During 2022, Omicron became the dominant SARS-CoV-2 variant in Europe. This study aims to assess the impact of such variant on severe disease from SARS-CoV-2 compared with the Delta variant in Italy. Using surveillance data, we assessed the risk of developing severe COVID-19 with Omicron infection compared with Delta in individuals aged ≥12 years using a multilevel negative binomial model adjusting for sex, age, vaccination status, occupation, previous infection, weekly incidence, and geographical area. We also analyzed the interaction between the sequenced variant, age, and vaccination status. We included 21,645 cases of SARS-CoV-2 infection where genome sequencing found Delta (10,728) or Omicron (10,917), diagnosed from November 15, 2021 to February 01, 2022. Overall, 3,021 cases developed severe COVID-19. We found that Omicron cases had a reduced risk of severe COVID-19 compared with Delta cases (incidence rate ratio [IRR] = 0.77; 95% confidence interval [CI]: 0.70-0.86). The largest difference was observed in cases aged 40-59 (IRR = 0.66; 95% CI: 0.55-0.79), while no protective effect was found in those aged 12-39 (IRR = 1.03; 95% CI: 0.79-1.33). Vaccination was associated with a lower risk of developing severe COVID-19 in both variants. The Omicron variant is associated with a lower risk of severe COVID-19 compared to infection with the Delta variant, but the degree of protection varies with age.

Background: Vaccine-induced SARS-CoV-2-anti-spike antibody (anti-S/RBD) titers are often used as a marker of immune protection and to anticipate the risk of breakthrough infections, although no clear cut-off is available. We describe the incidence of SARS-CoV-2 vaccine breakthrough infections in COVID-19-free personnel of our hospital, according to B- and T-cell immune response elicited one month after mRNA third dose vaccination. Methods: The study included 487 individuals for whom data on anti-S/RBD were available. Neutralizing antibody titers (nAbsT) against the ancestral Whuan SARS-CoV-2, and the BA.1 Omicron variant, and SARS-CoV-2 T-cell specific response were measured in subsets of 197 (40.5%), 159 (32.6%), and 127 (26.1%) individuals, respectively. Results: On a total of 92,063 days of observation, 204 participants (42%) had SARS-CoV-2 infection. No significant differences in the probability of SARS-CoV-2 infection for different levels of anti-S/RBD, nAbsT, Omicron nAbsT, or SARS-CoV-2 T cell specific response, and no protective thresholds for infection were found. Conclusions: Routine testing for vaccine-induced humoral immune response to SARS-CoV-2 is not recommended if measured as parameters of ‘protective immunity’ from SARS-CoV-2 after vaccination. Whether these findings apply to new Omicron-specific bivalent vaccines is going to be evaluated.

Evaluating how a COVID-19 seasonal vaccination program performed might help to plan future campaigns. This study aims to estimate the relative effectiveness (rVE) against severe COVID-19 of a seasonal booster dose over calendar time and by time since administration. We conducted a retrospective cohort analysis among 13,083,855 persons aged ≥60 years who were eligible to receive a seasonal booster at the start of the 2022-2023 vaccination campaign in Italy. We estimated rVE against severe COVID-19 (hospitalization or death) of a seasonal booster dose of bivalent (original/Omicron BA.4-5) mRNA vaccines by two-month calendar interval and at different times post-administration. We used multivariable Cox regression models, including vaccination as time-dependent exposure, to estimate adjusted hazard ratios (HR) and rVEs as [(1-HR)X100]. The rVE of a seasonal booster decreased from 64.9% (95% CI: 59.8-69.4) in October-November 2022 to 22.0% (95% CI: 15.4-28.0) in April-May 2023, when the majority of vaccinated persons (67%) had received the booster at least 4-6 months earlier. During the epidemic phase with prevalent circulation of the Omicron BA.5 subvariant, rVE of a seasonal booster received ≤90 days earlier was 83.0% (95% CI: 79.1-86.1), compared to 37.4% (95% CI: 25.5-47.5) during prevalent circulation of the Omicron XBB subvariant. During the XBB epidemic phase, rVE was estimated at 15.8% (95% CI: 9.1-20.1) 181-369 days post-administration of the booster dose. In all the analyses we observed similar trends of rVE between persons aged 60-79 and those ≥80 years, although estimates were somewhat lower for the oldest group. A seasonal booster dose received during the vaccination campaign provided additional protection against severe COVID-19 up to April-May 2023, after which the incidence of severe COVID-19 was much reduced. The results also suggest that the Omicron XBB subvariant might have partly escaped the immunity provided by the seasonal booster targeting the original and Omicron BA.4-5 strains of SARS-CoV-2.

