Schistosomiasis, endemic in several Brazilian states, is linked to poor housing and inadequate sanitation. Early diagnosis through egg detection and antibody testing is essential to prevent fatal forms. Early diagnostic strategies for infectious diseases, however, were hindered by the emergency imposed by the COVID-19 pandemic. This study aimed to evaluate the impact of the pandemic on the epidemiological situation of schistosomiasis in endemic states of Brazil.

Cross-sectional, retrospective, quantitative study using data from the SUS Outpatient Information System and the Notifiable Diseases Information System, tabulated via DATASUS/TABNET. Data included the total number of confirmed schistosomiasis cases and the number of Schistosoma mansoni egg tests and anti–S. mansoni antibody tests recorded from 2018 to 2023 in Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe, Bahia, and Minas Gerais.

A total of 13,568 schistosomiasis cases were recorded from 2018 to 2023, with Minas Gerais (68%; n=9,320), Bahia (13.9%; n=1,889), and Pernambuco (7%; n=955) accounting for most cases. There was a 34.7% drop in cases between 2018–2019 (n=5,329) and 2020–2021 (n=3,482), followed by a 36.6% increase in 2022–2023 (n=4,757). Except for Paraíba, all states showed a decrease in cases from 2019 to 2020 and an increase in 2021. Significant increases were observed between 2018–2019 and 2022–2023 in Paraíba (122.4%), Bahia (37.4%), and Rio Grande do Norte (17.5%). Egg testing was the most used diagnostic method (n=246,005) and showed a 65% reduction in 2020–2021 compared to the prior biennium. Antibody testing was the second most used method (n=95,516) and decreased by 50% in the same period. In the post-pandemic period, the number of both tests remained below pre-pandemic levels.

The reduction in recorded cases and in diagnostic testing during the pandemic biennium suggests underreporting associated with the redirection of health efforts to manage other conditions. Policy reform and further studies are recommended to investigate potential underreporting and to evaluate whether the reduction in diagnostic testing persists in the post-pandemic biennium.