Low RSV Exposure In Childrens’ First Year Does Not Reduce Asthma Care Needs

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Lower levels of exposure to RSV in childrens’ initial year of life does not reduce the need for healthcare utilization for asthma up to the age of 3 years, new findings suggest.¹

These data were the result of new research designed to examine the ongoing debate on the precise cause of the association between severe RSV bronchiolitis and subsequent reports of asthma. Notably, the COVID-19 pandemic allowed researchers to observe the impact of limiting exposure to RSV, given the pandemic’s elimination of the seasonal winter RSV peak in cases during 2021.²

Talia Amram, from the school of medicine at Ben-Gurion University of the Negev in Israel, led a team of investigators for this analysis. The team’s retrospective study was conducted with the aim of analyzing children born during the COVID-19 pandemic and those born prior to this period.

“Taking advantage of the natural experiment provided by the COVID-19 pandemic this study aimed to compare the incidence of healthcare-utilization (HCU) for asthma in early childhood between children born during March–June 2020 (low RSV exposure in the first year of life, l-RSV group) and children born during the same months in the years 2014–2017 (high RSV exposure in the first year of life, H-RSV group),” Amram and colleagues wrote.¹

Design Details

The research team carried out their population-based retrospective study, evaluating nationwide data in Israel from the country’s Clalit Healthcare Services (CHS), known to cover around 52% of the country’s population as the largest state-mandated healthcare provider.

The team made comparisons between children born in the period between March - June 2020, a time noted for its low level of RSV exposure (l-RSV cohort), and children who had been born within the same months in the years 2014 - 2017, known for its high level of RSV exposure (H-RSV cohort).

The investigators looked into data extracted from CHS’s extensive electronic medical records system (MDClone), a system that contained details regarding information such as diagnoses, laboratory results, use of different medications, details related to birth and delivery, anthropometric data, and eosinophil counts determined between 6 - 18 months of age.

Their analysis involved children who met their criteria for inclusion and had fully-completed medical records available.

Overall, the researchers assessed a total of 172,463 children in this analysis, with 32,927 included in the l-RSV arm of the study and 139,536 in the H-RSV arm. The study involved use of multivariate logistic regression and Bayesian analyses.

Conclusions

The investigators’ results indicated that there was no significant distinction in patients' asthma-related healthcare use between the l-RSV and H-RSV cohorts of the study. They did note slight increases in asthma-related outcomes among some surrogates identified within the l-RSV arm, however.

The research team noted that their findings would indicate that lower levels of RSV exposure during the first year of childrens' lives did not lead to diminished asthma-related healthcare visits up to the age of 3 years, supporting the hypothesis that RSV infection in infancy may provide more of an indicator of an underlying predisposition to asthma insread of being a direct cause.

“In summary, this extensive retrospective study leveraged the COVID-19 pandemic as a natural experiment to investigate the relationship and causality between RSV exposure in the first year of life and subsequent asthma,” they wrote. “Our findings indicate that low RSV exposure in the initial year of life did not lead to a reduction in the incidence of healthcare utilizations for asthma up to the age of 3 years.”¹

References

1. ^{Amram, T., Duek, O.A., Golan-Tripto, I., Goldbart, A., Greenberg, D. and Hazan, G. (2025), The Interplay Between Respiratory Syncytial Virus and Asthma Inception: Insights Gained From the COVID-19 Pandemic. Pediatric Pulmonology e27474. https://doi.org/10.1002/ppul.27474.}
2. ^{E. Binns, M. Koenraads, L. Hristeva, et al., “Influenza and Respiratory Syncytial Virus During the COVID-19 Pandemic: Time for a New Paradigm?,” Pediatric Pulmonology 57, no. 1 (Jan 2022): 38–42, https://doi.org/10.1002/ppul.25719.}