Risk Factors for Hospital Admission with RSV Bronchiolitis in England: A Population-Based Birth Cohort Study

Abstract

ObjectiveTo examine the timing and duration of RSV bronchiolitis hospital admission among term and preterm infants in England and to identify risk factors for bronchiolitis admission.DesignA population-based birth cohort with follow-up to age 1 year, using the Hospital Episode Statistics database.Setting71 hospitals across England.ParticipantsWe identified 296618 individual birth records from 2007/08 and linked to subsequent hospital admission records during the first year of life.ResultsIn our cohort there were 7189 hospital admissions with a diagnosis of bronchiolitis, 24.2 admissions per 1000 infants under 1 year (95%CI 23.7–24.8), of which 15% (1050/7189) were born preterm (47.3 bronchiolitis admissions per 1000 preterm infants (95% CI 44.4–50.2)). The peak age group for bronchiolitis admissions was infants aged 1 month and the median was age 120 days (IQR = 61–209 days). The median length of stay was 1 day (IQR = 0–3). The relative risk (RR) of a bronchiolitis admission was higher among infants with known risk factors for severe RSV infection, including those born preterm (RR = 1.9, 95% CI 1.8–2.0) compared with infants born at term. Other conditions also significantly increased risk of bronchiolitis admission, including Down's syndrome (RR = 2.5, 95% CI 1.7–3.7) and cerebral palsy (RR = 2.4, 95% CI 1.5–4.0).ConclusionsMost (85%) of the infants who are admitted to hospital with bronchiolitis in England are born at term, with no known predisposing risk factors for severe RSV infection, although risk of admission is higher in known risk groups. The early age of bronchiolitis admissions has important implications for the potential impact and timing of future active and passive immunisations. More research is needed to explain why babies born with Down's syndrome and cerebral palsy are also at higher risk of hospital admission with RSV bronchiolitis.

Járvány után – járvány előtt. Bronchiolitis előfordulása a Bács-Kiskun Megyei Kórház Csecsemő- és Gyermekosztályán

“…A csecsemők 20-30%-a átesik a fertőzésen. Norvég és egyesült királyságbeli vizsgálatok alapján a kórházi ellátást igénylő bronchiolitisek aránya 20-25/1000 csecsemő [11,12]. Hasonló gyakoriságot figyelembe véve Magyarországon évi mintegy 20-30 ezer csecsemő RSV-fertőzésével és évi mintegy 2000-2500 kórházi ellátást igénylő csecsemőkori bronchiolitissel kell számolni.…”

RSV vaccine use – the missing data

“…[13] How long the infant will remain protected after maternal immunization, however, is unclear. The median age of hospitalization for infants with RSV bronchiolitis is approximately 3 months [14] when maternal antibody has already significantly waned, [15] but the peak of hospitalization (modal age) occurs in infants at 1 month of age, [14] despite higher levels of maternal antibody being present at this age than at any other time later in infancy. [15] In addition, geographical variation in factors that influence the efficiency of transplacental antibody transfer (e.g., maternal diseases such as placental malaria) may result in geographic differences in vaccine efficacy.…”

Stemming the tide of hospital admissions for bronchiolitis

“…Rising hospital admissions, which may be symptomatic of lower clinical thresholds for admission, have been shown to have a negative correlation with LoS. There is recent evidence that LoS for bronchiolitis is low, with median LoS for bronchiolitis in the UK in 2007/2008 being only 1 day long 4 5…”

“…Another possibility is that we are discharging infants home earlier and accepting a higher risk of readmission, thus inflating the total number of admission episodes disproportionately to the number of affected infants. Recent data show 21% of infants hospitalised with bronchiolitis have more than one admission,4 but unfortunately historical administrative data is not suitable for comparison through similar linkage studies.…”