Incidence of ventilator-associated pneumonia in neonatal intensive care units: a systematic review and meta-analysis

Objective This paper systematically evaluated the infection rate and 1000-day infection rate of ventilator-associated pneumonia (VAP) in neonatal intensive care units (NICUs) worldwide, to provide evidence-based support for hospital infection control. Methods A systematic search was conducted in PubMed, Embase, Cochrane Library, and Web of Science from database establishment to November 2025 for studies that reported the infection rate and 1000-day infection rate of VAP among infants in the NICU. We conducted a meta-analysis using a random-effects model in R software to estimate the pooled infection rate and its 95% CI. Sources of heterogeneity were explored through subgroup analyses (by gestational age, birth weight, and underlying medical conditions) and meta-regression. Sensitivity analyses were performed using a leave-one-out approach to assess result’s robustness, and publication bias was examined using funnel plots and the trim-and-fill method. This study has been registered in PROSPERO (CRD420251235255). Results In total, 75 studies were included (of which 72 provided data on the overall VAP incidence, and 38 provided data on the 1000-day VAP incidence rate). Among infants in the NICU who were confirmed to have received invasive mechanical ventilation (53 studies, 16,724 patients), the combined incidence of VAP was 22.75% (95% CI: 18.02%–28.30%, I 2 = 95.9%); the pooled incidence per 1000 ventilator days based on 38 studies (984,209 ventilator days) was 7.3‰ (95% CI: 5.2‰–10.2‰, I 2 = 98.8%). Among all NICU infants not restricted to mechanical ventilation (19 studies, 45,280 cases), the infection rate of VAP was 2.72% (95% CI: 1.31%–5.56%, I 2 = 97.4%). Subgroup analysis revealed that among mechanically ventilated infants, the infection rate was substantially higher among preterm infants (34.45%), very low birth weight infants (36.45%), and those with respiratory distress syndrome (33.38%). Meta-regression further identified preterm status as a significant positive moderator for VAP infection rates and publication year for the per 1000 ventilator-day rate (both p < 0.05). Sensitivity analysis indicated robust results; although publication bias may exist, the effect size did not change significantly after correction using the trim-and-fill method. Conclusion VAP incidence in the NICU was 22.75%. This finding underscores high VAP incidence among mechanically ventilated neonates, which poses a significant challenge to clinical management. Preterm birth, very low birth weight, and respiratory distress syndrome are identified as the primary risk factors. Further exploration of effective prevention and control strategies is needed to improve neonatal outcomes.