Hi @PontiusPrimate , sorry for the delay in reply to your post - still trying to get my head round some of this stuff - I did notice this commentary:
https://www.bmj.com/content/373/bmj.n958/rr-1
for some vaccines it seems there is a “very high viral load” :
"Although, the modern viral vectors that are used in CoViD vaccines are silenced (replication-deficient), each dose of the vaccine contains a very high viral load (e.g., 50 billion viral particles per dose in Ox/AZ or J&J/Janssen CoViD-19 vaccines whereas 100 billion viral particles per dose in the Sputnik-V). The viral particles are unlikely to be confined to the muscles at the injection site; they are free to distribute across the body and drain through the lymphatic system; their apparent volume of distribution is likely to be very high. The biodistribution of ChaAdOx1 containing HBV in BALB/c mice (study 0841MV38.001) indicated the highest viral levels at the injection site, but low levels of virus were still detected after 24 hours of injection in all other tissues (including blood, brain, heart, inguinal lymph node, kidney, liver, lung, gonads, and spleen). The proportional tissue distribution of viral vectors in the body tissues away from the injection site was likely to increase with time, however, biodistribution beyond 24h post-dose was not studied. "
The commentary goes on to be critical of the distribution studies of all the vaccines - on moderna e.g. :
“For COVID-19 mRNA Vaccine (Pfizer or Moderna), the biodistribution studies in animals were not conducted. The surrogate studies with luciferase and solid-lipid nanoparticles (Pfizer) confirm a biodistribution to the liver and other body tissues beyond the administration site [5]. For Moderna, the biodistribution of mRNA-1647 (encoding CMV genes) formulated in a similar lipid nanoparticulate delivery system confirms a biodistribution beyond the injection site, in particular, the distribution to the lymph nodes, spleen and the eye was noted [6]. However, the detailed tissue-specific distribution of mRNA vaccines encoding SARS-CoV-2 spike proteins (Pfizer or Moderna) is not fully known that can offer invaluable insights into the potential safety of these vaccines in peoples with pre-existing conditions or those on certain medications.”
I read this as saying the data is not in as to the levels of concentration at any one site - the proportions are stated in broad terms “highest concentrations” but with such a high volume of viral particles what is needed is “the detailed tissue-specific distribution of mRNA vaccines encoding SARS-CoV-2 spike proteins (Pfizer or Moderna)”.
out of 100 bn there could be 90 billion at the injection site but this still leaves 10 billion going elsewhere per injection!
cheers