Neurocognitive Outcome of Children Exposed to Perinatal Mother-to-Child Chikungunya Virus Infection: The CHIMERE Cohort Study on Reunion Island

Background Little is known about the neurocognitive outcome in children exposed to perinatal mother-to-child Chikungunya virus (p-CHIKV) infection. Methods The CHIMERE ambispective cohort study compared the neurocognitive function of 33 p-CHIKV-infected children (all but one enrolled retrospectively) at around two years of age with 135 uninfected peers (all enrolled prospectively). Psychomotor development was assessed using the revised Brunet-Lezine scale, examiners blinded to infectious status. Development quotients (DQ) with subscores covering movement/posture, coordination, language, sociability skills were calculated. Predictors of global neurodevelopmental delay (GND, DQ≤85), were investigated using multivariate Poisson regression modeling. Neuroradiologic follow-up using magnetic resonance imaging (MRI) scans was proposed for most of the children with severe forms. Results The mean DQ score was 86.3 (95%CI: 81.0–91.5) in infected children compared to 100.2 (95%CI: 98.0–102.5) in uninfected peers (P
Author Summary Chikungunya virus (CHIKV), an alphaviral infection transmitted by day-biting Aedes mosquitoes, is widespread in Asia and in Africa. Usually, CHIKV causes a self-limiting arthritide, except in debilitated people and in neonates, for whom it can lead to severe disease. Mother-to-child perinatal transmission of CHIKV is a rare event that can occur in the setting of large-scale outbreaks when the risk of maternal viremia at the term of pregnancy becomes non-negligible. In that event, CHIKV can give rise to neonatal infection with a probability of 50%, and prostration and encephalopathy, the two leading clinical pictures in the neonate, represent a continuum in the gradation of an undiscovered central nervous system involvement. We have followed-up 33 children infected at birth between June 2005 and April 2006 on the island of La Réunion, Indian Ocean, and 135 uninfected controls, for assessing their neurodevelopmental performance around the age of two years. Fifty-one percent of infected children had a global neurodevelopmental delay compared to 15% of uninfected peers. Multivariate analysis and neuroradiology suggest without irrefutable evidence a causal relationship between CHIKV infection and neurocognitive outcomes. Our findings suggest that CHIKV infection, acquired in the perinatal period, can cause severe disease with lifelong expected disability.