Connor writes:

Hi all, some follow-up to a recent letter/discussion:

Further to your discussion on the last TWiV about the ongoing outbreak of mumps in the US, I want to stress that the mumps vaccine (Jeryl-Lynn strain) used across the US and most of the world, is one of the best vaccines that we have and is incredibly safe with over 50 years of experience. Over this time it has led to a ~97% reduction in cases of mumps and has near-eliminated associated hospitalisations for complications such meningitis, encephalitis, and even the very painful orchitis. However, outbreaks continue to occur and there have been particularly large ones in 2005/6, 2009/10 and now 2016.

The reason why we are experiencing outbreaks of mumps now, which includes those immunised with two-doses of the MMR vaccine, is likely a consequence of multiple factors, as you suggested. These include: continued presence of unvaccinated individuals, waning immunity, very close contact of individuals and minor antigenic differences between vaccine and circulating viruses (although mumps virus is serologically monotypic, the vaccine strain genotype (genotype A) is considered extinct), which taken together could lead to a ‘perfect storm’ for mumps.

The issue of waning immunity or secondary vaccine failure is complicated: perhaps the vaccine is not as protective as it could be or there is little boosting of natural immunity as the wild-type virus circulation wanes. While the effectiveness of a third dose of mumps vaccine is not clear ( ) one strategy would be to generate a completely new vaccine against the mumps virus that provides stronger, more durable protection against disease while remaining safe. There is a precedent for this because infection with wild-type mumps virus provides near-life-long immunity against mumps. Of course, this comes with a cost in terms of disease and getting the balance right is essential.

There is so little understood about mumps virus pathogenesis and immunity that designing a vaccine rationally – that is both efficacious and safe – would be very challenging. For example, we do not know the viral and host molecular determinants of disease; we don’t know correlates of immunity (how important are antibodies compared to T cells, for example?); and we don’t know very much about the fundamental biology of the virus (in terms of tropism, pathogenesis and transmission).

This is in part due to a lack of model systems on the virus and host side. I aimed to address part of this disparity as part of my PhD project in the Duprex lab and established a ‘reverse’ genetics system straight from unpassaged material from a mouth swab from an individual in the 2009/2010 New York outbreak. Modified recombinant viruses from this system and others like it will prove invaluable to allowing us to investigate the critical questions discussed above, which will be important in the development of new vaccines.

For those interested, we published an open access review recently on mumps pathogenesis and molecular biology ( ).

Thanks for the great show ,


Connor in grey, rainy but always beautiful Glasgow, Scotland.

Connor Bamford, PhD

post-doctoral research assistant

MRC-University of Glasgow Centre for Virus Research

Sir Michael Stoker Building


Chris writes:

Dear TWiV team,

The article by Si et al. entitled ‘Generation of influenza A viruses as live but replication-incompetent virus vaccines’ is very interesting although is not so different from the generation of infectious, replication-defective viruses used in more conventional gene transfer or gene therapy studies. The transgenic cells containing cassettes for expression of orthogonal tRNA (tRNACUA), tRNA synthase (pylRS), and an amber codon–containing GFP (GFP39TAG), are not so different from the packaging cell lines used in the generation of retroviral, adenoviral or AAV-based vectors, where replication-defective vectors are desired for safety reasons. Are replication-defective vaccine viruses likely to be more effective at stimulating effective immune responses than a fully replication-competent one ? Only time will tell, but I’d be surprised if they do, as in most cases, the desire is to mimic the effects of natural  infection, albeit with a less virulent strain. At least vaccines based upon the orthogonal approach infect cells, meaning that they possess a distinct advantage over inactivated vaccines. Perhaps they may prove to be particularly useful where an immune response, different from the one stimulated by natural infection, is required….where natural infections fails to stimulate an immune response that is capable of clearing the host of the pathogen, or protect the host from re-infection…HIV for example..

Wishing you all a very happy Christmas and a healthy and successful 2017.



Christopher Ring MSc PhD FIBMS FHEA

Senior Lecturer in Microbiology.

First Year Tutor for BSc Biomedical Science.

Programme Leader for MSc Biomedical Science (Medical Microbiology) and the BSc Applied Biomedical Science programmes. Module Leader for specialist postgraduate Medical Microbiology and postgraduate Biomedical Science Research Project modules.

