Brea writes:

Hello TWIV and thank you for all you do!

Flagstaff, AZ – partly cloudy and 60°F 

Question for the covid clinical updates:

If you are fully vaccinated and exposed to covid, does it give your immune system a “boost” because it’s reacting to the virus? Same question but if you were to have a breakthrough infection? I am of course not saying that one should intentionally expose themselves, but am wondering if the vaccine provides protection from severe illness but community spread is still increasing, would a happenstance exposure potentially help boost ‘immunity’ for a little bit? 

Sorry if the question is not clear. Thank you for your time!

Best of Wishes,


Judy writes:

Hi, TWIVvers!

This one’s for Brianne. She and I have shared an interest in the germinal center story of SARS-CoV-2 infection, and I thought she’d appreciate this paper. 

As you know, there was a paper that came out back in August of 2020 by Kaneko et al. that showed that people infected with SARS-CoV-2 did not develop germinal centers. I think it was covered on TWIV at the time).

Well, it is now almost exactly one year later, and another paper has just come out showing that persistent germinal centers DO form in people vaccinated with the Pfizer BNT162b2 COVID-19 vaccine. Here is the link:

Just more evidence that immunity from vaccination is not the same, and indeed, is probably even better than immunity from natural infection.

I love the show, and I’m so appreciative of all the things you do for our community!

Stay well, and keep Racanielling!


Dan writes:

Greetings TWIV team and hello from Des Moines. High today of 33c, tropically humid and still a bit smokey here. Not great weather for hanging from a rope cleaning windows but someone has to do it, I suppose.

We’re about to have a giant state fair here and after the not so great study on COVID in deer, I’m wondering about the potential for zoonotic spread. Just to set the scene, the Iowa state fair normally gets over a million visitors. Very few people here are wearing masks. Daily cases are trending up, going from 50 or so per day a month ago to over 1500 yesterday. Population here is around 3.3 million, with around 50% fully vaccinated. 

At the state fair, there are large display barns filled with sheep, goats, cows, pigs and chickens, as well as other random animals. For example, they have a really big elk.The barns generally have pretty good air circulation-large doors that are kept open, big fans etc, but they are covered and will be filled with people. What’s the word on transmission to and from farm animals? To me, a guy that cleans windows, it seems like this might present a dangerous opportunity for a zoonotic crossover event. What does TWIV think?



Charles writes:

Hello TWiVers;

Another summer’s day in North Carolina. 93F (34C) a bit humid and some clouds. It may rain later today.

This may bug me more than it should, but I am sick and tired of articles and papers condemning antigen tests for SARS-CoV-2 because the authors are following the FDA’s lead and using the wrong “Gold Standard”. PCR should not be the gold standard, viral culture should be (see link 1 from NIH).

The latest example is from Germany and titled: “Diagnostic Efficacy of Rapid Antigen Testing for SARS-CoV-2: The COVid-19 AntiGen (COVAG) study” (link 2). I found it at MedPageToday with the headline: “Roche, Abbott COVID Antigen Tests Just So-So in Real-World Data — “Unsatisfactory” for screening asymptomatic people, say German lab professionals” (link 3).

What the hell do you want a screening test of asymptomatic people to do?  I would think you would want it to show if the person is infectious or not. Which test is better for that?  Well in most circumstances it is the antigen test. If you are tested very soon after exposure the PCR test would be better, but only for a day at the most. If you are asymptomatic and non-infectious, would you want a test to show you are infected?  Not me.

Sorry for the rant. I have been an advocate for antigen testing for a long time. Going back to before TWiV 640 with Michael Mina in July of 2020 with a letter to TWiV in early June of 2020. It upsets me that an uneducated IT guy gets it and those doing the research don’t. OK, it really pisses me off. I can’t imagine how you guys feel when you see so much bad research.

Thanks for letting me rant,

Charles Fischer




Debby writes:

TWIV has become a necessary part of my podcast diet–I love eavesdropping on this very cool journal club. You have exploded my understanding of viruses and biology in general. I look forward to every episode and I thank you all for your time, effort, wisdom, humility, and good humour. 

Listener pick:

This site allows you to follow the journey of a drop of water from any location in the contiguous United States to the ocean, using prodigious data sets from the US Geological Survey. You can adjust the speed and detail of your journey and you can pause anywhere along the way. Unfortunately, water that flows north through Canada stops at the border–I hope someone takes up the challenge to do this for the whole North American continent. 

(Rabbit hole warning) Enjoy!



Winnipeg MB

Lin writes:

Good morning Dr. Racaniello

(very early 12:30 am!)

Clouds in a dark sky here in western MA and damp from a day of drizzle. Temp 61 F, 16 C. 

Just listened to the morning medical report from Kansas with you as guest. You were nothing less than terrific! And the program is worthy of a daily watch. 

It was just a bit disheartening to see  Kansas not doing well with vaccination despite this amazing show with these articulate doctors answering excellent questions. 

This should give you many more twiv listeners and that is cheering. 

I have a listener pick: an excellent article from The Atlantic’s Kathryn Wu who rivals Ed Yong in her science writings. Her thesis: Waning antibodies doesn’t mean waning immunity. Memory B and T cells are going to kick in to fight off the virus and prevent severe disease and death.  It seems likely that for the majority of the vaccinated population who are not immunocompromised or very elderly, boosters should not be needed.

Best regards

just a retired molecular biologist