(A)When virus enters the cell (naso oropharyngeal), different scenarios can result.
1. One, it is taken up and is killed by the macrophages. No antibodies are formed, the patient is asymptomatic.
2. In some persons, the virus enters the blood → dendritic cells in thymus →T cells and then to B cells and produces IgG and IgM. The patient is asymptomatic, but antibodies are formed.
3. In a third scenario, the cells produce IFN-1 on Day 1, which initiates neutrophils, NK cells and monocytes. The NK cells and monocytes produce IFN-γ, which kills the virus as do the neutrophils. The patient remains asymptomatic because of adequate immunity.
4. Another scenario, the IFN-γ will produce TNF-α, which causes inflammation. The person will be symptomatic on Day 1 (fever, diarrhea, headache, rash, loss of smell/taste).
5. If the immunity is inadequate, the virus is not killed. The cells do not form IFN-1 in such a situation, alternate pathway opens up on Day 3. Macrophages produce NLRP3, which produces IL-1β and IL-18. IL-1β increases ferritin levels, glucuronidase causing tissue damage. IL-18 adds to the inflammation. Cells through the cellular dendritic cells produce Th1 cells, which produce IL-6 (formed on Day 3), TNF-α and IL-8. IL-6 causes clot formation, TNF-α (formed on Day 1), IL-8 and IL-1β (formed on Day 3), cause inflammation.
Clot formation will be seen as rising d-dimer and fibrinogen, inflammation present as high CRP, tissue damage as raised LDH and ESR.
(B) Drugs act at different levels: mefenamic acid (NLRP3, PLA2 and ILs), steroids (PLA2), tocilizumab (IL-6), infliximab (TNF-a), methylene blue (bradykinin).
(C) The four vaccines (masking, physical distancing, hand hygiene and povidone iodine oral wash) are much more important than the fifth actual vaccine.
The vaccine may not protect from inflammation occurring anywhere in the body.
The virus does not kill the person directly; it is the hyperinflammation caused by the cytokine storm and the immunity of the person reacting to the viral invasion that kills the person or causes the morbidity.
(D) Aerosol generating behaviors are shouting, speaking loudly; aerosol generating sounds are those where diaphragm movement is involved.