Long-term neurodevelopmental outcomes of children perinatally infected with chikungunya: the CHIK13+ matched cohort study on Reunion Island.

Background: Perinatal mother-to-child chikungunya is a rare but potentially severe infection. We assessed the long-term neurodevelopmental outcomes of perinatal mother-to-child chikungunya. Methods: In an observational matched cohort study, we evaluated children born with virologically or serologically confirmed chikungunya previously enrolled in the CHIMERE or hospital-based cohorts on Reunion Island. At the age of 13 and above, children underwent assessments of neurocognitive outcomes, adaptive functioning and behavioural skills by a neuropsychologist blinded of the exposure status, using the Wechsler Intelligence Scale for Children (WISC-V), the Vineland Adaptive Behaviour Scale (VABS-II) and parent-reported Strength and Difficulties questionnaires (SDQ), respectively. Infected children were compared with propensity score matched uninfected children born in the same epidemic context. Matching was performed a priori in birth registries on perinatal variables and month of exposure. The study was registered in ClinicalTrials (NCT04909411). Findings: Of 161 children eligible to participate in the study, 42 were enrolled between January 13, 2020, and January 14, 2021. Of them, 19 infected children (6 encephalitic; 13 non-encephalitic) were matched with 19 uninfected peers. Infected children exhibited lower mean Full-Scale Intelligence Quotient (FSIQ) than uninfected peers (82.1 ± 18.4 Interpretation: These results shed light on the long-term persistent disabilities of children perinatally infected with chikungunya. Funding: Centre Hospitalier Universitaire Réunion.