1671. Impact of Zika Syndrome on Brazilian Infant Mortality Rate

BACKGROUND: Infant mortality in Brazil has increased for the first time in 26 years. This study aimed to define the Zika Syndrome (ZS) perinatal case fatality rate (PCF) since the 2015 Zika outbreak in a Brazilian northeast state highly impacted by the virus. METHODS: Cross-sectional study conducted using data obtained through the State Health Department for cases of microcephaly (MCP) and congenital abnormalities (CA) in Rio Grande do Norte State (RN) from April 2015 to March 2, 2019. Perinatal period: commencing at 22 completed weeks (154 days) of gestation until 7 days after birth. PCF was defined as the number of deaths as a fraction of the number of sick persons with the specific disease (×100). RESULTS: There were 535 reported cases of MCP and others CA notified in RN during this period: 4 in 2014, 337 in 2015, 157 in 2016, 21 in 2017, 14 in 2018, and 2 in 2019. Of these, 151 were confirmed and 135 remain under investigation. The remaining 247 cases were ruled out by normal physical exams or due to noninfectious cause of MCP. Of the total confirmed cases, 35.8% (54/151) died after birth or during pregnancy. Zika virus infection during pregnancy was confirmed in 55.5% (30/54) of deaths and 1.8% (01/54) had a positive TORCH blood test. The odds ratio for the Zika PCF was found to be 1.57 (95% CI: 0.7940–3.1398; P = 0.1928). Deaths related to Zika were confirmed using a combination of clinical and epidemiological findings paired with either radiological information or molecular/serological data (RT–PCR and/or IgM/IgG antibodies against Zika). Twelve cases remain under investigation and 7 were ruled out as MCP. The highest number of confirmed MCP cases occurred between August 2015 and February 2016. The prevalence increased in September, with a peak in November 2015 (20.1 cases per 1,000 live births). CONCLUSION: Before the recent Brazilian Zika outbreak, the incidence of MCP in RN between 2010 and 2014 was 1.8 cases/year. The real incidence and prevalence might be higher due to the underreporting and lack of resources for confirmatory diagnostic tests (laboratory and imaging). This study indicates that Zika virus accounted for a substantial proportion of MCP cases seen during the years studied, and suggests that ZS contributed to an increase in infant mortality in Brazil. [Image: see text] DISCLOSURES: All authors: No reported disclosures.