Maxim writes:

Dear TWIV team,

As pretty much everyone knows, cleaning your hands regularly with soap or hand sanitizer is as far as I understand, the best way to prevent yourself from catching COVID-19 and a plethora of other diseases.

However, I was wondering if bar soap is as effective as liquid soap in killing viruses that may be on your hands, especially in the context of the COVID-19 outbreak.

I also wonder if bar soap “retains” microbes and viruses after washing your hands with it.

The preface of this question is that my father only uses bar soap and refuses to use liquid soap, a remnant of him growing up in the Soviet Union where liquid soap was a rarity, and his stubbornness in regard to change.

Right now the weather here in the Region of Valencia, Spain is a sunny 22ºC / 72ºF.

Kind regards,


PattiMichele writes:

Please always differentiate in your conversations between “face masks” (surgical masks) and N95 masks. There have been many recommendations that N95’s do protect the wearer. here in the US, 3M N95 masks are available (before covid-19) even in Home Depot hardware store for protection against dust. So the technology for good SARS-like protection has been widely (cheaply) disseminated. Could this potentially have impact on epidemics? Given the numbers game, I should think so. This is important given the need to reasonably preserve the global economic output.

Kiana writes:

Thank you very much for your highly educational podcasts. They are utterly invaluable. My 12-year-old daughter, Melanie, who listens to your programs regularly, has a question for you: Greetings, I would like to know if there are any projections as to the probability rate of mutation of the SARS-CoV-2. Will most infected humans, who recovered, develop immunity to this virus for the near future? Or is it predicted that the virus mutates so rapidly, that immunity, even for the near future, is not likely? In such a scenario, could a previously SARS-CoV-2-infected person get re-infected in the near future? Thank you very much in advance for reviewing my question.

Matt writes:

Thanks for the superior podcast, which is warmly appreciated.

It is a glorious, pristine morning in these verdant Northern California foothills, with a temperature of 52 degrees.

I note a continued emphasis on handwashing recommendations for the general public, including your New York Times article discussion last week describing its effectiveness during the Chinese SARS outbreak in public schools there.

I propose the following:

Let’s supplement the recommendation for diligent handwashing to include facewashing as well, namely careful cleansing of the nostrils, lips, tear ducts, and ear canals, which are the routes through which most infectious agents enter the body.

I think we should stick with CDC recommendation of coughing into elbow, washing hands, and not touching face.

Our repeated emphasis on handwashing overlooks the fact pathogens rarely enter the body through cuts on the hands, but rather make us sick after entry through the mucous membranes of the face.

Such a recommendation for facewashing should include specific language that it must always be preceded by diligent handwashing to reduce the risk of filthy hands washing the face making matters worse. 

However, if the hands are properly cleaned, facewashing offers a low-cost, non-trivial path to improved outcomes during outbreaks.

Facewashing also offers a collateral benefit of mitigating public panic during outbreaks, of particular importance in this age of social media.

Anecdotally, I have used this approach of careful facewashing after diligent handwashing following episodes of extreme exposure to very good effect over the last seven years. In contexts where where most fellow office members and friends are hobbled by various bugs, I get sick less frequently, and when I do get sick, it is less severe.

In summary, facewashing with clean hands is an important new tool in public health. 

Thanks again for setting the gold standard in medical podcasts and I will become a Patreon subscriber later this week.

Vic writes:

Dear All,

This is Vic, the Ship’s Agent in Kristiansand, Norway.

First of all, of course I’m still listening!  I think you could say I am a TWiV “Womb to Tomb” listener. 

Secondly, what’s happening in the Cruise Industry in the Time of Coronavirus?  The answer would be…it doesn’t look good. During the past 48 hours, one of my colleagues was the agent for a German cruise ship, the AIDA Aura, which had a port call in Haugesund, Norway.  On Monday, the ship arrived in Haugesund and the passengers were allowed to go on land for tours of the local sights. During the day, two passengers received news from Germany that an aquaintance of theirs had tested positive for coronavirus.  When they returned to the ship, they reported to the ship’s medical personel that they had had contact with a known carrier. Following this, these two passengers were quarantined in their cabin.  

The ship then contacted my colleague, the ship’s agent,  and informed her that they might have infected people onboard.  She informed the local medical authorities and one of their staff doctors went on board and took samples from the two quarantined passengers; these were sent to the pathology department for testing.

