Fig. 4

Funnel plot assessing publication bias in a meta-analysis of HMPV prevalence. The x-axis represents the effect size, while the y-axis represents the standard error. Open circles indicate individual studies, and shaded areas represent confidence regions. The symmetrical distribution of studies around the central axis suggests minimal publication bias, with smaller studies (higher standard error) concentrated at the top and larger studies (lower standard error) spread at the base. The presence of studies across varying standard error levels supports the methodological robustness and validity of the meta-analysis findings