Is it appropriate to use NHOID in this example where you are testing anti-RSV epitope IgG antibody in the patient? The bug is the subject of the observation, this is measuring host/subject immune response.
This example is been tweaked to include NHOID, see the orginal IS example 5 in the SDTMIG 3.4: IS Example 5
In the published examples where NHOID is used, observations are made and tests are run on the bug - the result tells you something about the bug:
is it susceptible to an antibiotics (MS)
does it have some mutations in its genome (GF)
can the antibody stop it from infecting cells (IS)
all of the above, you are running tests that directly impact the microbe, and tells you something about the microbe.
In the below example, this is measuring the subject/host immune response toward a vaccine-delivered antigen, the observation is about the study subject, not about the bug. Having NHOID here is beyond the scope of how this variable is defined and used.
If you want to know which strain of the virus is used to make and generate the vaccine, is that actually device domain information?