test.  So let me give you the background:

The CDC originally came out with a Real-Time Reverse-Transcription PCR (RT-RT-PCR?).  It had 3 targets, all to the N gene. Why the N gene when everyone else uses the Spike?  Your guess is as good as mine.

They sent the test out to 99 different Public Health Labs (PHLs).  Of the 99 only 5 could make the assay work. 94 labs could have the N3 probe react to something in the HSC late in the reaction, causing a late positive Ct for the HSC for probe 3. 

The CDC said they were going to replace just the N3 primer/probe set, but that the other 2 should be good to go.  A week passed. The CDC was still working on it. Were they going to change the sequence? No one knew what the problem was. However, in situations like this laboratories cannot just adjust a protocol.  We are required by CLIA, FDA, and every other alphabet soup agency to do the test EXACTLY as it is written.  

A second week passed and in a surprising turn of events the Association of Public Health Laboratories (who work VERY closely with the CDC getting a myriad of assays and programs up and running) wrote a harsh letter to the FDA asking them to loosen requirements for Emergency Authorized Testing.  Days afterwards the CDC said you only had to use the first two N primer/probe sets. They re-manufactured and sent new lots out to all the labs in about a week. And basically we never speak of the N3 primer/probe again.

Testing requires both a doctor and an epidemiologist.  In testing like this there has to be an epidemiologist sign off- a doctor cannot just order the test.  Even with the loosening of the rules there is paperwork that an epidemiologist is required to fill out and approve before we can initiate testing. Granted- a doctor has a great deal of sway- which reminds me of a story.

About a year ago there was a small MERS-CoV outbreak in the Middle East (as there is now!).  It was still flu season. I was working for the Laboratory Response Network in Texas at the time.  The LRN is the lab that hospital labs go to when they can’t rule out a Biothreat Agent. So I get a call after work- does our lab do MERS-CoV testing.  No, we didn’t. Who did? The nearest big city or the state capitol lab. Ok, well they are going to send over a sample that is suspected of MERS-CoV for flu testing and we need to be ready to handle it. 

Our hospital lab was very concerned about taking a potential MERS-CoV sample and running it on their nice, NEW flu-PCR machine.  Understandable, but after several meetings we go through various safety options and decon methods and they are ready. They run the sample and… it is FluA positive. I grab an aliquot of sample and take it back to our lab to do the CDC Flu panel- which generates a type and sub-type.  I run the PCR- A/H3. I later ask the original referring hospital for more patient information- turns out that this patient ALSO had a Rapid antigen Flu A positive result about 12 hours before we even got anything. 

While all this was going on they shipped a sample to the Austin lab to get tested- but, even with it being cold outside, they didn’t pack it in enough cold packs so the sample arrived melted and was considered unsuitable for testing.  So they got a new sample, packed it in dry ice, and flew it BY HELICOPTER to Austin to get it tested. 

All because the doctor said the patient was “too sick for just the flu”.  So after quite a bit of extra effort the sample was finally tested for MERS-CoV.  Where it was found to be Negative. 

My advice to all physicians: If a patient is Flu positive THEY HAVE THE FLU!

As a side note, and you don’t have to read this as I am not interested in fear mongering, 

I didn’t do my PhD on coronaviruses.  Coronaviruses are much like polio in the presence and use of quasispecies to determine pathogenesis.  There are reports of quasispecies playing a role in pathogenesis. There are neurotropic coronaviruses (they are mouse in origin, but they were selected for from a strain that infects the lungs when cultured properly).

So it is quite possible that the quasispecies diversity of the infecting virus and the diversity generated throughout infection can impact intestinal infection as well as neurotropism.

