An overview on viral interference during SARS-CoV-2 pandemic

Respiratory viruses represent the most frequent cause of mortality, morbidity and high healthcare costs for emergency visits and hospitalization in the pediatric age. Respiratory viruses can circulate simultaneously and can potentially infect the same host, determining different types of interactions, the so-called viral interference. The role of viral interference has assumed great importance since December 2019, when the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) came on the scene. The aim of this review is to present our perspective regarding research in respiratory virus interference and discuss recent advances on the topic because we are facing the co-circulation of respiratory viruses together with SARS-CoV-2. This situation can determine different clinical outcomes along with new diagnostic and therapeutic challenges. Moreover, the simultaneous circulation of different viruses can lead to different population epidemic dynamics, including changes in the age of the targeted population, disease course and severity. In this scenario, prospective epidemiologic studies and mathematical modelling able to predict the timing and magnitude of epidemics caused by SARS-CoV-2/seasonal respiratory virus interactions are more urgent than ever to adjust better public health interventions, such as the use of prophylactic agents, changes in vaccine schedules and implementation of non-pharmacologic measures.