In a study published in Emerging Infectious Diseases on respiratory syncytial virus (RSV) surveillance in the United States, 53.4% of infants (897 out of 1,680) were infected during infancy, with 2.8% requiring hospitalization. Among those with symptoms, 44.1% experienced lower respiratory tract infections (LRTI). The overall healthcare burden was substantial, with 1.5% of the entire cohort hospitalized and 8.5% suffering from RSV-related LRTI.1
Key risk factors for RSV infection included birth month (higher risk for those born in June), presence of siblings, daycare attendance, and socioeconomic factors like neighborhood poverty and public insurance. These findings establish benchmarks for assessing the impact of maternal vaccines and extended half-life monoclonal antibodies.1
Researchers employed active surveillance (qRT-PCR testing of nasal samples based on symptom surveys) and passive surveillance (serum antibody testing at age 1) across 11 pediatric practices. In-person assessments were conducted for infants with acute respiratory infections, collecting nasal wash and blood samples for analysis. The study calculated the 1-year prevalence of RSV infections, symptomatic diseases, LRTI, and healthcare utilization, utilizing multivariable logistic regression to evaluate risk factors for infection.1
The study has limitations regarding the generalizability of its eligibility criteria and sociodemographic characteristics. The cohort primarily consists of term infants, which may reflect a healthier demographic, yet this group accounts for half of RSV hospitalizations eligible for prevention products. There is a risk of misclassifying infants deemed uninfected with RSV, although proportions of symptomatic respiratory illness and overall RSV serologic positivity align closely with other studies. The cohort spans two RSV seasons (2012–2014), but the researchers do not expect this timeframe to significantly influence infection rates or risk factors, which remained consistent across seasons.1