Department of Natural Sciences,

School of Science & Technology,

Middlesex University,

Steve writes:

Hi Vincent,

Just been listening to the latest Twiv, and was pleased to hear that you were interested in my old sparrow story, and liked the NYC Street Trees‎ pick. (A great way for me to explore the city from here, even. I like popping in to the Smithsonian Natural History Museum tour too. Isn’t the Web, marvellous!).

I just heard you saying about the adverts coming to an end after Christmas, and wondered if you have thought of the ads that are still in the earlier podcasts. I don’t know if having the ads permanently available was part of your deal with advertisers, but it strikes me that having them playing in the archives all the time is not going to encourage advertisers to give you fresh business for your funds.

You might like to look into editing the archived programmes before the backlog of adverts gets great enough to make this a considerable chore.

All the best, and Merry Christmas to you and the TwiX teams, and hoping for 2017 to be a much better year for all. (Perhaps the new movement to bring some fact checking and real truth to ‘news’ on the Web will start to turn things around and herald a new era of ethical behaviour.‎ Perhaps… :))




With a crisp blue, fine Winter’s day just getting under way outside my window.

Steve writes:

Hi again Vincent et al,

I expect that you will be deluged by geology and physics buffs after your changing Earth rotation comments on this week’s TWiV, but I had to do a double take when I heard it being said that the Human race had gained a whole 6 hours of extra day in mere historic times!

Conventional geology has long had it from correlating (no pun intended)‎ radioactive decay with the stratigraphical record, and the daily growth rings on fossil solitary, ‘rugose’ corals, that the planet has only gained about an hour in day length since the Carboniferous period, 350 *million* years ago.

As you can imagine‎, this is well trodden ground in the debate between scientists and Creationists, so it is unlikely that the new story you referred to can be correct. The subject might make an interesting episode (era? ;)) for TWiEVO.

Your podcasts are a very good memory aid for us old guys. 🙂




(Day now even brighter Wintery blue than my last note! :))

Paul writes:


13C in Philadelphia with very high variance and low clouds.

Further to the conversation about authors:

Authors per paper by field:

Michael writes:

I love TWIB, TWIM and TWIV – I grew up in a medical family – it skipped a generation, cuz I turned down Harvard or Yale for a music education. My mom was a nurse, my son is turn. ONE OF YOU has a Limerick contest – most likely expired, but here’s my entry:

There once was a virulent virus

which tried with all might to retire us

We know it’s a pest

But hardly the best

I’m sure that you know Miley Cyrus

Hannelore writes:

Belle jour à tu, francophone, et TWiV(nauts)!

My Pick:


Hello, from FEMA region 5. It’s 13°, Sunny, and the air is crisp, and my cat is meowing.

How are you (to all)?

Thank you for your courage, production, desire to teach, consistency, and communication. Learning the opinions of others, especially if the opinions and people can bring something new for me to observe, has always been a tryst into absolute bliss! Realizing I knew nothing of your topics, but wanted to learn, the natural choice was to go along for the ride, and inform myself as new things cropped up.

Months of listening later, still clueless at times, I feel the ability to locate learning resources growing. Thanks to you, I’ll be returning to schooling with an obsession.

I as well, will be looking forward to an insect podcast.

Perhaps you’d have luck goading Dr. Despommier into recording Urban Agriculture episodes, while fishing.

All my media comes from books, articles, and podcasts. I cut the cord before turning 18. 10 years ago.

Podcasts OPML:

With the utmost admiration, Hannelore S.

___ In reply to Steve’s question ___ 

to filter what’s presented on the web, a bit of aid comes from Web of Trust to flag links. In conjunction with, uBlock Origin, ScriptSafe, HTTPS Everywhere my browsing is a breeze. To cut back on Facebook ads, I only browsed via, and other minimal mobile versions that didn’t do AJAX, or other fancy web-bugs/web-content. WOT puts a colour coded marker by the link, script-safe acts like noscript, and only allowing HTTPS via HTTPS Everywhere prevents some nasty frames from loading.

For more, look at this handy site:

Anthony writes:

Some fifteen years ago, Esther Dyson said that with the rise of the Internet the price of information will tend to zero. Profit is to be drawn from events and products. Ms. Dyson did hold the New York Times up as a possible rule-proving exception. This appears not to be so.

With the New York Times promoting its Store and Events, the paper indeed is — as Esther Dyson predicted — following the example of the Grateful Dead.


# # #

This article appeared in Wired, Issue 3.07, July 1995.

Intellectual Value

– by Esther Dyson

What happens to intellectual property when it gets on the Internet?

. . .

