Table 1. All infants: RSV-related hospitalization rates as a function of chronologic age.
| Reference | Study design | Study population | RSV ascertainment | RSVH rates |
|---|---|---|---|---|
| Hall et al., 2013*27 | Prospective, population surveillance study from NVSN | US children <24 mo of age with ARI from 2000–2005 | Active testing by RT-PCR | Range, 13.5–25.9/1000 infants <3 mo† Range, 4.8–10.3/1000 infants 3 to <6 mo‡ Range, 3.4–5.6/1000 infants 6 to <9 mo§ Range, 2.9–3.8/1000 infants 9 to <12 mo|| |
| Stockman et al., 2012¶32 | Retrospective analysis of NHDS | US children <5 y of age with RSV-like coded hospitalization from 1997−2006 | ICD-9-CM codes for both RSV-specific and nonspecific (% calculated from NVSN data from Nov–Apr, 30% bronchiolitis and 20% pneumonia codes) | 48.9/1000 infants ≤2 mo (95% CI: 36.6, 61.2) 28.4/1000 infants 3–5 mo (95% CI: 21.3, 35.5) 13.4/1000 infants 6–11 mo (95% CI: 10.7, 16.1) |
| Rossi et al., 2007#31 | Retrospective case-control study | Italian children <4 y of age with lower respiratory tract infection from 2000–2004 | Active testing during study years with EIA | Age <3 mo associated with increased RSVH (OR, 8.46 [95% CI: 3.09, 23.19]) 3–5 mo (OR, 4.15 [95% CI: 1.51, 11.45]) 6–11 mo (OR, 2.47 [95% CI: 0.88, 6.93]; P < 0.0001) ≥12 mo (referent) |
| Law et al., 1998**29 | Prospective cohort study | Canadian infants ≤12 mo of age from 1993–1994 in 4 provinces | Active testing by EIA, DFA, and culture RSVH rates vary by Canadian province, which accounts for wide range of rates |
Range, 1.6–3.5/1000 infants <3 mo Range, 0.98–2.2/1000 infants 3 to <6 mo Range, 0.3–1.2/1000 6 to <12 mo |
| Holman et al., 2004††28 | Retrospective analysis of NHDS | US children <12 mo of age with RSV-coded hospitalization from 2000−2001 | ICD-9-CM codes specific for RSV, RSV bronchiolitis, or RSV pneumonia | 41.9/1000 infants <6 mo (95% CI: 31.7, 52.1) 12.8/1000 infants 6–11 mo (95% CI: 9.6, 16.0) |
| Fryzek et al., 2011††‡‡26 | Retrospective analysis of NHDS | US children <24 mo of age with RSV-coded hospitalization from 1998−2006 | ICD-9-CM codes specific for RSV, RSV bronchiolitis, or RSV pneumonia | RR, 4.88 for infants <3 mo RR, 3.49 for infants 3–6 mo >6 to <12 mo (referent) |
| Paramore et al., 2004§§30 | Retrospective analysis of 3 US federally funded databases | US children <5 y of age with RSV-coded hospitalization in 2000 | ICD-9-CM codes specific for RSV, RSV bronchiolitis, or RSV pneumonia | 32.03/1000 infants <3 mo 19.26/1000 infants 3–6 mo 9.12/1000 infants 6–12 mo (referent) |
| Vicente et al., 2003††33 | Retrospective analysis of discharge records from a public hospital | Spanish children <5 y of age with hospitalization from 1996–2000 | ICD-9-CM codes specific for bronchiolitis and acute bronchiolitis | 46.7/1000 infants <3 mo 36.8/1000 infants <6 mo 25.5/1000 infants <12 mo (referent) |
ARI, acute respiratory infection; DFA, direct fluorescent antibody; EIA, enzyme immunoassay; ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification; NHDS, National Hospital Discharge Survey; NVSN, New Vaccine Surveillance Network; OR, odds ratio; RR, relative rates; RSV, respiratory syncytial virus; RSVH, respiratory syncytial virus hospitalization; RT-PCR, reverse transcriptase polymerase chain reaction. *10% of infants were preterm. †Confidence intervals for the 3-mo age groupings were not published. Hall et al.27 defined a child as being <1 mo of age if the child had not yet reached age 1 mo, 1 mo of age if the child was 1 to <2 mo of age, etc. The following hospitalization rates per 1000 children and 95% CI (rate [95% CI]) for the individual month age groups were reported from this study as: <1 mo, 13.5 (10.3, 17.1); 1 mo, 25.9 (21.3, 30.8); 2 mo, 14.3 (11.1, 17.8). ‡Hospitalization rates and 95% CI (rate [95% CI]): 3 mo, 10.3 (7.7, 13.5); 4 mo, 8.9 (6.3, 11.8); 5 mo, 4.8 (2.9, 7.0). §Hospitalization rates and 95% CI (rate [95% CI]): 6 mo, 4.1 (2.5, 6.2); 7 mo, 5.6 (3.6, 8.0); 8 mo, 3.4 (1.8, 5.2). ||Hospitalization rates and 95% CI (rate [95% CI]): 9 mo, 3.8 (2.1, 6.0); 10 mo, 3.7 (2.0, 5.7); 11 mo, 2.9 (1.5, 4.8). 4% of infants had congenital heart disease, chronic respiratory distress, or premature birth. #11.7% of infants were preterm. **18% of infants were preterm. ††Study did not mention whether data included information from preterm infants. ‡‡Additional data were provided by JP Fryzek by personal communication on June 3, 2013. §§0.3% of infants were preterm.