Researchers also found that 95% of respiratory syncytial virus (RSV)-associated acute lower respiratory infection episodes and more than 97% of RSV-attributable deaths were among children in low– and middle-income countries.
Respiratory syncytial virus (RSV) is linked to 1 in every 50 deaths among children aged 5 years and younger, and 1 in every 28 deaths among children aged between 28 days and 6 months, according to a systematic analysis published in The Lancet.
The authors of the analysis also estimated, for each RSV-associated acute lower respiratory infection in-hospital death, approximately 3 more RSV-attributable deaths in the community.
“RSV passive immunisation programmes targeting protection during the first 6 months of life could have a substantial effect on reducing RSV disease burden, although more data are needed to understand the implications of the potential age-shifts in peak RSV burden to older age when these are implemented,” the authors wrote.
To come to these findings, the authors conducted a systematic analysis of 481 studies published or unpublished between 2017 and 2020. All studies included data on children aged 5 years or 60 months and younger who had RSV as primary infection with acute lower respiratory infection either in community settings or requiring hospital admission.
Based on these data, the authors said an estimated 33 million RSV-associated acute lower respiratory infection episodes (uncertainty range [UR], 25.4-44.6 million) occurred globally in 2019.
In children younger than 5 years, the authors also estimated 3.6 million RSV-associated acute lower respiratory infection hospital admissions (UR, 2.9-4.6 million) and 26,300 in-hospital deaths (UR, 15,100-49,100), as well as 101,400 RSV-attributable deaths overall (UR, 84,500-125,200).
These numbers were generally lower for infants younger than 6 months, but comparable in some areas.
For this age group, the authors estimated 6.6 million RSV-associated acute lower respiratory infection episodes (UR, 4.6-9.7 million), as well as 1.4 million RSV-associated acute lower respiratory infection hospital admissions (UR, 1.0-2.0 million) and 13,300 in-hospital deaths (UR 6800-28,100), and 45,700 RSV-attributable deaths overall (38,400-55,900).
High mortality rates associated with RSV were estimated for both age groups, with 2% of deaths among children aged 60 months and younger (UR, 1.6-2.4) and 3.6% of deaths among infants aged between 28 days and 6 months (UR, 3.0-4.4) attributable to the virus.
“Based on the estimates for in-hospital and overall mortality above, we further showed that globally, only 26% of RSV-attributable deaths occurred in hospitals in children aged 0–60 months; that is three deaths in the community for every RSV-associated acute lower respiratory infection in-hospital death,” the authors said, noting that percentage is much lower than a previously estimated 50%.
It should also be noted that a vast majority of RSV-associated acute lower respiratory infection episodes (95%) and of RSV-attributable deaths (>97%) were among patients in low– and middle-income countries. The authors also discovered pronounced disparities in low-income countries, with 19% of deaths happening in hospitals, reflecting 4 community deaths for every in-hospital death.
“Most of the striking gap between in-hospital and community deaths in low-income settings can be explained by the poor access to care, cost of care, and limited beds in hospitals during an RSV epidemic,” the authors wrote. “Another explanation is that some of the RSV deaths might be in children with rapidly progressive illness who, initially, do not appear to be severely ill.”
Because of the disproportionately high burden of RSV morbidity and mortality among children younger than 6 months, the authors said further research is needed into immunizations for infants younger than 6 months, as they could potentially significantly reduce the RSV disease burden for these children.
Li Y, Wang X, Blau DM, et al. Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in children younger than 5 years in 2019: a systematic analysis. Lancet. Published online May 19, 2022. doi:10.1016/ S0140-6736(22)00478-0