Epidemiological characteristics of respiratory viruses in patients with acute respiratory infections during 2009–2018 in southern China

•Nasopharyngeal swab is most suitable for respiratory virus surveillance.•Flu prevalence was high in 2009 and afterwards remained at a low level.•RSV epidemic was notably high in 2014 and became the most predominant virus in 2014–2018.•A high prevalence of HCoV, RSV and HBoV may be related to new strains introduction. Acute respiratory infections (ARIs) remain a significant public threat with high morbidity and mortality worldwide; viruses are significant pathogens that cause ARIs. This study was conducted to better understand the epidemiological characteristics of respiratory viruses circulating in southern China. We collected 22,680 respiratory samples from ARI patients in 18 hospitals in southern China during 2009–2018; seven common respiratory viruses including Flu, RSV, PIV, hMPV, ADV, HCoV, and HBoV were screened using in-house real-time PCR. Of all samples, 9760 ARI cases (9760/22680, 43.03%) tested positive for the seven common respiratory viruses. The most detected virus was Flu (14.15%), followed by RSV (10.33%) and PIV (5.43%); Flu-A, PIV3, and HCoV-OC43 were the predominant subtypes. Although most of the viruses were detected in male inpatients, Flu was more likely detected in female outpatients. Flu infection was more likely to cause URTI (upper respiratory tract infection), whereas RSV infection was more likely to cause pneumonia and bronchitis. The prevalence of Flu was particularly high in 2009. The epidemic level was found notably high in 2014–2018 for RSV, in 2016–2018 for PIV, in the summer of 2018 for ADV, in the summer of 2016 and winter of 2018 for HCoV, and in the summer of 2011 and autumn of 2018 for HBoV. The co-detection rate of the seven viruses was 4.70%; RSV, PIV, and Flu were the most commonly co-detected viruses. This work demonstrates the epidemiological characteristics of seven common respiratory viruses in ARI patients in southern China.