2.5 Data analysis
All analyses were conducted on R statistical software (version 4.2.2),
in addition to the base package, meta, and metafor package was
used[15]. We used the random effects model to
calculate the pooled incidence rate with the inverse variance approach
and the corresponding 95% confidence intervals (CI) for the primary
outcomes of interest. The I² value represents the percentage of total
variation among studies due to heterogeneity rather than chance. After
that, the random effects models were used because of the underlying
heterogeneity in the studies, containing types of neuroimmune disorders,
vaccines, and doses, and the reported outcomes (I² ≥50% or p
< 0.05). We performed subgroup analyses to ascertain if
results were effect by the type and dose of vaccine or the different
disease types. The forest plot was used to represent the result of
conducted subgroup meta-analysis graphically. Publication bias was
assessed using funnel plots, visual inspection for funnel plot
asymmetry, and Egger’s test of funnel plot asymmetry. A sensitivity
analysis was conducted to evaluate the robustness and reliability of the
results.