The impact of RSV/SARS-CoV-2 co-infection on clinical disease and viral replication: insights from a BALB/c mouse model

Abstract

RSV and SARS-CoV-2 are prone to co-infection with other respiratory viruses. In this study, we use RSV/SARS-CoV-2 co-infection to evaluate changes to clinical disease and viral replication in vivo. To consider the severity of RSV infection, effect of sequential infection, and the impact of infection timing, mice were co-infected with varying doses and timing. Compared with a single infection of RSV or SARS-CoV-2, the co-infection of RSV/SARS-CoV-2 and the primary infection of RSV followed by SARS-CoV-2 results in protection from SARS-CoV-2-induced clinical disease and reduces SARS-CoV-2 replication. Co-infection also augmented RSV replication at early timepoints with only the low dose. Additionally, the sequential infection of RSV followed by SARS-CoV-2 led to improved RSV clearance regardless of viral load. However, SARS-CoV-2 infection followed by RSV results in enhanced SARS-CoV-2-induced disease while protecting from RSV-induced disease. SARS-CoV-2/RSV sequential infection also reduced RSV replication in the lung tissue, regardless of viral load. Collectively, these data suggest that RSV and SARS-CoV-2 co-infection may afford protection from or enhancement of disease based on variation in infection timing, viral infection order, and/or viral dose. In the pediatric population, understanding these infection dynamics will be critical to treat patients and mitigate disease outcomes.

Respiratory Viral Coinfections: Insights into Epidemiology, Immune Response, Pathology, and Clinical Outcomes

“…In a mathematical model that simulates the coinfections of some respiratory viruses like SARS-CoV-2, IAV, RSV, and RV, it was found that RSV had the most impact on the prevalence of SARS-CoV-2 when the two viruses co-circulated and that the coinfection of RSV with SARS-CoV-2 caused the largest suppression of SARS-CoV-2 infection [ 68 ]. This effect may be caused by the pre-infection of RSV, leading to the decreased replication of SARS-CoV-2 and clinical disease [ 69 ], which could mean that RSV provides some protection to SARS-CoV-2. This may be why, although there is an increase in hospital stays in patients with RSV and SARS-CoV-2 coinfection, there is no need for intensive care or mechanical ventilation [ 70 ].…”