Which Demographic, Environmental Factors Have Higher Risks for RSV Hospitalization?

When evaluating possible risk factors for respiratory syncytial virus acute lower respiratory infection (RSV-ALRI) in young children, indoor air pollution and male sex were associated with higher risks for RSV-ALRI hospitalization.¹

The researchers of this study believe it is important to identify children with risk factors for developing RSV-ALRI to optimize RSV prevention and raise awareness to the public.

This systemic review and meta-analysis is published in the International Journal of Infectious Diseases.

“Although existing evidence from community-based studies is still limited, we identified indoor air pollution as a possible risk factor for developing RSV-ALRI in the community, increasing the risk by 45%,” wrote the researchers of the study. “Besides, a wide range of demographic, pre- and post- neonatal, household and environmental, and health and medical condition related factors were identified that increased the risks for RSV-ALRI hospitalization by 14% to 355%.”

While there are no specific RSV treatments, many advances have been made in prophylactic immunization for protecting infants. For instance, the FDA approved nirsevimab-alip (Beyfortus) for prevention of RSV.² Therefore, the researchers of this study believe it is important to identify children with risk factors for developing RSV-ALRI to optimize RSV prevention and raise awareness to the public.

Based on a previous literature review, the researchers conducted an updated search from MEDLINE, EMBASE, and Web of Science to identify relevant studies published after August 1, 2015. Additionally, the researchers included 3 comprehensive and authoritative Chinese databases from January 1, 1995. All database searchers were conducted on November 30, 2022, which included all terms related to RSV, respiratory infection, child, and risk factors, as well as their synonyms. No language restrictions were applied.

A total of 5924 studies were identified. After screening and exclusion, the researchers included 21 studies from the previous review and 26 new studies (n = 47).

Indoor air pollution was identified as a possible risk factor for developing RSV-ALRI in children under 5 years (OR, 1.45; 95% CI, 1.10-1.90). Male sex was also associated with higher risks for RSV-ALRI hospitalization (OR, 1.23; 95% CI, 1.19-1.27). Another demographic factor associated with higher risks for RSV-ALRI hospitalization included Māori and Pacific ethnicity compared with European or other ethnicities.

The researchers also identified a list of pre- and post-neonatal factors including, prematurity, low birth weight, small for gestational age, maternal smoking during pregnancy or lactation, maternal age younger than 30 years vs age 30 to 34 years, multiparity, and cesarian vs vaginal birth.

Additionally, household and environmental factors included having siblings, passive smoking, maternal asthma, and daycare center attendance. Meanwhile, health and medical conditions included any chronic diseases, bronchopulmonary dysplasia, HIV infections, congenital heart disease, Down syndrome, cystic fibrosis, and previous asthma.

However, the researchers acknowledge some limitations to the study, including that more than 70% of the included studies were based on evidence from Hospital Incident Command systems, having high heterogeneities among the included studies, and the potential for confounding bias within the studies.

Despite these limitations, the researchers believe the study adds evidence of significant risk factors for RSV-ALRI hospitalizations, which may inform both public health authorities and raise awareness for high-risk individuals.

“The reported effect size of these risk factors in this study provides important input data for estimating the public health impact of reducing or eliminating certain risk factors, such as indoor air pollution,” wrote the researchers. “These data could also be used to support the development of individual risk prediction models for RSV-ALRI.”

References

1. Deng S, Cong B, Edgoose M, et al. Risk factors for respiratory syncytial virus-associated acute lower respiratory infection in children under five years: An updated systematic review and meta-analysis. Int J Infect Dis. Published online June 28, 2024. doi:10.1016/j.ijid.2024.107125

2. Bonavitacola J. FDA approves Beyfortus for Use in Infants With RSV. July 17, 2023. https://www.ajmc.com/view/fda-approves-beyfortus-for-use-in-infants-with-rsv