Much chargeable value will be in certification of authenticity and reliability, not in the content. Brand name, identity, and other marks of value will be important; so will security of supply. Customers will pay for a stream of information and content from a trusted source. For example, the umbrella of The New York Times sanctifies the words of its reporters. The content churned out by Times reporters is valuable because the reporters undergo quality-control, and because others believe them – context, again. The New York Times can almost make the truth – for better or worse.

Sarah writes:


I have a question regarding the definition of a zoonotic virus. I am a veterinary surgeon with a PhD in molecular virology from Imperial College London (and of course am an avid TWIV fan having seen live recordings at ASV and the UK SGM!). Having published studies looking at zoonotic viruses in dogs, I thought I had the definition of a zoonosis sorted. However, I am now teaching a bunch of bright second year medical students at the University of Cambridge, who have made me realise the existing definition from WHO – ‘a zoonosis is a naturally transmissible from vertebrate animals to humans and vice-versa’ lacks some details.

Studies report that >60% of viruses have arisen in an animal host and are therefore considered zoonotic. But many of these viruses gain the ability to transmit directly between humans, and then the vertebrate host becomes irrelevant. In the true sense of the word I appreciate that viruses such as Ebola and HIV are zoonotic, but is there a point in virus evolution when this terminology becomes redundant/inappropriate? And when might you say that is?!

Many thanks in advance for your thoughts, and thank you for the ongoing virology enthusiasm!


Heather writes:

Hi Fellas

Although I as far away from the medical field as you can get I really enjoy listening to your podcasts. I am in Toowoomba Queensland Australia and really love the stimulation of learning something new every day. As I left school having flunked year 10 level (was 16 yrs. old) and no direction of what I wanted to do, I surprise myself constantly on how much I understand although mental pictures might not quite match the actual of what you guys discuss. I don’t have much patience for novels or movies but I like non-fiction, factual podcasts that can teach me something I don’t know. You all have such lovely radio voices that make listening so easy and enjoyable. Don’t listen to the complainers about the format of the show and letters you read out as it is just what is required for an unscientific person as myself. In fact it is the perfect fit. I am guessing that 56 years now of life experiences make up for what I didn’t learn in school those years ago. I am gradually catching up on all of your podcasts from the beginning and am up to 134 and enjoying the experience. I have listened when doing my bookkeeping course but that doesn’t work well as I have to concentrate on one or the other. So I usually listen when I am relaxing and at night to mask the sound of the tinnitus which I have had all my life, and learn at the same time!

The best guess is that I got the tinnitus from a severe dose of chicken pox when 18 months hence no memory of not hearing this infernal noise. I get very upset when I hear of parents having chicken pox virus parties to get the sickness “over and done with” for their children. They have no idea that they are possibly ruining their children with future medical conditions with shingles and other conditions. I am at the point that I wear hearing aids to mask the noise and help hear what people are saying around me not because of deafness but the level of the noise in my head. While violence is not good normally I would love to give these dumb parents a good slap.

In an earlier twiv I you mentioned the journalist that investigated Dr Wakefield and a podcast interview that some of you had seen. I would really interested in hearing it if you could possibly put up a link on your website.

Also I am curious as to what year U.S. students start learning physics and biology? I get the impression that it is a lot earlier than here in Australia where it is the upper 1 or 2 years of school just before going to university (college) – I think university sounds a lot better and more grown up!

Keep up the excellent communication work for your devoted followers.

Trudy writes:

Dear TWivVers,

I have a burning question that I have been dying to ask you for a while.  I am a huge proponent of the flu vaccine, and every year, when I get it around mid-October, I announce it on Facebook in an attempt to raise awareness and hopefully motivate others to do the same.  And every time, without fail, I get those one or two comments about how “every single time I got the flu shot I got the worst flu of my life, so, never again!”  These are not necessarily comments by people who believe that it was the flu shot itself that caused the flu.  I know how to address those comments!  Instead, these people truly believe that not only did the vaccine not prevent disease, but it even exacerbated it.  My own mother, who takes care of my children, refuses to get the flu shot due to this alleged experience.  

A few years ago, one person even cited a couple of papers to support his position.  Below, I provided links for these papers for you to look at if you have time:

Although I haven’t read the papers in detail, the data look mostly correlative to me.  One of the papers attempts to attribute the increased risk of disease after vaccination to lack of heterosubtypic immunity, but I still don’t understand how that would contribute to enhanced illness.  The papers do alert to some of the study flaws, such as the bias created by the observational nature of the studies, as well as the lack of randomization.  Although one of the studies attempted to validate the disease case definition on the basis of H1N1 seropositive individuals, they admit that participation in the serologic survey was self-selected and the sample size was small.  It is also speculated that Canadian Aboriginals, a population featured in one of the studies, are genetically more susceptible to severe H1N1 disease.

