Fifteen per cent of babies exposed to Zika before birth develop severe abnormalities in the first 18 months of life, according to research published in the New England Journal of Medicine.
The prospective cohort study involved symptomatic pregnant women who had Zika infection confirmed by reverse transcriptase polymerase chain reaction assay. A total of 182 Brazilian children who were exposed to Zika in utero were followed longitudinally and underwent a number of specialist tests.
Abnormal findings were identified in 39 of 115 children (34%) who underwent neuroimaging and in 35 of 94 children (37%) who also underwent neuropsychological testing. Among 94 children who underwent both neuroimaging and Bayley-III testing, neuroradiologists found that 10 (11%) had structural abnormalities, 5 (5%) had nonstructural abnormalities, and 20 (21%) had abnormal results that were limited to a nonspecific T2-weighted hypersignal on MRI.
By the age of 12-18 months, significant problems were present in seven of 112 children who were evaluated for eye abnormalities (6.25%), six of 49 children evaluated for hearing problems (12.2%) and 11 of 94 children (11.7%) evaluated for severe delays in language, motor skills and/or cognitive function. In all, 19 of 131 children (14.5%) had at least one of the three abnormalities.