Impact of Infection Control Strategies on NEC and LOS in VLBW Neonates During the COVID-19 Pandemic: A Multicentre Italian Study

Background: Necrotising enterocolitis (NEC) and late-onset sepsis (LOS) are major causes of morbidity and mortality among very low birth weight (VLBW) and extremely preterm infants. The COVID-19 pandemic prompted the adoption of stringent infection control measures in neonatal intensive care units (NICUs), which may have influenced these outcomes. Objective: To evaluate whether the incidence of NEC and LOS changed during the first year of the SARS-CoV-2 pandemic compared with the year prior to the pandemic in four tertiary-level NICUs in Italy. Methods: This retrospective, multicentre observational study analysed data from 572 neonates with a gestational age (GA) ≤29 weeks and/or birth weight <1500 g, admitted to NICUs in Milan, Bologna, Naples, and Foggia in 2019 (pre-pandemic) and 2020 (pandemic). NEC and LOS were defined according to the Vermont Oxford Network (VON) criteria. Data from the VON registry were verified against hospital electronic records. Results: The mean GA of the neonates was 28 ± 3 weeks and mean birth weight was 1077 ± 343 g. NEC was diagnosed in 26 infants, with no statistically significant difference in overall incidence between 2019 and 2020. However, a significant reduction in NEC incidence was observed in one centre (NICU A) during the pandemic year (0% vs. 5.4%, p < 0.01). A total of 115 LOS cases were recorded, with coagulase-negative staphylococci being the most common pathogens. While overall LOS incidence remained stable across the two years, a marked decrease was observed in NICU C in 2020, possibly related to enhanced nurse staffing and stricter infection control practices. Conclusions: The COVID-19 pandemic-related measures did not result in significant changes in NEC or LOS incidence at the national level in this cohort. However, site-specific reductions—particularly in LOS—suggest that enhanced infection prevention protocols and improved staffing may benefit neonatal outcomes in high-incidence settings. Further studies are needed to identify which components of the infection control bundle are most effective in preventing LOS and NEC.