This question is motivated by the fact that TLR 7 agonists have been linked to development and acceleration of Lupus-like disease both in animals and human beings. But at the same time, TLR 7 agonist at lower doses is also being used as vaccine adjuvant (in covid vaccine- Covaxin, for example).
I will quantify the what I know. The study on murine model shows that a dose of 100 microgram of TLR 7 agonist, 3 times a week, for 8 week, is lethal for mice and triggers Lupus-like disease. On the other hand, a single dose of covaxin has 15 microgram of TLR 7 agonist. That is, for two doses 4-8 weeks apart will give total 30 microgram dose to human beings.
Now human beings are about 3000 times heavier than mice. So, the lethal equivalent to human beings should be frequent doses of 300 milligram. What Covaxin gives is a total of 30 micrograms.
My question is, does this imply that Covaxin is safe for human beings? How do we interpret these numbers? Is there better understanding available in the field that can throw some light on what level of dosage of TLR 7 agonist is safe and when does it backfire?