Respiratory Viruses Coinfections During the COVID-19 Pandemic in Southern Brazil

Since December 2019, the COVID-19 pandemic caused by SARS-CoV-2 has reached approximately 769 million people, leading to more than 7 million deaths worldwide. Faced with the possibility of other respiratory pathogens co-infecting patients and modifying their clinical response to SARS-CoV-2, some researchers have explored this line of investigation. The relationship between these co-infections remains unclear, underscoring the need to deepen our understanding of interactions among pathogens and between pathogens and the host. Thus, the present study employed RT-qPCR to assess the presence of Human Adenovirus (HAdV), Influenza A (Flu A), Influenza B (Flu B), Human Metapneumovirus (HMPV), Respiratory Syncytial Virus (RSV), Human Rhinovirus (HRV), and Parainfluenza Virus (PIV). Nasopharyngeal samples (187) from adult patients exhibiting respiratory symptoms were collected between February 2021 and November 2022 at the University Hospital Polydoro Ernani de São Thiago in Florianópolis, SC, Brazil. The present findings revealed that 25.16% of samples tested positive for non-SARS-CoV-2 respiratory viruses (29.8%—HRV; 5.3%—PIV; 4.3%—RSV; and 1.1%—HMPV). In the 74.84% of SARS-CoV-2-positive patients, co-infection was observed in 9.7% of patients, with 7.5% being HRV, 1.1% HAdV, and 1.1% Influenza A. Since co-infections can potentially alter patient prognoses and impact local epidemiological dynamics, this study highlights the significance of ongoing monitoring and epidemiological assessment through genomic surveillance of other clinically relevant respiratory pathogens.