In the meantime, all passengers and crew were confined on board the ship.  No one was allowed to leave the ship, and the ship was not allowed to leave the pier until the test results came back.  My poor colleague now had to handle a storm of phone calls, emails, and messages from the media and all of the consulates of every nationality on board.  

Yesterday afternoon at 4:00 PM, the Haugesund medical authorities held a press conference where they announced that the testing showed no sign of coronavirus infection.  The two affected passengers were allowed to leave the ship and fly back home. However, the airlines would not allow them to travel until they could provide “Fit to Fly” certification from Haugesund Hospital, which they subsequently received.  The ship was then allowed to continue her voyage northward.

According to my colleague, if the tests would have been positive, then all passengers and crew who had been in contact with the two infected passengers would have been removed from the ship and placed in quarantine.  This would indicate that the Norwegians have learned something from the mistakes made on the Diamond Princess in Japan.

In general, the cruise lines are reacting to the current situation by requiring anyone, including us, the ship agents, to submit a recent travel history and have their temperature taken prior to boarding.  I am sure that the already vast number of hand sanitizing and washing stations in the ships has expanded. They are also plating and serving all meals so no passengers are grazing along the buffet lines. However, this may all be moot if people get freaked out at the prospect of spending a week in very close proximity to potentially infected fellow travelers.  We have not gotten any port call cancelations as of today, but I would not be surprised if we begin to hear that many, many ships will not be coming to Norwegian waters this season.

Love the show!  Keep up the good work!



Glenn writes:

Love these podcasts. As a layperson with zero tolerance for 2nd hand spinning of data and “facts” by the main stream media, this hour (+ or -) is invaluable as are the notes and links supplied for me to peruse on my own.

Thanks for addressing the G.I. complications in this episode.

My question is :

Why are masks NOT mentioned in the “Safe Practice” guidelines or endorsed by you (panel) when it seems that droplets are the primary source of transmission, when hand washing and prudent hygiene are being utilized ?

I get that the virus particles themselves can easily pass through the mask, but just considering a benefit on a particle to pfu ratio basis, it seems that restricting propagation to any degree would be beneficial… if not in this case, then why not?

Thanks in advance,


Yukie writes:

Hello, my hero/heroine scientists! 

I am Yukie writing from Japan and was also one of the first writers to TWiN. If you remember, I am a freelance translator mainly translating adverse drug event/reaction reports from Japanese to English for foreign pharmaceutical companies. 

Thank you very much for keeping me updated on COVID-19 (what do you all think about the name, by the way?).

In Japan, face masks have vanished from drug stores and are hard to find.

Demand>Supply!!!!!. But, I can just calmly wash my hands frequently because I am your listener!

The latest news (as of 12-Feb-2020) talked about a quarantine officer on the cruise ship “Diamond Princess” tested positive for COVID-19. I advertised TWiV with “#DiamondPrincess” on twitter. I hope things are going to calm down without any repercussions for the Tokyo Olympics/Paralympics!

Looking forward to the next episode!

Best regards,


Tony writes:

Hi TWiVers,

I just came across the attached paper (which I think sucks, but that\s beside the point) and noticed a high degree of antibacterial use despite a low incidence of bacterial comorbidities in the cohort. In fact, the rate of antibacterial administration outstrips the rate of antiviral administration, although this cohort may have been studied before the causative agent was definitively identified.

Are you aware of any research investigating the effects of antibiotic-mediated microbiome disruption on COVID-19 pathology? China’s long been a known hotbed for misuse of antibiotics and it seems within the realm of possibility that populations with lower educational attainment could gravitate toward antibiotics overuse could affect during an outbreak of a novel disease. in potentially impactful ways.


Tim writes:

Dear TWiV Crew,

Thank for you providing such an informative and accessible podcast. I always learn something new and interesting!

It is -6 C and cloudy here in beautiful Madison, Wisconsin this morning.

I saw someone speculate that ADE due to exposure to one of the “common cold” coronaviruses might facilitate SARS-CoV-2 infection. I can’t evaluate the plausibility of the hypothesis as I have no prior understanding of ADE. If you have time on an upcoming episode, a brief discussion of what ADE is and what viruses are advantaged by it would be interesting at least for me.

