Zika virus vertical transmission in children with confirmed antenatal exposure
Patrícia Brasil1, Zilton Vasconcelos2, Tara Kerin3
1Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. patricia.brasil33@gmail.com.
Insights
Zika virus (ZIKV) vertical transmission occurred frequently in infants born during the Rio epidemic. However, laboratory-confirmed ZIKV infection did not necessarily correlate with infant abnormalities.
Area of Science:
- Virology
- Pediatrics
- Public Health
Background:
- The 2015-2016 Zika virus (ZIKV) epidemic in Rio de Janeiro highlighted concerns regarding vertical transmission.
- Understanding the frequency and implications of ZIKV vertical transmission is crucial for infant health outcomes.
Purpose of the Study:
- To investigate the rate of Zika virus vertical transmission in infants born to infected mothers.
- To assess the association between laboratory-confirmed ZIKV infection and clinical abnormalities in infants.
- To evaluate diagnostic test performance for ZIKV infection in infants.
Main Methods:
- Longitudinal study of 130 infants born to PCR-positive mothers during the Rio de Janeiro ZIKV epidemic.
- Analysis of infant serum and urine specimens using quantitative reverse transcriptase polymerase chain reaction (PCR) and IgM Zika MAC-ELISA.
- Evaluation of diagnostic concordance, sensitivity, and specificity for ZIKV detection.
Main Results:
- Zika virus vertical transmission was detected in 65% of infants, with positivity rates higher within the first three months of life.
- Maternal infection in earlier trimesters was associated with positive infant test results.
- No significant association was found between laboratory-confirmed ZIKV infection and the presence of clinical abnormalities in infants.
Conclusions:
- Vertical transmission of Zika virus is common, but not always detectable through standard laboratory assays.
- Infant clinical outcomes are not strongly predicted by laboratory confirmation of ZIKV infection alone.
- Further research is needed to understand the full spectrum of ZIKV effects on infant health.
Abstract:
We report Zika virus (ZIKV) vertical transmission in 130 infants born to PCR+ mothers at the time of the Rio de Janeiro epidemic of 2015-2016. Serum and urine collected from birth through the first year of life were tested by quantitative reverse transcriptase polymerase chain reaction (PCR) and/or IgM Zika MAC-ELISA. Four hundred and seven specimens are evaluated; 161 sera tested by PCR and IgM assays, 85 urines by PCR. Sixty-five percent of children (N = 84) are positive in at least one assay. Of 94 children tested within 3 months of age, 70% are positive. Positivity declines to 33% after 3 months. Five children are PCR+ beyond 200 days of life. Concordance between IgM and PCR results is 52%, sensitivity 65%, specificity 40% (positive PCR results as gold standard). IgM and serum PCR are 61% concordant; serum and urine PCR 55%. Most children (65%) are clinically normal. Equal numbers of children with abnormal findings (29 of 45, 64%) and normal findings (55 of 85, 65%) have positive results, p = 0.98. Earlier maternal trimester of infection is associated with positive results (p = 0.04) but not clinical disease (p = 0.98). ZIKV vertical transmission is frequent but laboratory confirmed infection is not necessarily associated with infant abnormalities.
