Suppression of influenza virus infection by rhinovirus interference at the population, individual and cellular levels

Abstract Background Investigations of the natural viral interference effect between rhinovirus (RV) and influenza virus (IV) were conducted in temperate regions. We conducted an epidemiological study in Hong Kong, a major epicentre of influenza virus in the sub-tropical region. RV is the most prevalent respiratory virus year-round and causes asymptomatic to mild symptoms while IV infection exerts a great burden of public health. We aimed to examine the correlation of RV prevalence against IV activity. Methods Nasopharyngeal aspirates (NPA) collected from patients hospitalized in the regional hospitals from 2015 to 2019 were examined for the presence of respiratory viruses. The correlation of the monthly prevalence between all pairs of virus infection, the co-infection rate and the temporal interference of RV and IV were tested. The viral interference was validated in vitro by conducting sequential RV and IV infection in the well-differentiated primary human airway epithelial cells. Findings A total of 112,926 NPA were evaluated, and the Enterovirus/RV was the most prevalent respiratory virus detected. The negative correlation between EV/RV and IVs prevalence was independent of age and meteorological factors. Co-infection of EV/RV and IV was significantly less when compared with other virus pairs. Prior exposure to RV inhibited the replication of influenza A, B and oseltamivir-resistance stain in vitro and the inhibition is replication dependent. Interpretation Epidemiological surveillance and the sequential infection in vitro suggested viral interference between EV/RV and IV operated at the population, individual and cellular levels. Funding This study was supported by the General Research Fund (Ref: 24107017 and 14103119 to RWYC), Health and Medical Research Fund (Ref: COVID190112 to RWYC) and the Chinese University Direct Grant for Research (Ref: 2019.073 to RWYC).