Mapping the risk of Zika virus infections in pregnant persons and microcephaly in newborns in relation to socioeconomic indicators in Recife, Pernambuco, Brazil: A spatial analysis (2015 to 2021)

Objective: Using spatial analysis techniques, this study investigates the associations between socioeconomic indicators measured at the census tract level and the incidence of Zika virus (ZIKV) infection in pregnant persons and microcephaly in newborns in Recife, Pernambuco, Brazil, from 2015 to 2021. Methods: In this ecological study, data on cases of ZIKV infections among pregnant persons registered in the Brazilian Information System for Notifiable Diseases (Sistema de Informação de Agravos de Notificaçao, SINAN-Zika) and cases of microcephaly among live births registered in the Public Health Event Registration System (Registro de Eventos em Saúde Pública, RESP-Microcefalia) and the Live Birth Information System (Sistema de Informações Sobre Nascidos Vivos, SINASC) were georeferenced based on residential address and aggregated within census tracts. Spatial autocorrelation was performed using the bivariate global and local Moran’s I indices, which considered the incidence rates of maternal ZIKV infections and microcephaly during the epidemic (2015–2017) and post-epidemic (2018–2021) time periods in relation to each other as well as social, economic, sanitation, and urban infrastructure covariates derived from the 2010 census. Results: From 2015 to 2021, the city of Recife registered 253 cases (n = 240 in 2015–2017 and n = 13 in 2018–2021) of ZIKV infection in pregnant persons and 147 cases (n = 137 in 2015–2017 and n = 10 in 2018–2021) of microcephaly in newborns. The global bivariate Moran’s I index between the incidences of ZIKV infection in pregnant persons and microcephaly were 0.127 (p = 0.001) in 2015–2017 and 0.074 (p = 0.002) in 2018–2021, indicating a positive spatial correlation, as higher was the ZIKV infection in pregnant persons, higher was the incidence of microcephaly. Furthermore, incidences of maternal ZIKV infection and microcephaly were consistently associated with indicators of greater social vulnerability and economic deprivation at the census tract level. Conclusion: During the epidemic and post-epidemic periods in Recife, cases of ZIKV in pregnant persons and microcephaly were concentrated in census tracts with relatively higher socioeconomic vulnerability, reinforcing the need for research to inform the development of social protection and environmental policies to mitigate ZIKV-related risks. Author summary: When cities lack proper planning, land use becomes disorganized, which creates ideal conditions for mosquitoes to thrive and spread diseases — especially affecting poorer communities. This study looked at how social and economic factors are connected to Zika virus infections in pregnant women and cases of microcephaly in babies in Recife, Brazil, between 2015 and 2021. The results showed that areas with higher poverty had more cases of Zika in pregnant women and more babies born with microcephaly. This highlights the strong link between social inequality and health problems. Both during and after the Zika outbreak, these issues continued to affect the most vulnerable neighborhoods in the city. These findings show how important it is to invest in public policies that improve living conditions and protect people socially and environmentally. Such actions are key to reducing the risk of Zika and other similar diseases, especially in the communities that need the most support.