Selection and characteristics of samples used in this study. (A) Study flow diagram. (B) Comparison of clinical characteristics between the three types of samples, positive (+), idiopathic, and negative (−) chosen for this study. Ag, antigen; Ser, serology; Spn, Streptococcus pneumoniae; Nmen, Neisseria meningitidis; Hib, Haemophilus influenzae type b; GBS, group B Streptococcus; CHIKV, Chikungunya virus; PMNs, polymorphonuclear neutrophils; +ve, positive; -ve, negative; LAMA, left against medical advice.