Population-based surveillance for congenital zika virus syndrome: a latent class analysis of recorded cases from 2015–2018

• Published in: BMC pregnancy and childbirth Vol. 22; no. 1; pp. 1 - 530
• Main Authors: Paixao, Enny S., Rodrigues, Laura C., Costa, Maria da Conceição N., de Carvalho-Sauer, Rita de Cassia Oliveira, Oliveira, Wanderson K., Cardim, Luciana L., Schuler-Faccini, Lavinia, Andrade, Roberto F. S., Rodrigues, Moreno S., Brickley, Elizabeth B., Veiga, Rafael V., Costa, Larissa C., Carmo, Eduardo H., Smeeth, Liam, Barreto, Mauricio L., Teixeira, Maria Gloria
• Format: Journal Article
• Language: English
• Published: London BioMed Central 29-06-2022; BMC
• Subjects: Births; Congenital zika syndrome; Epidemiology; Health surveillance; Imaging findings; Latent class analysis; Microcephaly; Mortality; Zika virus; Brazil
• ISSN: 1471-2393; 1471-2393
• DOI: 10.1186/s12884-022-04860-3

Abstract
Objective
This study aims to describe clinical findings and determine the medium-term survival of congenital zika syndrome (CZS) suspected cases.
Methods
A retrospective cohort study using routine register-based linked data. It included all suspected cases of CZS born in Brazil from January 1, 2015, to December 31, 2018, and followed up from birth until death, 36 months, or December 31, 2018, whichever came first. Latent class analysis was used to cluster unconfirmed cases into classes with similar combinations of anthropometry at birth, imaging findings, maternally reported rash, region, and year of birth. Kaplan–Meier curves were plotted, and Cox proportional hazards models were fitted to determine mortality up to 36 months.
Results
We followed 11,850 suspected cases of CZS, of which 28.3% were confirmed, 9.3% inconclusive and 62.4% unconfirmed. Confirmed cases had almost two times higher mortality when compared with unconfirmed cases. Among unconfirmed cases, we identified three distinct clusters with different mortality trajectories. The highest mortality risk was observed in those with abnormal imaging findings compatible with congenital infections (HR = 12.6; IC95%8.8–18.0) and other abnormalities (HR = 11.6; IC95%8.6–15.6) compared with those with normal imaging findings. The risk was high in those with severe microcephaly (HR = 8.2; IC95%6.4–10.6) and macrocephaly (HR = 6.6; IC95%4.5–9.7) compared with normal head size.
Conclusion
Abnormal imaging and head circumference appear to be the main drivers of the increased mortality among suspected cases of CZS. We suggest identifying children who are more likely to die and have a greater need to optimise interventions and resource allocation regardless of the final diagnoses.