Table 2. Summary of evidence for short-term outcomes among within-study population comparisons.
| Outcome | Comparator 1 | Comparator 2 | Study design (no. of studies); Sample size |
Absolute difference (95% CI) | Relative risk (95% CI) |
Certainty of evidence | Conclusion | |
|---|---|---|---|---|---|---|---|---|
| Comparator 2 risk | Absolute risk differencea | |||||||
| RSV-hospitalization | ||||||||
| At-risk population | Prematurity: 29–32 wGA | Prematurity: 33–36 wGA | RC36 (n=1); 12,812 |
4.2 per 100 | NS | RR 1.20 (0.92, 1.56) |
Moderate to lowb,c,d |
Little to no difference For RSV-hospitalization in their first RSV season among infants born premature at 29–32 wGA vs. 33–36 wGA |
| At-risk vs. not-at-risk population | Prematurity: 33–36 wGA | Term: ≥37 wGA | RC42 (n=1); 599,535 |
1.2 per 100 | 1.3 more per 100 (1.1 to 1.5 more) |
RR 2.05 (1.89, 2.22) |
Moderate to lowb,c,d |
Increase RSV-hospitalization by age <24 months among infants born premature (33–36 wGA) vs. at term Among this group, infants born at 33–34 wGA had highest incidence density for RSV hospitalization at 6–12 months of age (adjusted hazard ratio [aHR] 1.74 [1.17–2.58], p<0.05) and 12–24 months of age (aHR 1.96 [1.26–3.05], p<0.05) compared to term infants |
| At-risk vs. not-at-risk population | Prematurity: <33 wGA | Term: 39–41 wGA | RFUPC37 (n=1); 443 |
1.5 per 100 | 4.3 more per 100 (0.2 to 18 more) |
RR 3.88 (1.13, 13.30) |
Very lowb,c,e |
Very uncertain For RSV-hospitalization in their first RSV season among infants born at <33 wGA vs. at term |
| Hospital length of stay, mean days | ||||||||
| At-risk population | Prematurity: 29–32 wGA | Prematurity: 33–35 wGA | PC26 (n=1); 212 |
MD 4.00 (1.54, 6.46) |
N/A | Very lowb,c,e |
Very uncertain For hospital length of stay among infants born premature at 29–32 wGA vs. 33–35 wGA and hospitalized for RSV at <12 months |
|
| At-risk vs. not-at-risk population | Prematurity: 33–36 wGA | Term: ≥37 wGA | RC42 (n=1); 7,597 |
MD 1.00 (0.88, 1.12) |
N/A | Moderate to lowb,c,d |
Small increase For hospital length of stay among infants born premature at 33–36 wGA vs. at term and hospitalized for RSV at <24 months |
|
| At-risk vs. not-at-risk population | Down syndrome | No Down syndrome | RC50 (n=1); 7,206 |
MD 3.00 (1.95, 4.05) |
N/A | Lowb,c |
Small increase For hospital length of stay for RSV among infants with vs. without Down syndrome and hospitalized for RSV at <3 years |
|
| Hospital length of stay, <1 day vs. ≥1 day | ||||||||
| At-risk population | Prematurity: 29–32 wGA | Prematurity: 33–36 wGA | RC36 (n=1); 542 |
13.9 per 100 | NS | <1 day: RR 0.86 (0.41, 1.78) |
Lowc,e |
Little to no difference For hospital length of stay <1 day among infants born premature at 29–32 wGA vs. 33–35 wGA and hospitalized in their first RSV season |
| At-risk population | Prematurity: 29–32 wGA | Prematurity: 33–36 wGA | RC36 (n=1); 542 |
86.1 per 100 | NS | ≥1 day: RR 1.02 (0.93, 1.13) |
Lowc,e |
Little to no difference For hospital length of stay ≥1 day among infants born premature at 29–32 wGA vs. 33–36 wGA and hospitalized in their first RSV season |
| ICU admission, among RSV-hospitalized population | ||||||||
| At-risk population | Prematurity: 29–32 wGA | Prematurity: 33–35 wGA | PC26 (n=1); 212 |
50.4 per 100 | NS | RR 1.03 (0.79, 1.34) |