I do understand skepticism, and I think that’s a healthy way to evaluate scientific data.  But I remain unconvinced that the flu shot causes enhanced disease.  How do I respond to someone who swears that to be the case, especially if they offer their own anecdotal evidence?  

On a side note, on TWiV 417 Vincent asked listeners which other podcasts they listen to.  In addition to TWiV, TWiM, TWiP and TWiEVO, I also listen to Mark Crislip’s Infectious Disease Puscast, an intellectual property podcast called IP Fridays, and a financial podcast called Good Financial Cents.  I have a long commute and tend to alternate between podcasts and audio books.  Every Sunday I download all the new podcasts, and first thing Monday morning, starting with TWiV (OF COURSE!), I catch up on all my podcasts.  Sometime around Wednesday when I’m caught up I switch back to whichever audio book I’m currently listening to.  

Anyway, thanks for all you do!


Ken Stedman writes:

Dear Vincent et al.,

Just wanted to let you (all) know that the first publication (of hopefully many!) to come from a collaboration that got started in response to TWiV 195 (the one with the abysmal audio!) was just published.

I just now realized that we should have added TWiV in the acknowledgements, we will make sure that it happens for future papers from this collaboration. Maybe we can get the publisher to add one retroactively.




Sam writes:

Dear Twivcasters Vincent, Dickson, Kathy, Rich, and Alan,

Thanks again for a great podcast. I learn more about the fantastic biology at the very smallest scale every time I listen.

In addition your perspective on current topics like Zika is invaluable, although I can recommend Patreon to my fellow listeners as a painless but concrete commitment of support

Regarding other podcasts, I’ve got quite a few. Other writers have named Freakonomics and You Are Not So Smart, and they’re great; in that vein I also like Planet Money and Point of Inquiry.

Chemistry in its element, the curious cases of Rutherford and fry, the naked scientists, and planetary radio are some examples of scientists covering science. Nature and science magazines also produce podcasts that showcase research.

In order to sustain my mental well being I am taking a break from the news for the no doubt uneventful remainder of 2016, but many excellent news TV shows such as the PBS News Hour and Washington week in Review are available in podcast form.

For lighter listening than current events, I enjoy a couple of horror fiction casts, the HP Lovecraft Literary Podcast and Welcome to Night Vale.

I’m writing from Tucson and today is expected to be sunny with a high of 74 f and a low of 48.

My app happens to include a flu forecast of sporadic and a medium-high pollen index. I know 74 is probably too much to hope for except for Rich but I hope it’s a nice day when you read this.

Sincerely,  Sam

PS Listener pick? Cell Lab: evolution sandbox. A cell game for cell phones!

Johnye writes:

TWiVetian Titans and Poly-Parisitologists,

Greetings of the Season

The YouTube video might be of special interest to the good Drs. Despommier and Griffin. Wonders of wonders. Recycling, vertical farming or easier, and all the raw material a household can grow for household and personal needs! Such wonder from mycelium.

Johnye  Ballenger

Your “Cambridge Pediatrician” and faithful listener, learner and proud promoter.

9 C; intermittent heavy rains, patchy fog and mist, breezy, with winds from the E @ 21 mph

Brendan writes:

Dear Doctors TWIV,

I am an ICU nurse practitioner (not everyone in healthcare is a “doctor”) with a passion for infectious disease. I have listened to every TWI- derivative with glee and advocated for every healthcare professional (actually, I encourage every non-healthcare professional too) I know to do so as well.

As a side note, I have a four year old daughter (and a son on the way), and it encourages me to hear all of the contributors on your collection of podcasts. Hearing how many of them did not have a straight trajectory to their successful career encourages those of us who take the occasional left turn in their academic or personal life. I do appreciate hearing so many female voices in rigorous science so that I may point them out to my daughter as role models.

Thank you for your time and devotion to your subject.

I have a truly enjoyable pick of the week: the Longform podcast (a podcast that features longform writers and their personal stories) featured TWIV favorite, science writer Carl Zimmer. Episode 223, 12/07/16.

Perhaps they would feature our beloved TWIV host in the future. Always nice when non-science based media focus on science.

Thank you sirs and madames,


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