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 versus 91.8 ± 11.3, p = 0.043). Among them, 6 (32%) presented a mild to moderate cognitive deficit (FSIQ 71–85) and five (26%) a severe cognitive deficit (FSIQ ≤70) indicating intellectual disability. Infected children exhibited lower adaptive functioning and scored higher for hyperactivity/inattention. Interpretation These results shed light on the long-term persistent disabilities of children perinatally infected with chikungunya. Funding Centre Hospitalier Universitaire Réunion.