Low to very lowb,c,d,e |
Little to no difference/very uncertain For ICU admission among infants born premature at 29–32 wGA vs. 33–35 wGA and hospitalized for RSV at <12 months |
| ICU length of stay, mean days | ||||||||
| At-risk population | Prematurity: 29–32 wGA | Prematurity: 33–35 wGA | PC26 (n=1); 169 |
MD 2.00 (-0.28, 4.28) |
N/A | Low to very lowb,c,d,e |
Small increase/very uncertain For ICU length of stay among infants born premature at 29–32 wGA or at 33–35 wGA and hospitalized for RSV at <12 months |
|
| Mechanical ventilation, among RSV-hospitalized population | ||||||||
| At-risk population | Prematurity: 29–32 wGA | Prematurity: 33–35 wGA | PC26 (n=1); 212 |
17.1 per 100 | NS | RR 1.58 (0.94, 2.65) |
Lowc,e |
Small increase For mechanical ventilation among infants born premature at 29–32 wGA vs. 33–35 wGA and hospitalized for RSV at <12 months |
| Mechanical ventilation, among ICU population | ||||||||
| At-risk population | Prematurity: 29–32 wGA | Prematurity: 33–35 wGA | PC26 (n=1); 108 |
33.9 per 100 | NS | RR 1.54 (0.99, 2.40) |
Very lowc,e,f |
Very uncertain For mechanical ventilation therapy among infants born premature at 29–32 wGA vs. 33–35 wGA and admitted to ICU for RSV at <12 months |
| Mechanical ventilation therapy duration, mean days | ||||||||
| At-risk population | Prematurity: 29–32 wGA | Prematurity: 33–35 wGA | PC26 (n=1); 45 |
MD 2.00 (-1.21, 5.21) | N/A | Very lowc,e,f |
Very uncertain For duration of mechanical ventilation therapy among infants born premature at 29–32 wGA vs. 33–35 wGA and hospitalized for RSV at <12 months |
|
| Case fatality, among RSV-hospitalized population | ||||||||
| At-risk population | Prematurity: 29–32 wGA | Prematurity: 33–35 wGA | PC26 (n=1); 212 |
0 per 100 | NS | RR 4.13 (0.17, 100.30) |
Very lowc,e.f |
Very uncertain For death due to RSV among infants born premature at 29–32 wGA vs. 33–35 wGA and hospitalized for RSV at <12 months |
| Case fatality, among ICU population | ||||||||
| At-risk population | Prematurity: 29–32 wGA | Prematurity: 33–35 wGA | PC26 (n=1); 108 |
0 per 100 | NS | RR 4.02 (0.17, 96.53) |
Very lowc,e,f |
Very uncertain For death due to RSV among infants born premature at 29–32 wGA vs. 33–35 wGA and admitted to ICU for RSV at <12 months |
Abbreviations: CI, confidence interval; ICU, intensive care unit; MD, mean difference; N/A, not applicable; no., number; NS, not significant (results failed to show a difference between groups); PC, prospective cohort; RC, retrospective cohort; RFUPC, retrospective follow-up of prospective cohort; RR, relative risk; RSV, respiratory syncytial virus; vs., versus; wGA, weeks’ gestational age
a Absolute risk reductions were calculated when findings were statistically significant; NS denotes when findings were not statistically significant
Certainty of evidence was assessed for each outcome using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Starting at high for observational studies (for prognosis evidence) each outcome is rated as high, moderate, low or very low based on downgrading (if any) for one or more of the following domains:
b Study limitations, including selective outcome reporting
c Inconsistency
d Half decrement (-0.5) due to small concern for this domain
e Imprecision
f Two decrements (-2) due to very serious concerns for this domain