Edinburgh Research Explorer

Unveiling the risk period for mortality after respiratory syncytial virus illness in young children using a self-controlled case series design

Research output: Contribution to journalArticle

Abstract

Background.
Respiratory syncytial virus (RSV)-related acute lower respiratory infection (ALRI) is an important cause of mortality in infants and young children. However, little is known about the risk period of RSV-related mortality following presentation to health services with an RSV illness.
Methods.
Using the Scottish national mortality database, we identified respiratory/circulatory deaths of young children under five years during 2009–2016 whose medical history and laboratory-confirmed RSV infections were obtained by linking the mortality database to the national surveillance dataset and the Scottish Morbidity Record (SMR). We used a self-controlled case-series (SCCS) design to evaluate the relative incidence of respiratory/circulatory mortality in the first year following an RSV episode. We defined the “risk interval” as the first year after the RSV episode and the “control interval” as the period before and after the risk interval until five years after birth. Age-adjusted incidence ratio (IR) and attributable fraction (AF) were generated using the R package “SCCS”.
Results.
We included 162 respiratory/circulatory deaths, of which 36 had a history of laboratory-confirmed RSV infection. We found that the risk of mortality decreased with time after the RSV episode and that the risk was statistically significant for the subsequent month. More than 90% of respiratory/circulatory deaths occurring within 1 week of RSV episode were attributable to RSV (AF: 93.9%, 95% confidence interval, CI: 77.6–98.4). About 80% of the respiratory/circulatory deaths occurring 1 week–1 month after RSV illness were attributable to RSV (AF: 80.3%, 95% CI: 28.5–94.6).
Conclusion.
We found an increased risk of mortality in the first month following an RSV illness episode leading to healthcare attendance. This provides a practical “cut-off” time window for community-based surveillance studies estimating RSV-related mortality. Further studies are warranted to assess the risk of mortality beyond the first month after RSV illness episode.

ID: 149114591