Monika writes:

Hi all, thank you so much for all your good work and clear explanations. I have a Master of Science degree, but in a field far away from viruses, pandemics, medicine and vaccinations. But when the pandemic hit, my way of coping with the anxiety and stress levels was to get good quality information. That’s how I found you (and others), and it really helped me a lot. So thanks for that. In the summer of 2020 I had the chance to be part of a phase 3 trial for a vaccine. And I eagerly wanted to be part of the solution. I knew then a lot about this specific vaccine, had the chance to talk to doctors within the trial and also some who volunteered for the trial themselves. And I also thought that I knew a lot about double blinded random controlled trials. But later on I realised that I missed a couple of points: I thought that the efficacy will be shown by counting our antibodies 3 weeks after the second dose, and after that it would be unblinded. Then we got the info, no we want to test it in real life, so the trial stays blind until a certain number get infected. OK, that’s understandable. But now 10 months after the first dose it is still blind. Where the rest of my friends and family have gotten real vaccines, officially I still don’t know what I got and if I am protected. I also have no official proof of being vaccinated, which makes life now difficult. So what I did last week is to quit the trial, and got my first Pfizer. And at the end of June I will get my second shot which allows me to visit my home country and family for the first time in 2 years.

My question for you would be: if trials are always blind for a whole year and if you think that this should be the same during a pandemic? I am not sure if it is ethically fine, that people who volunteered and only got the placebo, are living for a whole year without any protection.

By the way I managed to find out (not officially) that I received the real shots last summer, so I will now soon be 4 times vaccinated.

Thanks a lot. Keep up the good work.


(MSc in Math and Geometry, trial volunteer for Sinopharm – inactivated virus) 

Bob writes:

Looking at booster shots from another perspecTWiVe …

If I am just over two weeks past my second Pfizer mRNA shot, I expect that my antibody count will be at a local high, and that my T-cells will be at the ready to defend me to the best of their ability.

Should I actively seek close un-masked contact with a person who is in their SARS-CoV-2 contagious stage, that has been infected with a “vaccine escape” enabled variant?  I’m thinking that the resulting boost that I receive will gain me improved protection against future variants.


Just a mechanical engineer

on Vancouver Island, in British Columbia, Canada

Lori writes:

Good afternoon.

I listen to the TWIV podcast periodically and have a COVID-related question that I thought would be best posed to your team.

Now that I am fully vaccinated, is it safe to return to in-person worship at my church WITHOUT a mask and WITHOUT social distancing?

It seems that everyone has jumped on this bandwagon but I wasn’t sure if this was safe and I still have some reservations.

But, I am also eager to attend church in person once again.

Any insights that you can provide would be most appreciated.

Thank you ~


Sebastian writes:

Hi TWiV,

Hello from Belgium, where the weather is an untypical but extremely pleasant 23°C and sunny. 

I became a regular listener of TWiV ever since COVID made me want to brush up on my virology, but recently I find myself liking the non-COVID episodes more and more. 

I just finished episode 756, on the development of new polio vaccines and their test in the 68-containers “Poliopolis”. I had the chance to listen to Hilde Revets at the 2018 meeting of the Belgian Society of Microbiology and remembered a neat detail you didn’t mention: Belgium switched from OPV to IPV only in 2000 and has very high polio vaccine uptake, meaning at the time of the trial, almost the entire adult population had some level of gut immunity. This is great for limiting the risk of circulating virus if some managed to escape Poliopolis. That same factor however made Belgians unsuitable test subjects for the trial. Luckily, a large number of Dutch studies and work in Antwerpen, and the Netherlands switched from OPV to IPV before we did in Belgium. By recruiting Dutch students in Belgium, they had both the benefit of running the trial in a community that has great level of immunity including gut immunity, and of having volunteers that had been vaccinated with IPV. The volunteers however had to agree to remain in Belgium for a certain time after the experiment because levels of vaccination in the so-called Dutch Bible Belt are quite low. 

Cheers and please never stop your great work, especially the non-COVID episodes,


P.S. A few episodes back, you made a list of favorites among the older episodes. Would it be possible to have to list pinned somewhere on the website? Maybe I missed it, but it would be a great resource for new listeners. 


Sebastian Worms

Biochemistry and Genetics of Microorganisms – BGM 

Louvain Institute of Biomolecular Science and Technology – LIBST

Jennifer writes:

Dearest TWIV Team,

Thank you so very much for the fascinating conversations you freely post for us to listen to!

I have learned an incredible amount from you all. Here is my question from a close friend…

As you may be aware, Canada has had a different approach to SARS-CoV-2 vaccinations than the USA (entirely due to vaccine scarcity).  This has put some people in interesting scenarios, one of which I would like to ask about…

A 65-year-old took the first available vaccine (AstraZeneca) for their first dose (Dr. Daniel Griffin would be happy LOL!).

Canada approved mixing of manufacturers between first and second doses.

Pfizer has increased shipments to Canada and is the predominant vaccine currently available (early June 2021).

Note: This person has a grandchild undergoing cancer treatment, so would like to make the best decision for the lowest possible breakthough infection and/or transmission.

Question: Should this person take the first available second dose regardless of manufacturer? Is there a possible advantage in getting the slightly more effective Pfizer vaccine for their second dose?  

I find it hard to find the answer to this in the articles out there.  Any thoughts?

Many, many thanks,


(Specialist in dialysis and water treatment equipment management in lovely Victoria, BC)

Daniel said, just get the first available second dose.

Kevin writes:

Hello Vincent and TWIV team

This may sound like a strange question, but ‘how good are you guys’?

Let me explain why I ask.

My degree is in Physics, far away from what you guys talk about. But I have always tried to have a scientific/logical/objective/evidential outlook on life, and it seems to me that is what you do as well.

When discussing the pandemic with friends, I sometimes mention TWIV episodes, but sometimes get the reply ‘But who are those guys, it is only 4 people having a chat. Why should I believe them and not Dr/Prof (insert name)’?

Is there some international association of senior virologists that you are part of?

Is there another measure of credibility that I can point to when I mention you?

Anyway, keep up the good work. I enjoy listening and watching, even if I don’t understand what you are talking about half the time!!