Microcephaly in Australian children, 2016–2018: national surveillance study

OBJECTIVE: To describe infants aged 3 SDs). Birth defects were reported in 42 (60%). Of 49 infants with developmental assessment details available, 25 (51%) had failed to reach all milestones. Vision impairment was reported in 14 (26%). The cause of microcephaly was unknown in 60%: 13 (19%) had been diagnosed with genetic disorders; 22 (39%) had anomalies on neuroimaging. No congenital or probable Zika infection was identified. Severe microcephaly was more often associated with hearing impairment than microcephaly of >2 SDs but ≤3 SDs below the mean (p<0.007). Indigenous children and children with socioeconomic advantage were over-represented among children with microcephaly. CONCLUSION: Novel national data on microcephaly highlight the high proportion of idiopathic cases. This has implications for prevention and management and suggests the need for a standardised diagnostic approach and ongoing surveillance mechanism in Australia.