Comparing Adverse Health Outcomes in Infants Born to Women Monoinfected with Zika Virus or Infected with Both Zika and Chikungunya Viruses during Pregnancy: A Prospective Cohort Study in Pernambuco, Brazil (2015–2017)

The association between Zika virus (ZIKV) infection in pregnant women and congenital defects is well-established. However, the consequences of infection with both ZIKV and Chikungunya virus (CHIKV) during pregnancy remain poorly understood. The aim for the present study was to estimate and compare the risk of adverse outcomes in infants born to mothers infected with ZIKV alone and those born to mothers infected with both ZIKV and CHIKV during pregnancy. A cohort study was conducted, following pregnant women with rash who were reported to the Strategic Health Surveillance Information Center of the State of Pernambuco between 2015 and 2017 and underwent laboratory testing for ZIKV and CHIKV. All participants resided within a 120-kilometer radius of the city of Recife, Pernambuco, Brazil. Newborns were monitored through standardized assessments conducted by specialists from the Microcephaly Epidemic Research Group. Adverse outcomes were compared between newborns prenatally exposed to ZIKV alone and those exposed to both ZIKV and CHIKV using descriptive statistics, as well as RRs. A total of 278 children (n = 198 exposed to ZIKV alone; n = 80 exposed to ZIKV and CHIKV) were included. No significant differences were observed between the groups in the offspring's risks of microcephaly, low birth weight, prematurity, small for gestational age, dysphagia, neurological, ophthalmological, audiological, or neuroimaging abnormalities. Although previous studies have revealed that each infection independently may be associated with adverse outcomes in newborns, the present study generally revealed no difference in the frequency or type of adverse effects in children born to mothers infected with both ZIKV and CHIKV compared with those exposed only to ZIKV during pregnancy.