SUPPLEMENTAL DIGITAL CONTENT
Search strategies (conducted on August 1, 2012)
Step 1
Search strategy for MEDLINE:
“Asthma/etiology” [Mesh] AND "Respiratory Syncytial Virus
Infections/complications"[Mesh]
Limits: Systematic Reviews or Meta-Analysis, All Infant: birth–23 months, All Child:
0–18 years, Publication Date from 2000 to 2012.
Or ("Asthma/etiology"[Majr]) AND "Respiratory Syncytial Virus Infections/
complications"[Majr]
Limits: Review, All Infant: birth–23 months, All Child: 0–18 years, Publication Date
from 2000 to 2012.
Search strategy for EMBASE:
1. Respiratory Syncytial Virus.af.
2. asthma/et [Etiology]
3. 1 and 2
4. limit 3 to yr="2000–2012"
5. limit 4 to (meta analysis or "systematic review")
6. limit 4 to ("review" and (infant or preschool child <1 to 6 years>))
7. 5 or 6
Note: Reviews identified in the first step were included if they met the following
criteria: (i) they identified articles that quantified the level of association between
RSV infection and asthma/wheezing sequelae; (ii) the maximum age at the time of
RSV infection was <3 years; (iii) articles in the review were properly referenced; (iv)
the focus of the review was RSV and not other viral infections; and (v) a clinical
outcome (not a laboratory test) was measured.
Step 2
Search strategy for MEDLINE:
(Respiratory Syncytial Virus or RSV) AND (Asthma OR wheezing) and (association
or caus* or relationship)
Limits: Humans, All Infant: birth–23 months, All Child: 0–18 years.
Field: Title/Abstract
Note: We only searched for articles that were published after the articles identified in
the first step (i.e,. from November 2010 to August 2012).
Search strategy for EMBASE:
1. (respiratory syncytial virus and (asthma or wheezing) and (association or caus* or
relationship)).ab.
2. limit 1 to yr="2010–Current"
3. limit 2 to (human and (infant or child or preschool child <1 to 6 years> or school
child <7 to 12 years>))
WinBUGS SIMULATION DETAILS
Known distributions
prevalence ~dbeta(116, 1818) (i.e., mean=6.0% and SD=0.54%)
rsv.incidence ~dbeta(17 879 * 75.3%, 17 879/1.74% – 17 879 * 75.3%) [23]
ln(or) ~dnorm(1.529312, 76.408)
Where prevalence is the asthma prevalence for all infants <5 years old,
rsv.incidence is the inpatient hospitalization rate in the first year of life, and dbeta
(116, 1818) is a beta distribution with alpha = 116 and beta = 1818.
The parameters were chosen such that the mean and SD of the prevalence were
6.0% and 0.54%, respectively, as per the National Center for Health Statistics.[22]
Alpha and beta parameters for rsv.incidence were estimated from unprojected
inpatient hospitalizations due to RSV in the first year of life and the average
incidence of RSV reported by Paramore et al.[23]
or is the odds ratio of the increased association of asthma in the first 5 years and
RSV hospitalization (calculated from meta-analysis).
Estimated distributions
asthma.nonrsv ~dbeta(alpha.nonrsv, beta.nonrsv)
asthma.rsv ~dbeta(alpha.rsv, beta.rsv)
Where asthma.rsv is the asthma prevalence for infants <5 years old who had an
inpatient hospitalization in the first year of life, and asthma.nonrsv is the asthma
prevalence for infants <5 years old who did not have an inpatient hospitalization.
Equation system to estimate parameters of the unknown distributions,
alpha.nonrsv, beta.nonrsv, alpha.rsv, and beta.rsv
alpha.nonrsv = asthma.nonrsv * (116 + 1818) * (1 – rsv.incidence)
beta.nonrsv = (116 + 1818) * (1 – rsv.incidence) – alpha.nonrsv
alpha.rsv = or * alpha.nonrsv / beta.nonrsv * beta.rsv
beta.rsv = 1818 – beta.nonrsv