Investigating the impact of severe maternal SARS-CoV-2 infection on infant DNA methylation and neurodevelopment

Maternal infections during pregnancy can increase the risk to offspring of developing a neurodevelopmental disorder. Given the global prevalence and severity of infection with Severe Acute Respiratory Syndrome related Coronavirus 2 (SARS-CoV-2), the objective of this study was to determine if in utero exposure to severe maternal SARS-CoV-2 infection alters infant neurodevelopmental outcomes at 12 months and to identify potential biological markers of adverse infant outcomes. Mother-infant dyads exposed to severe SARS-CoV-2 infection (requiring hospitalization) during pregnancy and age and sociodemographic matched control dyads were recruited from Monash Medical Centre, Australia in 2021/22 and prospectively assessed over 12 months. Maternal serum cytokine levels and Edinburgh Postnatal Depression Scale (EPDS) scores were assessed at birth. DNA methylation was assessed from infant buccal swabs at birth (Illumina EPIC BeadChip). Infant neurodevelopmental outcomes at 12 months were assessed using the Ages and Stages Questionnaire (ASQ-3). Mothers exposed to severe SARS-CoV-2 exhibited elevated serum IL-6 and IL-17A and higher EPDS scores than controls at birth. Infants exposed to severe SARS-CoV-2 in utero demonstrated over 3000 significant differentially methylated sites within their genomes compared to non-exposed (adjusted p-value < 0.05), including genes highly relevant to ASD and synaptic pathways. At 12 months, severe SARS-CoV-2 exposed infants scored lower on the ASQ-3 than non-exposed infants and communication and problem-solving scores negatively correlated with maternal Il-6 levels at birth. DNA methylation changes therefore unveil potential mechanisms linking infection exposure to delayed neurodevelopment and maternal serum IL-6 levels may be a potential biomarker of child developmental delay.