Hello. I'm a newbie as well, but I hope you can find some use out of this feedback.
You've stated outright that the basis for -B is yourself, which is fine because it really is easier to write what you know, and it's a good trick for making your human more realistic. I think that's fine.
But Roget has a point- the article does lean towards focus on -B rather than on -1990. Not because of how much of the article you dedicate to the host per say, but because the parts that are -B-centric are detailed in a particular way. (Sorry, "a particular way" is a vague phrase, but my English is not good enough… I cannot find an English word to explain what I mean.)
I think the part that reads, "The subject has requested to use the standard issue female outfit, request is currently pending a psychological evaluation" is unnecessary, because even though it adds depth (character) to the host and makes the reader Insert Possible Explanations Here, it seems pointless. There is no follow-up, and even if there were, it seems as though it could not have relevance to the real point of your article, the -1990 virus.
To focus your article back to the virus, I suggest expanding on "Undeveloped specimens of SCP-1990-A can be treated with a regiment of Niclosamide, once the specimen develops it is completely connected to the host's nervous system (this is indicated by the 'bloom' seen emerging from a hosts tear duct.)"
What happens after the "bloom"? How long/what circumstances before the "bomb" is triggered? Here you've said that "a nice sunny day is all it takes to detonate you," so sunlight is a trigger? If so, shouldn't it be noted (even if it is unnecessary) in the containment procedures that -B cannot be exposed to sunlight? Not only that, but what about when -B eventually dies? Providing theories about what will happen to -1990 once it loses its host would be nice.
Also, I think it would help if your description began with -1990 instead of -B. -1990 is, after all, the actual SCP and should be acknowledged first.
Um, what else…
If I were in your shoes, I would write the entire thing as though the host was not specified to be human, and then emphasize the important traits/procedures relevant to the virus only. Then, I would say to myself, "Now what if the host were human?" and add in the accommodations I would expect the SCP Foundation to make for this human.
I think this is a good idea. I like it, and I think it fits in with the vibe of existing SCP items because it's one of those things where the scary part isn't completely inherent, but potential- "If this virus were to escape, world population would plummet and people would explode everywhere. Luckily, it's contained, so wipe that sweat off your brow. Yay. But just saying, this could kill everybody."