TWiV 591: Coronavirus update with Ralph Baric

March 15, 2020

Ralph Baric joins TWiV to dissect the coronavirus pandemic caused by SARS-CoV-2, including discussion on community spread, asymptomatic infections, origin of the virus, transmission, vaccine development, and much more.

Hosts: Vincent Racaniello, Dickson Despommier, Alan Dove, Rich Condit, and Brianne Barker

Guest: Ralph Baric

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Intro music is by Ronald Jenkees.

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27 comments on “TWiV 591: Coronavirus update with Ralph Baric

  1. Cameron Rogers Mar 15, 2020

    Hi TWiV team,
    Asymptomatic cases are often IMHO commonly children. It would appear that children when infected often don’t progress to symptomatic disease or at the most mild symptomatic disease but have the potential of being asymptomatic carriers. There seems to be some debate here in Australia in regards to how long before the development of symptoms a case could be infectious. Studies that I have read put it out as far as 3 days, our authorities seem to think that there is no risk of being infectious over 24 hours before the onset of symptoms. I would like to know what the team thinks.
    On another topic, don’t you think that the Diamond Princess, where they knew exactly who was and wasn’t infected is a good experiment in determining the case fatality ratio. There were no cases missed, everybody was tested on that ship, so we know the actual case numbers and the actual fatality numbers, of which I have read were 8 fatalities from around 700 cases. Which should result in a CFR of 1.14% assuming none of the remaining 15 serious / critical patients pass.

    Great podcasts team.

    “Like previous epidemic coronaviruses, “SARS-CoV-2 [seems] to cause fewer symptoms and less severe disease in children compared with adults,” according to the review by Petra Zimmerman, MD, PhD, of the University of Fribourg, Switzerland and Nigel Curtis, FRCPCH, PhD, of The University of Melbourne, Australia. They summarize available evidence on coronavirus infections in children, including COVID-19.
    “There is some suggestion that children are just as likely as adults to become infected with the virus but are less likely to be unwell or develop severe symptoms,” Drs. Zimmerman and Curtis write.”

    • Russ Holmes Mar 16, 2020

      Note that the cruise ship occupants had a much higher average age than the general population. Hence the data suggests a real CFR of significantly less than 1% overall.

      • John Coogan Mar 19, 2020

        Once a patient thinks they are over the Covid-19 virus or is told by a professional healthcare provider that they are, can the patient still be contagious for a period of time and what would that period be?

      • Cameron Rogers Mar 19, 2020

        Russ I am aware of that. Although old they were fit enough to take a cruise and they were detected early and had the best of medical care. What we did see from Petri Dish Princess was actual cases to actual cases that resulted in death. I don’t think we can count on a hugely lower case fatality ratio than that. It is a good statement though and I am quite aware of what you are saying. The downside is though, age isn’t the only comorbidity, obesity can be too and all the diseases that are associated with that.

        Cheers Cam

  2. Hey, I wrote a timeline + summaries for the segment of the show Dr. Baric was on here:

    Please give it a once-over if you have the chance as I have only been following virology for ~2 months and I do not want to spread any misinformation. I wanted to make something more accessible for the people who might struggle with the terminology or the implications of things discussed.

    Thank you for the fantastic job so far, I’ve intently listened to every podcast you’ve put out since the first one with Dr. Baric back in January!

  3. Oooo… Prof. Baric’s speculation about the need for passing a sars-like virus through childhood brings back recollections of Prof. Racaniello’s discussion of the polio epidemics – caused by changes which prevented previously-normal childhood consequenceless infections.

  4. Patricia Graham Mar 15, 2020

    Wonderful information! A true public service and we are all gonna be expert virologists soon as well as epidemiologists.

    That said, what about using copper shavings in masks for providers? Jut grind that up and use it in mask production. I want a copper mask myself,

  5. Steven Bachenheimer Mar 15, 2020

    Re the Chinese (and for that matter other countries like Singapore’s) efforts to limit community spread, there’s a fine line between “draconian” measures and best public health practices. These measures did result in quickly reducing the rates of new cases. Let’s keep our eye on the goal in this instance.

  6. Again – N95/99/100 versus “face mask” (surgical mask)

    • profvrr Mar 15, 2020

      It doesn’t matter. Both are unavailable. If it mattered we would specify.

    • xavier Mar 16, 2020

      We are using N95 models 3M™ Particulate Respirator 8210, N95 160 EA/Case ever with face protection


    Update the state of New York is investigating Alex Jones for making claims online that his products can cure COVID-19. Note as of 2020 COVID-19 Vaccines are still waiting for FDA approval.

  8. Loren Annikki Launen Mar 16, 2020

    Dear TWIV team
    Thank you for your wonderful work! Could you post a link to the Hong Kong data on reduction/shortening of influenza season due to public health measures aimed at reducing COVID-19 spread as described in TWIV 590? I looked online, but only see mainstream type media carrying that information, I cannot find the original source of the graph shared in the media or discussed by Dickson. Could you add it to the shownotes? This information is so important to share broadly because it tells us we CAN do something helpful simply and inexpensively. Apologies if I am just not finding it.
    Thank you
    Loren Launen


    I am wondering about this one. I wonder if the alleged plague report from China back in November 2019 was the point of origin for the now known COVID-19. I remember this was brought up on TWIM but that was before we knew anything of COVID-19. It showed a diagnosis of pulmonary at the time too.

  10. Dave J Mar 16, 2020

    Can you please clarify the super spreader anecdote about the gentleman who walked through the ER in Canada and infected 19? That is being passed around the internet as a SARS-COV-2 incident.

    In my interpretation of Dr. Baric’s statement, it was ambiguous whether he was speaking about SARS or SARS-COV-2, but I think SARS.

    Or at least that’s really what I wanted to hear.


    • Cameron Rogers Mar 19, 2020

      In my humble interpretation he was talking about the current outbreak. That being said I am still looking for evidence to back up his story and would be grateful to anybody who can find it. Not that I doubt Ralph Baric, because if anybody knows his stuff, Ralph he is the man on coronaviruses (just after Vincent on viruses in general) but I would love to see a paper on it.

  11. Syed Mazher Mar 16, 2020

    Very thank to your group! Appreciate what you do

  12. Donald Drumph Apr 14, 2020

    Since when did Negative Controls that happen to test positive all of a sudden become Asymptomatic Carriers???