Jamie writes:

I’m 9 weeks pregnant and at my first OB visit, I asked when I should get my Covid booster.

My provider said that they were not recommending boosters in general. She didn’t give specifics as to why not, just that there was no confidence that we need them.

I have had 3 Pfizer vaccine shots, and I had Covid November 2022. I’m a generally healthy, 42 year old woman.

What do you recommend?

Thank you!

Sol writes:

Dr Griffin, when you talk about death rates in children, are there any data on underlying conditions for this group, immunocompromised, diabetes, etc.? Do we know what percentage are previously healthy children. Thank you


Dra. Sol Burokas

Sección Infectología 

Comité de Control de Infecciones

Hospital Italiano de Buenos Aires

Alan writes:

Dear Daniel,

There’s a young physicist, Dianna Cowan, who has become well-known and well-loved for her educational physics videos over the last several years. I am among the 2.6 million subscribers to her channel; my interest in science spreads a wide net, and her enthusiasm alone would be enough to keep me engaged.

She has long Covid, and her condition has lately deteriorated to the point where a friend made this video as a way to help keep her wider circle of friends informed. It is hard to watch. I lack the professional knowledge or detachment to be unaffected.

The situation is obviously a difficult and emotional one for her husband and family, but I’m writing this because, despite carefully following TWiV, taking Vincent’s course online (twice), and keeping up with the clinical updates, I had not been aware that ME/CFS could become life-threatening for a relatively young, energetic, and active individual like “Physics Girl.”

If you have any guidance to offer, or even some insight into how this comes about, I would appreciate it and be happy to pass it along.

All the very best, and thank you for what you do.


Zain writes:

Hi Daniel,

Just wanted to bring up this study which is our Ontario experience on off-label dosing of paxlovid for chronic kidney disease (dialysis).  Reduced dose paxlovid was very effective here, and in fact has been our standard for CKD patients requiring therapy.  Remdesivir is really hard to come by locally (outside of transplant), and molnupiravir was not approved in Canada, so this seems to be a really nice way of getting paxlovid to those high risk CKD patients.

Early Experience with Modified Dose Nirmatrelvir/Ritonavir in Dialysis Patients with Coronavirus Disease 2019 https://journals.lww.com/cjasn/Abstract/9900/Early_Experience_with_Modified_Dose.71.aspx

Zain Chagla, MSc MD DTMH FRCPC

Associate Professor

Co-Medical Director Infection Control and Head of Infectious Diseases Service, St. Joseph’s Healthcare Hamilton

Donald writes:

Dear Daniel and Vincent,

I didn’t say anything the first Daniel mentioned norovirus and alcohol based hand sanitizers, but since he’s mentioned it twice now (TWIV 986 and 988) I feel the need to correct some misperception on alcohol-based hand sanitizers and norovirus.

While it is true, that conventionally formulated alcohol-based hand sanitizers have limited effectiveness against non-enveloped viruses, including norovirus, (https://doi.org/10.4315/0362-028X.JFP-12-532) there is research in the published literature, which indicates that these products can be reformulated to have significantly greater efficacy. See the citations below, for example.



These products are available for sale, and are used in some restaurant chains (Chipotle) for example, as well as by some cruise lines.

And while handwashing is always a good idea, it is certainly not magic. Published data indicates that handwashing removes 99% of microorganisms on hands (2 log reduction), while feces may contain 9 log (10^9) virus particles per gram. https://wwwnc.cdc.gov/eid/article/14/10/08-0117_article.

– Don


Donald W. Schaffner, Ph.D.

Distinguished Professor and Extension Specialist

Rutgers, The State University of New Jersey