Thank you again for your wonderful podcast and keep on TWiVing!


David writes:

Hi Again,

While we are on the subject of coronaviruses and their interactions with the immune system, persistent viral shedding by a significant number of COVID-19 survivors is being reported, e.g.

Would be very interested in the group’s thoughts on the implications of this finding for vaccine and antiviral development, and what underlying mechanisms may be involved allowing the virus to evade immune surveillance. Do coronaviruses persist in protected immunological spaces such as the eye and testis as does the Ebola virus? What other mechanism might be involved?

Thank you again,


David J States MD PhD

Ann Arbor, Michigan

Stephen writes:

Dear TWIVsters,

I wanted to shed a little light on something Dickson mentioned briefly in the last episode. He talked about a story about a whole family he had seen that had died. It sounded like he was worried that was evidence of higher mortality among younger people. However, I think I read recently about the same family in this article: The family in question isn’t a standard nuclear family–a 55 year old movie director, his sister (age unspecified), and his mother and father. While the youngest member is a little on the young side for the highest levels of mortality rates, this isn’t a counter example. In fact, the article also talks about how they could not find a bed in a hospital for the father, and they ended up self quarantining at home which undoubtedly put them at greater risk.



Matt writes:

Hello. I am a tourist in the world of virology who happened upon your podcast while trying to find useful information about, you guessed it, COVID-19.

As best I could follow your conversation in TWiV 588 about The Proximal Origin of SARS-CoV-2, I was especially confused by one of the pieces of evidence presented in support of the virus having its origins “in the wild”, so to speak.

It was said, “So let’s say a human wanted to put a furin cleavage site here, they wouldn’t put the proline upstream.” It was also said that the proline “allows the addition of o-linked glycans” and that “the sugars act as a shield to the immune response.” Again, I knew none of these terms until today so I’m clearly not challenging what you’re saying; rather, I am trying to inform myself. Given that the proline “allows the addition of o-linked glycans” which “act as a shield to the immune response,” why wouldn’t someone insert the proline if the objective is to design a more infective virus?

I should conclude by saying that one thing I’ve learned during my brief voyage of curiosity into this world of yours is that when assessing a virus’s capacity for devastation, it is of little relevance whether the virus was the product of a lab experiment gone wrong (or worse, gone right!) or a free-range, organic virus. I also come away with a budding fascination with virology!

With thanks,


Allen writes:

Dear Twivers,

Hello and thank you for your informative and no-sensationalized information packed geeky podcast.  I discovered you only about a month ago in a search for solid information… so glad I found you. I recommend you often to friends and strangers alike. 

The weather here in Dubai, on this leapday, Feb 29th, 2020 as we approach 1:30 pm is sunny and blue skies at 26 degrees Celsius.  

We have just been told that schools will cancel some after school activities as well as international and local trips as a precaution.  However it appears the malls will remain open :). 

My question is about the graphs that I see often that show total cases and total deaths. They are provided in both linear and logarithmic format.  My question is not about how to read them… but why they are posted this way.  

The scales makes sense in both, but what is the reason for show both?  In terms of how I interpret the data… the actual numbers, it doesn’t really change my view.  Is one advantageous over another for reasons that are unbeknownst to me? 

Thanks and please continue to be the signal through the noise. 

Kind regards,


Eric writes:

Hi Vincent and Go Blue to Kathy!

I’m writing from South Korea where I work as a high school teacher.  It is a hazy 2 degrees Celsius with unhealthy levels of PM2.5 fine dust pollution.

My question concerns government response to COVID-19.  

South Korea is an interesting example as it has the most cases outside of China, but has a democratic government much more comparable to the US.  The spread here was accelerated by transmission within the secretive Shincheonji cult (CNN has a good brief summary here:  Around half the cases here are still linked to this religious group and the large majority are still in the city of Daegu.  I was wondering if you could comment on the following South Korean government responses, how well they serve public health, and whether they would replicate well in the US and other countries faced with similar outbreaks:

1. Opening drive-thru COVID-19 testing facilities (picture and article here:  Is this a good way to reduce the chance of virus spreading in hospitals?

