Dora writes:


I live in Austin, Texas.  But even when I was growing up in upstate New  York, my father used to tell me that the great threat to orange growing  in Florida is not freezing weather, it is warm weather that comes before  they’re done with freezing weather.  The citrus trees bloom and then the  blooms freeze.

In Austin I can readily see what the problem is.   When I moved here in  2000, there was a reliable pattern.  The temperatures used to last rise  to the mid 80s in early November, and first rise to the mid 80s on  Valentines Day.  On Valentines Day you go down the street and suddenly  there are leaves and/or flowers on the trees, with the ash trees it’s  flowers, and on the ground flowers are blooming.   But in late winter/  early spring in central Texas, the weather is very volatile.  Very warm  weather and frosts alternate on a weekly basis for the next three or  four weeks until last frost in mid March.   Since I have been here, the  date of last frost has subtly gotten later as the weather gets less  stable. If a killing frost, where the temperature falls into the 20s and  stays there for a few hours, happens after leaves and flowers appear on  the trees, they die, and they don’t reappear until April, leading to a  depressing early spring. That used to happen more times than not.

Last winter it stayed so warm that flowers never stopped blooming.  Then  suddenly on Valentines Day the polar vortex, which Texas rarely sees,  came spinning south, and got cut off and sat there for a week.  Temperatures, that never get below 19 in Austin, plummeted to 5 degrees, while storms that normally hit Washington and Oregon went around the big polar vortex and came right over Austin, every other day.  Our infrastructure isn’t designed for this, and many people had no heat for the entire week, and everyone else saw it keep going on and off. All over the city water mains broke.  The trees had broken out in leaves and flowers a week or two early, and every single tree branch in the city that had leaves or flowers on it DIED, leading to dead trees and trees with half their branches dead, usually on the outside of the tree.  Many bushes and trees died or died back to ground level.  The polar vortex of course is breaking down because the arctic is warming and can be expected to spin south regularly.  In fact this has been happening for years, it just doesn’t usually head for Texas.

This year it stayed warm so late that the last leaves just fell off the trees this weekend, that normally happens by Christmas Day, when everyone goes out and rakes up their leaves.



Gratiela writes:

Dear TWIV,

I thank my lucky stars that you exist and always tune in with pleasure. I am an unconditional fan.

Unfortunately, I can’t say the same about doctors these days, and that is a strange feeling.

Just generally, how are we, the wider public, to understand some doctors’ reactions in the UK and elsewhere in saying that they themselves should not have the vaccine? I am less angry than puzzled (I am fully vaccinated, booster included). Such people say that they are grateful for the vaccine, yet they themselves will not take it. In the UK, but only in England, about 10% of medical staff will be affected by the government decision to make vaccination compulsory for medical staff.

I am not aware that you would have referred to this, but if you have, I would be grateful if you pointed me to the podcast in which you discussed this. I would equally be grateful if you could discuss this from the point of view of how we are to understand and relate to science if messages become so nuanced, as they seem to have become. I always thought that, even though they are researchers, doctors working in a clinical environment know more about science than I do, being, as I am, educated in sociology and humanities.

Thank you for your efforts. Twiv is beautiful.

Kind regards,


Shawn writes:

Hello TWIVsters,

I have only started listening recently so apologies if this has been asked before.

Is there a difference between e.g 4 fold and 4 times. I hear things like ‘there was a 4 fold increase in something’. I always thought a 4 fold increase meant 2^4, so 16 times. I understood ‘fold’ to be an analogy to folding a piece of paper over and over again and the exponential increase in the resulting number of layers of paper. These terms are used interchangeably on the podcast.

I started listening during the pandemic and I think you all provide an incredible service. I have started Vincent’s virology course on Youtube and I’m fascinated. My education in biology ended mid-high school so I spend a lot of time with the lecture paused and googling for background.

Love the show



Adam writes:

Dear TWIV team

Such a privilege to listen to #858 with John Mascola and to get a glimpse into the selfless world of public health that protects us all.

The discussion touched on evolutionary pressures leading to Phase 1 candidates, biologic and immunologic surveillance and the need to build sustainable structures that that can be called into use.

Around 54:50 Rich raised the subject of surge capacity (I paraphrase): You want to be ready with science, tech and manufacturing, but you can’t build this capacity and just let it sit there for 20 years … You have to be able to shift the capacity to accommodate the surge that comes with a pandemic. It seems like a huge problem.

John Mascola: It’s feasible if people are thoughtful and intelligent … One can build critical research capacity in various regions of the world where they can be doing immunologic surveillance.

Alan: Models from other spheres of activity suggest a way to do this. For example volunteer fire departments where volunteers are trained and then get called up as needed.

John Mascola then referred to ‘regional capacity’: it should be possible to have manufacturing based regionally – which led to Brianne’s comment about developing a platform which can then ‘pivot’ to deal with whatever pandemic comes along.

It struck me that this description of the public health system implies an organization with counterparts in the intra-corporeal immune system: humoral and surface antibodies, memory cells and germinal centres and (just like research) pre-infection modulation of immunity.

I wonder if the presence of a pattern might offer a little information. Perhaps public health officials developing a structure for research been following the same evolutionary pressures that have brought about the mechanisms for immunity – this is not a testable scientific argument, of course, but there may be clues of use in pandemic planning.

All the best from London (where, as a correspondent said last week, we expect the weather you had on the east coast 2 weeks ago: I’m guessing in line with #855)


Ken writes:

54° F / 12° C and sunny in Glendale, AZ at the time of this email 🙂

I am fairly new to the YouTube channel, but the series of podcasts has quickly become one of my favorites. I apologize if the following feature exists; I have not been able to find it either on YouTube or the website. The premise of most of these shows involves discussing and dissecting various papers. As a listener, it is interesting to hear subject matter experts confer on various aspects of the paper. I want to be more than a passive listener with these podcasts. I was wondering if there could be an email group established that would connect with the audience and “assign” the papers that will be discussed before the show. I understand sending the actual pdf may be problematic, but at least the information sent and those with access to databases could acquire the paper individually. I would use that opportunity to look at the paper, write notes in the margins (as we all do), and compare my notes with those of the experts. I’m sure there are many other benefits to this approach, but this may be another step in your vision for the program to educate people on virology (and science) and indirectly teaches/reinforces the approach by reading journal articles. I’ll stop the message there because I want to respect your time. Thanks for all you do. You and your colleagues are having a positive effect on the world.


Dusty writes:

Hey TWiV team, thanks for all your hard work with science communication. While I know I will never have time to listen to all of the back episodes I’m glad to know that you all have probably covered any aspect in virology I may be interested in if I ever want to learn more about a topic. It has been so helpful to me to hear other scientists work through an area I have very little experience in but a newfound interest in over the last two years.

While I was listening to episode 860 you all were talking about science funding and the differences between academia and the NIH and others and I was reminded of another podcast I had heard recently discussing about how NASA is working to address the biases in which projects are funded 

or given telescope time. With the exciting launch of the James Webb Telescope hopefully some other disciplines will be inspired to improve the ways they fund projects.