Table 1.

Level of evidence and strength of recommendation for RSV prophylaxis with palivizumab

	Level of evidence
I	evidence obtained by randomized controlled clinical studies and/or by systematic reviews of randomized studies
II	evidence obtained from an individual and adequately designed randomized study
III	evidence obtained by cohort studies with concurrent or historical controls, or a meta-analysis thereof.
IV	evidence obtained by retrospective, case-controlled studies or meta-analysis
V	evidence obtained from case-series studies without a control group
VI	evidence based on the opinion of authoritative experts or of committees of experts as indicated in guidelines or a consensus conference, or based on the opinion of the members of the workgroup responsible for this guideline
	Strength of recommendations
A	the performance of that particular procedure or diagnostic test is strongly recommended (it indicates a particular recommendation supported by good quality albeit not necessarily type I or II scientific evidence)
B	there is some doubt that the procedure/intervention must be always recommended, but it is thought that its execution has to attentively be considered
C	there is substantial uncertainty in favor of or against the recommendation to perform the procedure or the intervention
D	performing the procedure is not recommended
E	performing the procedure is strongly discouraged