Vaccine Hesitancy in Autism Spectrum Disorder: A Systematic Review With Meta-Analyses.

Among studies using a common instrument and threshold (PACV ≥ 50), the pooled prevalence of vaccine hesitancy among caregivers of children with autism spectrum disorder was 23.65% (95% CI 15.87-33.71).

They also had higher odds than families of children with other neurodevelopmental conditions (pooled OR = 2.23, 95% CI 1.48-3.35).

Sibling-focused analyses suggested greater under-vaccination among younger siblings in autism spectrum disorder-affected families (pooled RR = 3.20, 95% CI 2.59-3.96).

Narrative findings consistently implicated the disproven MMR-autism claim, safety concerns, and distrust.