Thanks for the great podcast and if you hear “Ohh!!  Pick me! I know!” its probably me yelling at the podcast. 

elbow bumps, 

Ben writes:

Hi TWiV Team,

On your brief discussion on airplane air recirculation I thought I would bump in and say that while the air is brought in from outside, not enough air is brought in from outside. Understandably it’s expensive to bring in -60°C air and heat it to cabin temperature, and so airlines try to keep it to a minimum. In terms of % oxygen and % carbon dioxide, airplane air is now less fresh than it was when people could smoke on planes, because they brought in much more air to get rid of visible pollution. While the cabin air was obviously more carcinogenic then, I would think less air from outside and higher CO2 could mean greater transmission potential.

Thanks for all your fantastic work, you’re really providing the public with level-headed information in a time of mania.

Regards from a toilet paper deficient South Australia,


No Name writes:

Hey guys not really a question but more of a comment. There were a lot of questions about masks and their utility on episode 590. While I understand people wanting answers to these questions, at this point it’s largely academic as they are just not available anywhere. Also, as Rich pointed out a lot of people are probably not going to use them correctly like the woman he was sitting next to on his recent flight. 

To make matters worse this lack of availability is probably going to have an impact on HCWs and first responders, which for obvious reasons is not good. Something to think about, at least from my point of view. 

Jody writes:

Greetings, TWiV High Council! 

First of all, a brief but tremendous thank you for reading and responding to my email a few weeks back. I can’t begin to express the heart-bursting joy I felt at hearing your thoughtful advice and consideration on how to tackle getting started on my ID career mid-life. I now have a juicy list of docs in Seattle to target and will be doing so this year, and feel genuinely bolstered by your encouragement. Also I would like to give a shout-out to Matt Daugherty (now of the Daugherty Lab at UCSD) who sat in my backyard five and a half years ago telling me about Chikungunya over beers; when he saw the light in my eyes and the froth build at my mouth to know more, he said, “you know, there’s a podcast you might want to listen to.” And here we are today.

As a virology enthusiast, this is an exciting time. All of a sudden EVERYONE wants to talk about viruses, whereas I usually am allocated only a few minutes of each conversation with friends and husband to bore them with my giddy ramblings about what I recently learned on TWiX or read about in whichever history of disease book I happen to be currently devouring. The exception is my 7-year-old daughter, who regularly asks that we stop reading 15 minutes early each night so that we can talk about viruses (she wants a new one each night; I have some more reading to do!). A professional podcaster friend actually asked me to meet up this weekend so that I could help her prepare for a coronavirus-focused episode she was recording the next day with her cohost in Italy; we spent almost 4 hours talking viruses in general and SARS-CoV-2 in particular, and I shared scores of articles/papers/reports harvested from your episode links over the last month. It was a hoot. She had just gotten off a plane and kept coughing and sneezing; her husband and I did our best to maintain a meter’s distance from her (though our beers surely were collecting respiratory droplets), we debated whether she should wash her hands before or after using the ketchup (both!), and we all tapped feet and elbows lovingly when we said goodbye at the end of the night. 

As you scientists like to say…”So.” So — as the outbreak situation in Seattle is rapidly evolving and my friends/family/spouse are all coming to me (not a virologist or epidemiologist or public health professional of any kind) and asking “What should we do?”, I thought I would write to you with some updates about what is happening here and ask: “What should we do?”

Since learning that experts believe that the virus has likely been circulating undetected here in Washington state for over a month, people have gone into action. Currently there is a bit of an apocalypse-cum-festival atmosphere in the city. For the last four days or so, people have been packing Costco and local grocery stores like it’s the day before Thanksgiving or the Super Bowl, and by 3pm the shelves are cleared of canned food and toilet paper. Our local Trader Joe’s reported record sales this past weekend and every drugstore in my neighborhood has signs taped up in the window saying “We are SOLD OUT of face masks and hand sanitizer.” Everyone is very concerned and prepping like crazy, but laughing and joking at the same time. Yesterday I had so many lighthearted conversations with chipper strangers, about how many boxes of mac ‘n cheese would last 30 days, which wine might go best with the apocalypse, etc. People are actively preparing but decidedly not panicking. 

