I don't think "still" and "up to" quite work together. I suggest: The child, at the time of writing, is still very sick.
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HifaMoWhat about 'until the time of writing'?Thank you.That does not work very well either. "until" has a nuance of change, while "still" has a nuance of no change.
HifaMoThe child, up to this moment of writing, is still very sick.I don't see anything inherently worse in the original version beyond the number of words. This could be solved much more decidedly by simply deleting the unnecessary phrase—with no loss of information: