Epidemiological Profile of Rapid Influenza Tests in Brazilian Hospitals and Outpatient Units: Insights from the Diagnostic Medicine and Health Network between 2019 and 2023 (Atena Editora)

Abstract

The coexistence of viral agents in the post-covid-19 period has attracted the attention of specialists in different regional outbreaks. In this work, we evaluated rapid test requests that simultaneously screen for Influenza A, B and A (H1N1) in patients in hospital and outpatient units treated by a nationwide diagnostic and healthcare company. Using an internal database without individual identification, we analyzed medical requests for rapid influenza testing for serotypes A/B/H1N1 (Ag A/B/A-H1N1) comparing findings from January 2019 to April 2023. We analyzed the number of tests, regions, gender, age, positive cases and seasonality. We also evaluate the profile of test applicants over time. During the period evaluated, we had 4257 tests carried out in 27 cities in Brazil. The general average age in the period was 26.8 years old, with the female gender being the main one - an exception in 2020 and 2021 (47.6% and 43.6%). The prevalence of positivity was constant without significant difference over the period, with an average of 8.6% over the five years evaluated. In 2023 we detected a prevalence of 10.6%, the highest in the study. We jumped from 8 to 239 positive tests comparing 2019 and 2023, which demonstrates greater circulation of the virus due to measures to relax social isolation in the post-covid-19 period. Among influenza serotypes, we had a prevalence of group A in all years with the exception of 2023, where group B was prevalent (58.1%). H1N1 cases were detected in 0.1% of tests. Lower demand for the test coincided with the peak periods of Covid-19 and greater requests from the first quarter of 2022. Test applicants grew annually, showing interest from other specialties in the topic, with a total of 12 prescribing medical specialties in the period. The data shows the expansion of surveillance by specialties in the post-covid period and reinforces rapid testing as a screening tool in urgent and emergency situations.