Jenny writes:

Hello Dr Griffin,

I  got the J&J vaccine back in March. Recently I heard on the news that the J&J vaccine is less effective against the Delta variant than any two-dose vaccines. I’m wondering if I should consider getting a second dose (of Pfizer or Moderna) to increase my protection against the Delta variant (from ~60 to 80%)?

thank you

David writes:

Dear Dr. Griffin,

I am especially vulnerable to COVID as the result of age and a number of underlying conditions.  I was vaccinated in February (Moderna vaccine) and was beginning to feel freer in what I could do until I read a newspaper article reporting on a study finding that even low doses of prednisone could dramatically reduce antibody production from the vaccine.  I was taking 5 mg of prednisone at the time I was vaccinated for an autoimmune lung disease.  I took the antibody test and the result was that there were no detectable antibodies.

My doctor informs me that I probably still have some protection through other mechanisms, but there is no way of knowing if this is the case or how significant the other protections are.  The doctor prescribing the prednisone has told me that I could stop it temporarily to get revaccinated.  If I do this and then resume the prednisone, are the antibodies likely to be suppressed again? Is there any way of measuring what degree of protection I have absent measurable antibodies?  Do you have any advice for me?

Thanks for considering this question.


Mark writes:


I’m a clinician and past clinical researcher who’s been involved with chronic fatigue syndrome since the mid 1980s. 

I’ve seen and helped manage around 5 to 6 thousand people with CFS, all the way from near permanently bed-bound patients to impaired Olympic athletes, in both inpatient and outpatient settings. 

The story of many long Covid patients is, to me, indistinguishable from my post-EBV, post-dengue and post-Ross River viral cases here in Australia.  In many of these, specific viral IgM remains raised, and abnormalities of T lymphocytes keep supporting a hypothesis of persistent immune failure to bring the infection to an end. 

The few COVID-19 patients with persistent symptoms I have seen show the same immunology changes, although I know that this is a very small sample, and likely selection bias. We’ve had very few cases in Australia so far, but that will change with opening of our borders and our low vaccination rates. 

My question is, could long Covid be a specific instance of chronic fatigue syndrome? No diagnostic tests, a wide range of symptoms and disability, no clear mechanism identified, a lack of disease classification impairing care?

You raised dysautonomia as one component, and this is especially common in young people with CFS. Treatment for postural orthostatic tachycardia syndrome (POTS) is well established and does provide considerable reduction of disability for many while we await deeper understanding of these conditions. 

Cheers from Australia
Dr Mark Donohoe