That said, our governor and county executive have both declared states of emergency. Large companies like F5 and REI have closed campuses temporarily, and Facebook and T-Mobile have taken measures to limit who is coming through their doors. A number of schools have closed. King County is in the process of buying a motel to house patients who need to be isolated, and the city is setting up modular units to treat and house the infected among our homeless population, which is the third-largest in the US and numbers over 5,000 people. A local immigration office has closed for 14 days due to an exposure, and scores of firefighters are in quarantine after being exposed at the Kirkland care center that has become the epicenter of our local outbreak. 

I have been following all along in real time as you have speculated about possible outcomes and looked at local and national containment efforts with a critical eye. So my big question for you is — now that it seems clear that there is an infectious prodrome and there are likely perhaps hundreds of asymptomatic people (or very minorly symptomatic people who think they have a cold) out shedding virus and coming into contact with scores of others every single day, what steps should we be taking to stop this outbreak in its tracks? I’ve heard you criticize quarantine and travel bans, but I have also read that early identification, quarantine, and citizens changing their daily behavior have been effective in stopping other outbreaks. Our governor in a press conference yesterday urged social distancing and suggested that working from home when sick could be seen as a “patriotic act”; I like this idea but it is obviously a luxury of an office worker and not something that can be done if you’re in a service or manufacturing job that you will lose if you don’t show up. And only working from home while sick does not solve the problem of the asymptomatic or mildly symptomatic shedder who might be working at a school or riding a bus or working out in a gym every day. 

So — if this continues to spread, should we close schools for a month? Should everyone shelter in place for a month (which is what the city is planning for, with their hoarding of canned beans and TP)? Should every business that is able ask their employees to work remotely? How does one stop a virus like this that often causes such mild symptoms from spreading in a big city? Will following the advice of washing our hands and cell phones and not shaking hands keep us all safe, or is this like Bush’s Homeland Security telling us that all we needed to protect ourselves in the case of a biological or chemical terrorist attack was duct tape and plastic sheeting? 

On another note, I’ve really enjoyed hearing the first hand accounts from your Chinese listeners. My husband last night told me that he had just had a call with his colleagues in Shanghai, and they shared the measures they are taking currently, which include working in shifts to limit how many people are in contact with each other both on transit and in the office, working from home as much as they can, calling into group meetings in the office even when they are there physically (they are no longer meeting in conference rooms at all), and doing temperature checks on the way into the office each day. He also told me that one of the main trade shows his business attends and exhibits at, the International Housewares trade show or IHA — which usually draws about 60,000 people to Chicago each March from all over the world — was cancelled. The long ranging effects of this disease on the environment and the economy will be interesting to watch.

I’ve shared a number of articles below, including the potential effects of this situation on Chinese pollution levels, how Chinese restaurants in Seattle are suffering, and an article that explains that the Seattle Flu Study (a new University of Washington group that sends swab kits out to the public — i have 3 of their boxes sitting next to my desk in fact, and my daughter hates doing the nose swabs but loves playing virologist) played a role in identifying the second Washington COVID-19 case. 

And lastly — there’s been a lot of talk around here about how this virus might play out differently in place like Italy, where your job is guaranteed even if you stay home sick and healthcare is socialized, vs. the US, where you can lose your job if you don’t show up and where many people do not have access to healthcare or the means to pay for it. 

Thanks as always for your commitment to truth seeking and truth sharing and for always being pedantic and entertaining. It’s 52 degrees and cloudy here in Seattle with a chance of coronavirus. Be nice to Dickson.


