Characteristics of the delayed respiratory syncytial virus epidemic, 2020/2021, Rhône Loire, France

Abstract

The Rhône-Loire metropolitan areas' 2020/21 respiratory syncytial virus (RSV) epidemic was delayed following the implementation of non-pharmaceutical interventions (NPI), compared with previous seasons. Very severe lower respiratory tract infection incidence among infants ≤ 3 months decreased twofold, the proportion of cases among children aged > 3 months to 5 years increased, and cases among adults > 65 years were markedly reduced. NPI appeared to reduce the RSV burden among at-risk groups, and should be promoted to minimise impact of future RSV outbreaks. The emergence of coronavirus disease (COVID-19) has triggered a wide-scale implementation of non-pharmaceutical interventions (NPI) including physical distancing, school closures, travel restrictions, and the use of masks in public spaces [1]. These preventive public health measures have impacted the circulation of respiratory syncytial virus (RSV) as demonstrated by inter-seasonal RSV epidemics in several southern hemisphere countries [2-4] and late-season RSV outbreaks in several European countries [5-7]. Here, we describe the age characteristics and the very severe lower respiratory tract infection (VS-LRTI) incidence of this late RSV epidemic in the Rhône-Loire metropolitan areas in France.