*3.3. Meta-Analysis*

In the present review, out of five included studies, only three studies [25,29,32] were considered for the meta-analysis. The pooled effect of the outcome measures related to the "Environment as a major source of infection," "Invasive procedures increase the risk of nosocomial infection," "Gloves recommendation" and "Precaution standards during the procedure" is reported in Table 5. The studies which did not report the specific outcome measures were excluded from the meta-analysis [24,30].

**Table 5.** The effect size of the outcome measures.