2. Rationing face masks by limiting to two per person per week, with the date you are allowed to purchase limited by birth year and requiring ID and using the drug purchase system to prevent repeat purchases. (

3. Using the cell phone emergency alert system to notify people of general hygiene recommendations and to inform us of the exact locations that infected people recently visited.  (  Personally, I actually received 25 emergency alerts in one day!  They come from both local and regional governments.

4. Maintaining a public website from the KCDC with twice daily updates.. (

5. Using military trucks to spray streets with disinfectant. (pictures here:

6. Ordering all schools closed until March 23rd and limiting/closing other large gatherings.

There are of course many other responses as the government has approached this with urgency, carrying out hundreds of thousands of tests, converting facilities for patients, and even investigating the Shincheonji leaders.  Personally, I’ve been impressed overall with the efforts but I’m concerned that the decentralized US system may not be as focused and worry about what would happen if hospitals become overwhelmed in some areas as has happened in Wuhan.

Also, a specific question for me: since it is impossible to maintain a supply of face masks to use daily due to the rationing and it is impossible to go outside without one as people will yell at me, do you have any advice?  I know it is dangerous to reuse these single-use masks, but does it work if I, for example, use one mask for each day of the week and when Monday comes around again, will any virus from a week ago be dead?

Thanks, I’ve been enjoying your podcasts for years and recommend them to my students who are interested in virology!


Nema writes:

Hi Twiverators! 

I love your podcast. My thought & question is:

Since lung CT scans can be used to diagnose COVID-19, why not do a study of lung CT scans made for atypical pneumonia in January & February 2020, as a way to estimate the current community spread of COVID-19?


Regula writes:

Hi Vincent,

you and your team have probably seen this notice about the improvement of air quality over China before, but I thought it was amazing.

Kind of reminds me of the reports of the ecosystem thriving in the Chernobyl area.

Thanks for everything you do, I am currently in the middle of a marathon training cycle and TWiV is my podcast of choice for long runs. Don’t mind at all that the episodes are 2+ hours 🙂


Kevin writes:

Great show TWiV 589, been looking forward to repeated exposure to rationality. 

Question: On various international newscasts: China, Japan, Germany, UK there are video clips of space-suited personnel spraying great clouds of unspecified ‘fumigants’, usually in outdoor locations. My brief literature search on the efficacy of this practice yielded a few references from an animal husbandry perspective. Is there any precedent or evidence that fumigation has any role in epidemic control?


PS. I will not compare thee to a bat pissing in a cave: “A SHAFT OF GOLD WHERE EVERYWHERE THERE BE DARKNESS.”

Ben writes:

Hi Vincent and Rich and Kathy

I am a relatively new fan of TWiV, writing from my home outside of Philadelphia.  I love the rational science-based nature of your podcast – it’s a terrific resource; please keep it up!!  I had two questions which I’d love your feedback on:

  1. I understand from reading numerous reports that development of a vaccine for SARS-CoV-19 is only a matter of time, and that this could take upwards of 18 months to two years.  As someone who is totally new to the vaccine development process, I was curious about what the underlying reasons are for the duration of this development timeline. In other words, is this a function of capital to apply to the science?  If capital was unlimited (e.g., global scientists and biopharmaceutical companies had as much money as they asked for) would this shorten the development time? If so, I wonder by how much – could it cut it in half? I understand that human trials are highly complicated and take time, but what are other elements in the timeline of development?  I’m very curious to better understand this at a granular level.
  1. Along the lines of question #1, I wonder if there are opportunities for volunteers who want to be helpful in working on the many dimensions of this global health problem.  Are you aware of resources that folks who want to get involved might be able to explore? For example, I have a background in engineering and computer science and decades of experience in data science / big data and would be happy to volunteer my time to help scientists to review data, do data entry, etc.

Thank you so much for answering my questions!!


Emma writes:

Hello TWiV Team!

I recently sent a long-winded email not related to the current coronavirus outbreak so I think it will take you a while to get there. However, I wanted to bring up something related to your most recent episode. 

I would like to respond to the anecdote shared about being offered a facemask by a “perfectly healthy individual.” While these masks of course would not be any more effective for someone with an underlying health condition, it is not possible for you to determine the state of a stranger’s health by a simple look. 

I am 20 years old and have a condition that effects my immune system, but on the outside generally appear healthy. I will likely need to start using a wheelchair soon, but you would not be able to tell this by simply looking at me, since I am usually capable of walking short distances.

