1) Does this mean the case is not detectable or it was not detected? I.e. if another test was done the day after, is there a fair possibility of it picking up the infection, or is it forever ‘undetectable’ per the percentages noted in the article above and as referenced by yourself?
It means the test is flawed and antibody is not detected. People don’t have antibody the day after a new infection, so no test would pick it up.
Is it a certain ‘strain’ that is undetectable? I.e. if HSV1 was not detected in one person, would it be detectable in someone else assuming it transmitted between the two individuals?
We don’t know that – we only know grouped information
2) What are some stats/data on patients never developing antibodies or never testing positive on IGG for HSV1 and 2?
It depends on the test. The IgG misses 30% of HSV 1 and 8% of HSV 2, compared to the gold standard western blot
3) If one were to have a possible history of cold sores, would those antibodies protect from the
Very likely, yes, if the history of cold sores is correct.