Karim writes:

Hello Dr. Racaniello,

As a pandemic inspired listener, I wanted to thank you and your team for the thoughtful and interesting discussions. TWIV has become my favorite podcast surpassing Marc Maron’s WTF podcast.

As you may know, Peloton has evolved into educational and inspirational workout sessions.  As an example, there’s a spin bike instructor who gets people moving while telling an entertaining story about Oprah’s interview methods.  

I look forward to a future Peloton session with Dr. Condit summarizing a research paper while enthusiastically shouting out spin bike resistance levels.

All the best,


Christa writes:

Hey there TWIV team!

I’ve been listening since the beginning of covid, and am sincerely thankful for your insights. I’m a stay at home mom, with 4 kids ages 17-4, you guys really helped me make good decisions to keep my family safe. 

I began volunteering at the mass vaccination site where they can administer 2000 shots a day. Because I volunteer, I was able to get a leftover dose fairly early on. And now I’m fully vaccinated! 

I also donate blood regularly to the Red Cross. It was interesting to see the way that they gave antibody test results once I was fully vaccinated. This whole time, I would come back “Negative”, however after my last donation I came back as “Reactive”. For a second I worried that I had contracted COVID, but upon reading the results I see that this is a new step that the Red Cross has added to verify that a person has been vaccinated, the vaccine is working, and they remain negative for covid antibodies. 

So cool! I donate again in May, and find these little bits of feedback fascinating. If my vaccine wears off I would actually be able to catch it, right?

Below I will link the screenshots of the Red Cross results, so that you can see the way it’s presented. 

I do have one question, and it’s probably dumb and not related to the Red Cross thing at all: 

Q: At what point in a viruses evolution does it become a new disease? We have sars 1, Mers, common coronavirus colds, and sars-cov-2. Can they evolve to a point where it’s considered a new virus, or is evolution of one identified virus always a variant of that virus? (I’m sure my terminology isn’t perfect, I mostly talk to kids and chickens)

Anyways, thanks for what you do. Stay Cool


“What does my result mean?


“REACTIVITY”, since that result (for the listener and me) states

Reactive test result: Indicates that your initial antibody test was reactive for COVID-19 antibodies. The Red Cross uses two antibody tests to generate our results. While it is uncommon, some donations may not complete both tests due to processing issues. The initial test detects antibodies to the spike protein of the virus, that are produced in response to viral infection or the vaccine. The other detects antibodies to a different part of the virus called the nucleocapsid protein, which are produced in response to infection, but not by the current vaccines. If a donor has had the COVID-19 vaccine, they will generate antibodies against the spike protein but not the nucleocapsid protein, which will only occur in the event of a COVID-19 infection. A reactive result on the antibody test usually requires about one to three weeks from the receipt of the first dose of a vaccine.

Spencer writes:

I am a front line internist diagnosing and caring for patients with Covid19.  I am also a graduate of Cornell U and Mt. Sinai/CUNY graduate school. My question deals with the replication competency of the COVID-19 virus. The CDC instructions are that an infected patient can end quarantine after 10 days because the virus is less capable of replicating although still could be found in nasal swabs from the patient by PCR amplification.  Is it because the host is not likely to replicate the virus and the immune response decreases the infectivity?  Why is this?  I understood that viral replication assays show decreased replication after 10 days. Why does the virus lose its ability to replicate in a new host?  Are there any markers that might be used clinically, besides a viral replication assay, to see if the virus has been cleared or have reduced transmissibility in the host and importantly also not likely to be replication competent in a new host?  

Thanks.  I’ve been listening to TWIV and TWIP since the very beginning.

Spencer Kroll MD PhD

Tracey writes:

Hi Vincent and TWiV Team,

I have written to you guys a couple of times already, but to no avail. I appreciate that you must get a tonne of mail, so no hard feelings, but thought I’d keep trying.

So, I am writing to you once again from Nouméa in New Caledonia, where we have had a crazy few days. A tsunami warning on Friday, followed by the category five tropical cyclone Niran on Saturday, and the clean-up operation on Sunday marred by the announcement that SARS-CoV-2 has now broken into the community here. It had been contained since we first had a successful four-week lockdown last March which was followed up with a very strict government-controlled quarantine. Obviously, something did not work and we are now back in lockdown from midnight tonight, 9 March.

There are rumours aplenty bouncing around about patient zero, but these are not helpful. What we need is for the French government to up the vaccination program here (only 5210 people have received at least one jab to date) and for all of us who have hitherto enjoyed a pretty normal life to get with the global program and change our behaviour, which is certainly not pandemically-prepared (is that a phrase?) Ditch the bisous, stick a mask on your face and keep your distance. Seems obvious to those who have been doing this for a year already, but we are woefully behind here. I wish that TWiV were also available in French so I could share your advice more easily, but I guess there isn’t a French equivalent?

As vaccine hesitancy here looks likely to be a problem, is there any advice you can give me on how to convince those who are a bit hesitant to get involved (once we have a better supply of course)? I know you have posted a lot of useful links, but if you know of anything in French, then that would be one less hurdle for people.

Thank you all so much for all that you do, it truly is wonderful. I arrived at TWiV last year through Immune when I was searching for good info on vaccine development. Your podcasts are so addictive and motivate me when I am cleaning the house! I am with you for the long run (I hope, as I am only in my forties…)


(Welsh person living in New Caledonia)