Influenza A, influenza B, and SARS-COV-2 circulation patterns in midwest Brazil during the 2022-2023 period

Until 2022, the COVID-19 pandemic caused by the SARS-CoV-2, had profoundly impacted the world. Consequently, Brazil, including the state of Goiás, was also significantly affected. Furthermore, in the second half of 2022, the state of Goiás experienced an unusual rise in influenza cases, despite it being an off-season period for influenza viruses in this region. As SARS-CoV-2 and Influenza infection have similar clinical manifestations, surveillance strategies are crucial for public health. Understanding how SARS-CoV-2 and Influenza viruses co-circulate is important for surveillance and monitoring of these patterns of respiratory infections. In this context, this investigation monitored Influenza A and B cases from symptomatic individuals diagnosed as negative for COVID-19. Between September 2022 and May 2023, among the 779 samples tested, 126 (16.2%) were positive for Influenza A, whereas 93 samples (11.9%) were positive for Influenza B. In this period, the peak Influenza infection cases did not coincide with the peak of SARS-CoV-2 infections, suggesting a seasonal shift in viral circulation patterns.