Zika virus screening during pregnancy: Results and lessons learned from a screening program and a post‐delivery follow‐up analysis (2016–2022)

Abstract Objective To evaluate a Zika virus screening program applied to asymptomatic exposed pregnant women. Methodology Analysis of data generated during the roll out of a Zika screening program. We included socio‐demographic data, ultrasounds, and serological results (IgM, IgG, and Plaque Reduction Neutralization Test; PRNT) from asymptomatic pregnant women exposed to Zika virus enrolled in the screening program between 2016 to 2019. Results We included 406 asymptomatic ZIKV‐exposed pregnant women who gave 400 full‐term new‐borns. The median age was 30 years (IQR = 25–34), which was lower (29 years; IQR = 24–34) among women of non‐EU migrant origin (76.4% of the sample). Migrant women tended to delay the first pre‐natal consultation compared to EU origin women ( p = .003). Overall, 83.2% ( N = 328) of participants had ZIKV low risk serological profile (IgM−/IgG− or IgM−/IgG+ and PRNT‐), 3.0% ( N = 12) showed high risk of recent ZIKV infection (IgM+ or PRNT+) and 13.7% ( N = 54) had indeterminate results. A fetal malformation was identified in 29 children (9.3%). Fetal malformation was associated with a ZIKV high risk serological profile [24 out of the 246 (1.6%) with low risk profile and 3 out of the 12 with at high risk profile (25.0%; p = .02)]. Four newborns with high risk profile had a positive ZIKV‐PCR test, which included two cases with microcephaly. No association was observed between maternal exposure to ZIKV infection and developmental abnormalities during the post‐natal period follow‐up. Conclusions The ZIKV‐screening program had considerable costs and yielded a high rate of indeterminate results among asymptomatic pregnant women. Considering the poor value for decision‐making of the results, efforts should focus on providing early access to routine maternity care, especially to migrant women. A simpler screening protocol might consider an initial ZIKV‐PCR or IgM determination and subsequent referral to a fetal medicine specialist in those women with a positive result and/or whom ultrasound examination has revealed fetal abnormalities (10% of total women in our study sample).