Space-time risk cluster and time trends of congenital syphilis in Brazil: an ecological study

Congenital syphilis (CS) is a problem of great concern for public health, especially in Brazil. The aim of this study was to analyse the time trends and the space-time dynamics of morbidity and mortality from CS in Brazil.

An ecological and time series study, which included all cases and deaths from CS recorded in a national Brazilian database from 2013 to 2019 was performed. Time trends in CS incidence and mortality were assessed using segmented linear regression. Univariate global and local Moran indices and space-time scan statistics were used in the space and space-time analyses.

A total of 183 171 cases and 2401 deaths from CS were recorded in Brazil, with the highest number of cases being observed in the Southeast Region (n=82 612 [45.1%]). Only 21.1% of pregnant mothers with syphilis received adequate treatment. There was an upward trend in CS rates among mothers ages 20-29 y (average annual percent change [AAPC] 1.4 [95% confidence interval {CI} 1.0 to 1.7]) and with <8 y of schooling (AAPC 6.6 [95% CI 5.3 to 7.9]). The primary space-time cluster involved 338 municipalities in the Southeast Region (relative risk 3.06, p<0.001) and occurred between 2017 and 2019.

To reduce the trends in CS rates, it is necessary to develop actions to improve the quality of prenatal care and expand early diagnosis and adequate treatment of syphilis in pregnant women and their sexual partners, especially in groups with upward trends (mothers ages 20-29 y and <8 y of schooling) and living in higher-risk regions (Southeast, North and Northeast).