Background: Respiratory syncytial virus (RSV) is one of the most common viral respiratory infections globally, with a rising incidence among children under five years of age. This study aimed to describe RSV and subsequent wheezing burden in toddlers infected between the ages of 6 and 24 months and their parents.Methods: An international cross-sectional survey was conducted from February to April 2023 across the US, UK, Spain, and Italy, recruiting parents of children under 6 years old. In this secondary analysis, data from 1,032 respondents were analyzed and separated into two groups: parents of children who had no history of bronchiolitis or RSV (n=600), and parents of children diagnosed with bronchiolitis/tested RSV-positive between 6 and 24 months of age (n=432).The collected data covered the sociodemographic and medical profiles of parents and toddlers, an evaluation of wheezing, parents’ perceptions of healthcare utilization, the impact of wheezing on both the child’s and family’s life and costs, parental awareness of RSV and preventive measures, and perceived unmet needs. Multivariable logistic regression analyses were performed to evaluate the association between RSV and wheezing.Results: Toddlers had their RSV diagnosis at a mean age of 14.6 months. 40% of children in the RSV group were hospitalized for their RSV infection, with a median stay of 5 days. Of those hospitalized, 39% were admitted to a PICU and 59% were placed on ventilatory support. Most children in the RSV group (59%) developed short- or long-term complications due to RSV.A history of wheezing was reported for 38% of children, with a higher proportion (p<0.001) in the RSV group (59%) than in the reference group (24%), and this trend was observed across countries: US (60% vs 27%, p<0.001), UK (82% vs 33%, p<0.001), Spain (54% vs 21%, p<0.001) and Italy (42% vs 14%, p<0.001). The proportion of wheezing increased with RSV severity, affecting 73% of those hospitalized with severe RSV, and 76% of those admitted in PICU. The odds of wheezing were 4.21 (3.18-5.60, p<0.001) times higher in the RSV group compared to the reference group; 4.08 (2.73-6.13) times higher for children infected between 6 to 11 months and 3.98 (2.91-5.47) times higher for those infected between 12 to 24 months (both p < 0.001).All aspects of parents' lives were significantly more affected (p<0.05) by wheezing in the RSV group than in the reference group, especially professional life (24% vs 11% reporting a major to severe impact) and social life (29% vs 15%). Wheezing had also a greater impact (p<0.001) on all aspects of children's lives in the RSV group, with 79% of those children missing at least one day of school, compared to 57% in the reference group. Parents from the RSV group were significantly more aware of preventive option for RSV infection (35% vs 26%, p=0.011). Conclusion: Wheezing represents a considerable burden for toddlers and their families and appears to be more frequent and more impactful in children with RSV history, emphasizing the need for early RSV prevention and management strategies.
