During January 1-October 8, 2021, samples were collected from 1,600 blood donors; we tested 1,473 samples with complete epidemiologic data. Of those, 188 (12.7%) samples were positive for C. burnetii antibodies. Phase II IgG >200 was detected in 187 participants; concomitant phase I IgG >200 was detected in 57 (30%) of those participants' samples. Only 1 sample was found with positive phase I IgG and negative phase II IgG (Table 1). What does this mean in simplified terms