While the health status of this individual was not at all the purpose of the anecdote that was shared, I wanted to bring this up with the hope that you could use your platform to share this message. You can not assess a stranger’s health just by looking at them. This is particularly important to remember because people like me who appear young and healthy on the outside are often accused of faking or exaggerating our symptoms.

Thank you for taking the time to read this, and thank you for all the work you do. I hope this is something that my fellow listeners will keep in mind going forward. 

Again, thank you so much for creating this podcast!


Kevin writes:


I’m a new listener to TWiV and I’ve got a question: after our children’s sports competitions teams will line up and all the players will high five each other. According to this:

it appears that high fives will transmit nearly as effectively as moderate hand shakes. Should I bring this up with coaches to try to get them to switch to fist bumps? Or would that be an overreaction?

In case it makes a difference, we’re in San Mateo County, California, one county north of Santa Clara County where there has been community spread of SARS-CoV-2.

Thank you!


KS pick relates to this

Michael writes:

Thanks for your great podcast!!

There’s a community supported websites that are keeping tracking of the transmission in South Korea, and are being utilized by the major media outlets.


(English version is available)

2. (Only Korean language version is available, but there are charts here)

Always enjoying your podcasts!



Maritza writes:

Hi TWiV-Team,

huge fan! Thanks for all the knowledge you provide & insight you give. I’ve always been interested in epidemiology, even though I work in politics now, but I’m planning long-term to move more into public health communications.

A question: How are people who are shedding SARS-CoV-2 but not showing any symptoms able to find out if they are infected, if that’s possible at all without testing? I travel a lot, and the idea that I’m potentially and unknowingly spreading the virus – even if I wash my hands often, try not to touch my face etc – makes me worried for the people I interact with. This tweet by a Chinese reporter in particular made me think about the issue:

Thanks and greetings from Goa, India (currently 32C), where I’m on vacation and where it’s wonderfully sunny.


Thomas writes:

I’m an occasional TWiV listener & of course a more regular listener at times like these. 

Thanks very much for your service to us non-scientists. TWiV has made me much more interested in viruses than I once was. If only my high school science education had been as interesting as you are…

My very simple-minded question: Is it likely that the coronavirus which is causing this pandemic is even now, as we speak, mutating and becoming something different? If this virus is mutating, will new cases of respiratory illness which doctors think was caused by COVID-19 be less capable of being treated with the drugs (such as remsdisivir) that are now being tested? How long does it take for a virus such as COVID-19 to mutate into something substantially different — hours days, weeks?



Seattle, WA

John writes:

Dear Twiv,

HI my name is John a student at SUNY albany, a former student of Cara Pager”s cell bio class. I was wondering how many of the current coronaviruses are infectious per 100 virus “cells”. If you are exposed to the virus, like inhaled a sneeze or touched your mouth after touching someone with the virus, how likely the virus will surpass your immune system and cause the disease?



Steve writes:

Hi twiv-cast,

I have a question for you. You’ve mentioned a few protease inhibitor‘s as possible antivirals for COVID-19, and I understand the traditional Influenza antivirals would probably not be effective since they are neuraminidase inhibitors but what about the newer anti-flu medication Baloxavir or Xofluza, since  this is an RNA polymerase inhibitor?

Thank your for your passion and all you do.


Steve Shroyer MD

Cookie writes:

You mentioned on your last show – when discussing the Corona virus transmissibility- to keep 6 feet between you and a visibly sick person….are you suggesting we bury the sick person?

John writes:

I have relatives who work in emergency rooms, so I have concerns about his 

their safety in the case of a pandemic coronavirus.

I had read about passive antibody in college, and found this reference on it.

Is the use of passive antibody, so called horse serum, (although its probably bioengineered these days) still something that people do for situations like pandemic flu or coronavirus, where there is no vaccine available. Would passive antibody work?

Adam writes:

Hi TWIV team,

The singaporean government has produced a fantastic data dashboard for Covid-19 cases in Singapore. I am particularly impressed by the information provided on each case and the graphic showing how they are connected.

The actual statistics, and your podcast, are some of the very few places reporting without needless hysteria.



P.S Weather in Newcastle, Australia, is cool and wet. It is a comfortable 22C and we have had a drizzle of a couple of mm of rain today. Everything is green again after being brown two months ago.

