Mark writes:

Love your podcast. I’m not in the business, just a curious “civilian” who appreciates the breadth and depth you bring to various topics. 

I don’t know if you take listener questions, but if you haven’t already, I’d be curious to learn about “immune fatigue” as it relates to multiple C19 vaccinations. 

I’ve vaccinated & boosted (J&J, the Pfizer). I see Pfizer is already putting the wheels in motion for authorization of a 2nd booster (and have followed Israel’s policy of doing exactly that for folks that are older or have comorbidities). 

Even as the CDC still noodles over it, the San Francisco Department of Public Health has authorized and recommended a 2nd booster for anyone, regardless of age or comorbidities, who began their immunizations with J&J. No reasoning shared yet. 2nd mRNA booster to be 5 months after the 1st. 

I’m 56 and in that boat. I’m doing a full month of work travel beginning mid-April, and I think I’m going to get that 2nd booster this weekend. 

My only concern has been the light chatter about possible immune fatigue from getting so many jabs. Is that genuinely a thing, or just a postulate? 

Cheers & keep up the good work! 


Mario writes:

Dear TWIV Team,

In episode #879 you discuss a Nature paper on altered TMPRSS2 utilisation by the Omicron variant of SARS-COV2. Given the apparent importance of the presence of a furin cleavage site which enables TMPRSS2 cleavage of spike in the pandemic spread of the coronavirus, it is surprising that this biological characteristic is now lost in the Omicron variant. Possible reasons for apparent selection of this change in Omicron are not given in the Nature paper and were not discussed in the TWIV episode. 

My ‘blind virologist’ guess is that ablation or reduction of cell surface fusion in Omicron infection as a consequence of loss of the furin cleavage site may further contribute to immune escape of the variant. While entry of enveloped viruses by fusion at the cell surface will result in the presence of viral membrane/antigens on the surface of infected cells, this is not the case when viruses enter via the endosomal/lysosomal pathway. Notably, in the former case infected cells could be targets for antibody-dependent cytotoxicity, whereby virus propagation could be reduced in a host that has humoral immunity to the virus.

With best wishes, Mario

Brenda writes:



Flavia writes:

My husband and I have thoroughly enjoyed, learned from, and appreciated many TWIV episodes — even when we struggle to understand terminology “weeds” used in TWIV discussions.

A Vaccine Pathway for Herpes Virus with Gregory Smith, PhD

I just saw on YouTube the following report and am wondering if — hoping that — you all might discuss this published report (in Nature) on a future TWIV episode.

Gregory Smith, PhD, professor of Microbiology-Immunology at Feinberg, has been investigating a path to long-needed vaccine development for herpes virus. He recently published findings in the journal Nature that bring the possibility of a preventive vaccine a step closer.

On another note, we recently attended a “Cafe Scientifique” presentation on viruses given by Dr. David Beckham of the University of Colorado School of Medicine. After his presentation, we asked him if he happened to be a TWIVver, to which he responded YES! and in fact had had lunch with you at the last (?) ASV annual meeting in Minnesota. We felt so “IN” knowing about TWIV!!

PS:  All our Amazon purchases are now made through AmazonSmile.  😊

Thank you all for your fascinating and important Microbe.TV science FACTS. 

Flavia, Denver CO

Nikolai writes:

Hello twivers,

I have been a fan since twiv #720, ever since I bought my first car. I’m a 1st year student at the University of Cambridge, studying biological natural sciences with plans of specializing in biochemistry, but this podcast has definitely sparked my interest in virology, which has been helpful in my essays. 

This past month, TWiV has been a major grounding point for me as I’ve been catching up on older episodes while driving supplies to Ukraine. As a Ukrainian, I felt like I’ve had to do anything I can to help and, though I’ve put my studies on pause, I wanted to keep learning even in this turbulent time. So thank you twiv for unknowingly being there for me! 

Now I have joined the Ukrainian resistance in a volunteer battalion as a medic. Our unit specifically is working on building and operating drones, which will be used to deliver humanitarian aid to places where humanitarian corridors have not been established yet, such as donor blood and vital medication among other cargo. As we are a volunteer unit we do not get any funding from the government and have to rely on our own finances, which is why I am currently doing a fundraiser, information about which is on my Facebook and Instagram pages which you can find by searching my name! 

Thank you for all the great work you’ve been doing for the scientific community! 

All the best,

Nikolai Nizalov 

PS I have downloaded some episodes to cheer me up,  for when I’m closer to the front lines!

Nikolai on Instagram and Facebook

Sue writes:

Hi TWIVers- love love your podcast! I just finished episode 869 and heard Rich’s pick and the interest in the Illusion Art Museum in Prague. If you don’t know about it, there is a similar and rather astonishing museum in Baltimore called the American Visionary Arts Museum. This Tesla piece would fit right in. I’ve seen things like this and pieces even more astounding. (One of the artists we discovered there is Dalton Getty who sculpts/carves intricate objects from pencil lead without magnification.) Their biggest fundraiser is the Kinetic Sculpture Race. slamming science into art in the best, most fun ways. I can’t explain it at all. 

They explain themselves: 

AVAM specializes in original thematic exhibitions that seamlessly combine art, science, philosophy, humor and especially social justice and betterment.

Go to Baltimore. And thanks for keeping me (somewhat) sane and educated for the last two years!   


from Pittsburgh where it’s a cloudless (!!!!) sunny and crisp 33° F (0.6°C.) 

Frazer writes:

Dear TWIVers,

I am a PhD student in virology at the University of Leeds, focussing on Hepatitis E virus. I found this article on the BBC that was incredibly interesting, since TWIV recently was discussing fieldwork and animal viruses;

Vaccine trial for killer elephant virus begins – BBC News

Scientists are embarking on the first trial of a vaccine to shield elephants from a deadly disease.

Keep up the great work! Best wishes from a cloudy 8 degrees C Leeds, recovering from a recent storm.