Background and Objective:
As of January 2020, a new type of Coronavirus started to spread globally. Healthcare workers (HCWs) are exposed to a high risk of infection. Our study aims to describe the trend of SARS-CoV-2 infections within HCWs of the Azienda Ospedaliero Universitaria (AOU) delle Marche.

Methods:
We carried out an observational longitudinal study; data has been collected from the records of the Hospital Hygiene Department of the AOU delle Marche. Among all the employees with a permanent contract (3280), only those with a positive SARS-CoV-2 swab result in the period from the 17/03/2020 to 24/03/2022 have been included.

Results:
During study time, 794 operators tested positive corresponding to 23.6% of all employees (95%CI 22.0-25.3). The sample was constituted of 597 (75.19%) females and 197 (24.81%) males. There was a higher incidence among employees under 30 years of age, followed by those aged 30-39. Comparing the Sars-CoV-2 incidence in the Italian population with the HCWs’ one, the incidence in March 2020 was lower in the first group. From May 2020 to September 2020, the incidence in both populations was comparable. From December 2020, the incidence among healthcare employees decreased more drastically than in the general population and remained lower even in the following months (February - May 2021). The arrival of the Delta variant in May 2021 did not seem to affect the number of positive cases but, from November 2021 with the Omicron variant, there was a sudden increase in incidence in both groups.

Conclusions:
Although healthcare workers were more exposed to the virus and were more frequently screened, their risk of infection was not higher than the general Italian population. This was probably because of the anti-SARS-CoV2 vaccination that has been administered primarily to HCWs starting from 27/12/2020 and to stricter adherence to personal protective equipment use.