Rebecca writes:

Group home residents are well known to be especially vulnerable to transmission.   I have seen no guidance offered for reducing risk to residents. I have seen long term care facilities addressed in general, but usually in the context of a discussion of risk in healthcare facilities. 

Many group homes for people with mild to moderate intellectual disability are not healthcare facilities.  The residents of group homes have high rates of diabetes, asthma and obesity. Many group homes are overcrowded, with residents doubling up in bedrooms designed for one adult.  Staff are underpaid and are not adequately insured. Adults with Down Syndrome are especially vulnerable to pneumonia and in general are thought to have reduced immunity compared to the general population.  

What criteria can guardians of high functioning adults with developmental disability use to decide whether to bring their loved one back home with them to ride out the coronavirus?  At what point would bringing a resident home not be considered over reacting? I’m asking because our 29 year old daughter with Downs lives in an overcrowded group home. My husband and I are searching for criteria to help us decide when it is reasonable to disrupt her routine and bring her back home to reduce her risk of infection.   She lives about a 45 minute from recent cases in Illinois. Do we wait until there is widespread community transmission? Or should we act much sooner?

Todd writes:

Twiv team,

Good afternoon from Japan.  It is currently 57 degrees F and mostly cloudy.  I wanted to reach out and say THANK YOU for all you are doing in keeping up with COVID 19 as it continues to evolve.  You are doing a tremendous public service, and it is greatly appreciated. Saying thank you does not do it justice.

For context, I am in the medical field here in Japan, and we are doing our best to stay on top of the facts as this situation continues to change.  Your subject matter expertise and grounded analysis is desperately needed so we can give decision makers good advice. This allows them to make informed decisions and keep the community apprised of the ongoing situation.  Many of us are going from meeting to meeting regarding COVID 19 and thus can’t devote the necessary time to keeping up with the constantly changing landscape, and without your expert team continuously reviewing the literature and giving it a critical peer review, we could not keep up and give our decision makers the input they need to do their job.  THANK YOU! Much of what we are combatting at present is misinformation and speculation, so what you do is a great enabler to all of us in doing what is right for our team and our community. We have had a series of town halls to engage the public, and for my piece, I have used the information you provided to inform our team members about the virus and how this compares to SARS and MERS. 

On a personal note, I enjoy your podcast immensely and it allows me to stay current on virology even though I can’t be at the bench doing what I love, virology research!  I have also enjoyed hearing former colleagues on your show, like Dr. John Dye and Dr. Gustavo Palacios. I worked with them at USAMRIID, the US Army Medical Research Institute of Infectious Diseases, prior to my current job, and I look forward to working with them again when I return to USAMRIID this summer for my next assignment.  I hope to meet you all at ASV this June, COVID 19 permitting, and sincerely wish to thank you in person.

Keep up the great work and thanks again.



Wink writes:

Could you be overemphasizing hand hygiene? What is the data that the current coronavirus transmits as does rhinovirus? 

Why downplay a surgical mask? For all we know now, they may offer excellent protection. 


EID 2004 reported that surgical masks protected Toronto nurses from SARS.

Wink Weinberg

Hannah writes:

Dear TWiV hosts,

Thank you very much for your recent SARS-CoV-2 outbreak coverage. Here in Ottawa (where it is -4°C and sunny), we haven’t yet had a case, but I figure it’s only a matter of time, and people here are trying to prepare.

Several weeks ago, the Anglican Church of Canada sent out a statement to try and reduce the risk of transmission in churches. The statement emphasised that it is not strictly necessary to drink from the shared cup of wine, and the clergy in my church also drew our attention to existing hand sanitiser stations and encouraged us to try hands-free greeting methods during the Peace (it is traditional to shake hands at that point in the service).

I have been of two minds about whether I should take extra precautions, like refusing to shake people’s hands in church. On one hand, the congregation is quite elderly, and even though SARS-CoV-2 isn’t here yet, there are plenty of other respiratory illnesses around. On the other hand, they all know that I’m doing a PhD in biology, and if they see me taking it too seriously, it could frighten them. As virologists, how do you balance this in your daily lives?

Speaking of other respiratory illnesses, I remember you said that flu deaths are calculated by looking at excess pneumonia deaths in a given year. How will this new cause of pneumonia affect the accuracy of those numbers?