Fig. 6From: Serological evidence of human infections with highly pathogenic avian influenza A(H5N1) virus: a systematic review and meta-analysisComparison of seroconversion rate and seroincidence for human infection with highly pathogenic avian influenza A(H5N1) virus estimated through random effects models by type of exposure, using a non-standardized antibody titer threshold. The non-standardized antibody titer threshold refers to criteria to define seropositive results in each study rather than the World Health Organization-recommended or modified World Health Organization-recommended criteria [i.e., a neutralizing (NT) antibody titer ≥ 1:80 with a positive result confirmed by a 2nd assay (i.e., HAI antibody titer ≥ 1:40, ELISA or western blot assay)]. Data are presented for seroconversion rate for human infection with A(H5N1) virus (a), and seroincidence of human infection with A(H5N1) virus considering whether A(H5N1) outbreaks in humans or animal reservoirs occurred (b) or not (c). The red color in panel a represents the estimates of the pooled seroconversion rate are based on all thirteen studies excluding reports related to A(H5N1) outbreaks in Hong Kong in 1997Back to article page