Jody   // L O S T    L A B O R A T O R Y   //

– – –

Dramatic fall in China pollution levels related to coronavirus

A coronavirus recession could be supply-side with a 1970s flavor

Seattle area school closures

Planning for treating and housing the homeless population

Businesses roll out strategies to cope with coronavirus

Growing fears hurting Chinese businesses in Seattle area

Coronavirus may have spread in the U.S. for weeks + Seattle Flu Study

Just for Kids: A comic exploring the new coronavirus

King County buying a motel to house isolated patients

First days at the heart of an outbreak

Fears over coronavirus exposure close immigration office in Tukwila

Our lack of paid sick leave with make the coronavirus worse

25 firefighters and 2 police officers in quarantine

Chicago housewares tradeshow canceled over coronavirus concerns

Kevin writes:

Hi Vincent (and friends),

PPE has been a recurrent topic on your show recently, for good reason. I was very interested to hear of the article you’ve been citing by Radonovich, et al. that showed little difference in effectiveness between N-95s and surgical masks in preventing occupational exposure to flu in healthcare settings.

I thought the attached article might be of some interest to you as well, considered in light of the Radonovich study, as it shows how much performance can diverge between idealized/controlled conditions and the real world. As you have been emphasizing, N-95s are designed to provide protection from airborne droplet nuclei, whereas surgical masks are designed to be fluid barriers only. This study demonstrates the magnitude of the difference in protection factors between the two (along with makeshift coverings), while showing that surgical masks do provide some very limited benefit against airborne exposure if used properly. It also explores the reduction in particulates generated when masks of various kinds are worn by a sick person (in this experiment, a mechanical head), which is surprisingly low, but better than nothing.

Best regards,

Kevin McGhee (Yes, the same one from your IBC a few years back. Greetings from Auckland, NZ, where it is a cloudy 23 C.)

[Note: the FFP2 masks tested in the attached study are the Dutch equivalent of N-95s]

[In case attachment doesn’t work: van der Sande M, Teunis P, Sabel R (2008) Professional and Home-Made Face Masks Reduce Exposure to Respiratory Infections among the General Population. PLoS ONE 3(7): e2618. doi:10.1371/journal.pone.0002618 ]


Kevin McGhee, CSP, CHMM

Associate Director, EHS & Compliance

New York Genome Center

David writes:

Fascinating report you mentioned that many different respiratory illnesses have fallen in Hong Kong in 2020 compared to 2019. If it has been written up anywhere, I would be interested in a link. I will note, however, that it may be hard to attribute the broad decline to any specific interventions. As it turns out, I was in Hong Kong for the month of February. Tourism was already down as a result of the political instabilities that have been on-going since last summer and absolutely cratered with reports of the viral outbreak in Wuhan in January. Hotel occupancies were well below 50% and all of the US carriers canceled all flights between the US and Hong Kong in early February (fortunately we were booked on Cathay Pacific). Memories of SARS are still fresh and Hong Kong reacted early and aggressively to the Wuhan outbreak. Schools, museums, cultural centers and many government offices were closed, although most businesses remain open. Everyone  was wearing surgical masks on the street, hand sanitizer dispensers were ubiquitous, and workers could be seen regularly disinfecting elevator buttons, door fixtures and escalator handrails. Hotels and high rises had people posted at the entrance and were measuring the temperature of everyone entering the building. And yes, everyone was washing their hands frequently. So I’m not surprised that the incidence of respiratory viruses has fallen broadly, but it’s hard to say which specific intervention did how much.

It’s important to emphasize that the infectivity of a virus, R0, is not an intrinsic feature of the virus but also depends on the environment and social behaviors. R0 is a statistical measure of how many people on average a case infects. If people practice disciplined hygiene and social distancing the number of new infections will on average fall. Hong Kong and Singapore have both seen slower rates of growth in COVID19 cases compared to other countries outside of mainland China. Non pharmaceutical interventions (NPI) can make a big difference, and right now they are all we have.



P.S. On a previous show you identified me as a Professor of Human Genetics at the University of Michigan. I was in fact a  professor of Human Genetics, but that was more than a decade ago and I have since left to pursue opportunities in biotechnology and drug development. I believe Kathy and I have met in the context of graduate education committees (PIBS), small world. Go Blue!

David J States MD PhD

Ann Arbor, Michigan