*Article* **Incidence of Healthcare-Associated Infections in a Neonatal Intensive Care Unit before and during the COVID-19 Pandemic: A Four-Year Retrospective Cohort Study**

**Mariateresa Ceparano 1, Antonio Sciurti 1, Claudia Isonne 1,\*, Valentina Baccolini 1, Giuseppe Migliara 1, Carolina Marzuillo 1, Fabio Natale 2, Gianluca Terrin 2, Paolo Villari <sup>1</sup> and The Collaborating Group †**


**Abstract:** The COVID-19 pandemic may have had an impact on healthcare-associated infection (HAI) rates. In this study, we analyzed the occurrence of HAIs in a neonatal intensive care unit (NICU) of the Umberto I teaching hospital in Rome before and during the pandemic. All infants admitted from 1 March 2018 to 28 February 2022 were included and were divided into four groups according to their admission date: two groups before the pandemic (periods I and II) and two during the pandemic (periods III and IV). The association between risk factors and time-to-first event was analyzed using a multivariable Cox regression model. Over the four-year period, a total of 503 infants were included, and 36 infections were recorded. After adjusting for mechanical ventilation, birth weight, sex, type of delivery, respiratory distress syndrome, and previous use of netilmicin and fluconazole, the multivariable analysis confirmed that being hospitalized during the pandemic periods (III and IV) was the main risk factor for HAI acquisition. Furthermore, a change in the etiology of these infections was observed across the study periods. Together, these findings suggest that patient management during the pandemic was suboptimal and that HAI surveillance protocols should be implemented in the NICU setting promptly.

**Keywords:** neonatal intensive care unit (NICU); healthcare associated infection (HAI); COVID-19