In Italy, despite the documented positive effects of rotavirus (RV) vaccination on reducing the burden of RV disease, an updated national assessment of its impact on clinical outcomes is still lacking. This study aims to analyze the implementation of RV vaccination in Italy, evaluating its impact on discharges for acute pediatric gastroenteritis (AGE). A retrospective analysis, including hospital discharge records and data on vaccination coverage for children aged 0–71 months from 2009 to 2019, was conducted. We examined trends in hospital discharge standardized incidence before and after vaccine introduction using a negative binomial mixture model with fixed effects to evaluate the impact of universal vaccination. The percentage of vaccination coverage increased over the years, from <5% between 2009 and 2013 to 26% in 2017, reaching 70% in 2019. The standardized incidence of discharges decreased over the period from 16.6/100,000 inhabitants in 2009–2013 to 9.9/100,000 inhabitants in 2018–2019. In this phase, about 15% of the estimated hospital discharges were avoided compared with those estimated in the first phase. The implementation of RV vaccination reduced AGE incidence discharges in children aged 0–71 months. Further efforts are needed to continue monitoring the vaccination effect over time and to increase vaccination coverage.

Background/Objectives: Hand hygiene (HH) is pivotal in mitigating infectious disease transmission and enhancing public health outcomes. This study focuses on detailing the national surveillance system for alcohol-based hand rub (ABHR) consumption in healthcare facilities across Italy, presenting results from a comprehensive three-year evaluation period, from 2020 to 2022. It aims to delineate this surveillance system and report on ABHR consumption trends in various Regions/Autonomous Provinces (Rs/APs). Methods: ABHR consumption data, collected through the ABHR Italian national surveillance system, coordinated by the Istituto Superiore di Sanità (ISS), were analyzed. Statistical methods, e.g., the Mann–Whitney test, were used to assess trends in ABHR consumption, expressed in liters per 1000 patient days (L/1000PD). Results: The results show significant variation in ABHR consumption across Rs/APs and over the years studied. National median ABHR consumption decreased from 2020 to 2022, with a significant reduction from a median of 24.5 L/1000PD in 2020 to 20.4 L/1000PD in 2021 and 15.6 L/1000PD in 2022. Conclusions: The decline in ABHR consumption raises concerns about the ongoing adherence to HH practices in Italian healthcare settings. This underscores the essential role that systematic ABHR monitoring and improved surveillance play in enhancing HH compliance, suggesting that sustained and strategic efforts are fundamental to uphold high standards of hygiene and to effectively respond to fluctuating ABHR usage trends over time. Further research is needed to explore barriers to effective ABHR use and to develop targeted strategies to improve HH practices.

Background/Objectives: A resurgence of measles has been observed in Europe and worldwide since 2023. The aim of this article is to describe characteristics of cases reported to the Italian national measles surveillance system and discuss reasons for the outbreak and its public health relevance. Methods: We analyzed measles cases reported to the Italian national measles surveillance system with a symptom onset from August 2023 to January 2025. Results: Overall, 1164 cases were reported, of which 1065 (91.5%) were laboratory confirmed. The median age was 30 years, but the highest incidence was in children under one year of age. Transmission occurred mainly in families and nosocomial settings. Multiple importations occurred during 2023, which initially led to localized outbreaks with limited spread but was subsequently followed by increasing local transmission in 2024. Conclusions: These findings suggest lingering immunity gaps in children and adults in Italy, highlighting the potential severity of measles and the ease with which measles crosses country borders. Besides improving routine immunization coverage, targeted vaccination opportunities should be provided to susceptible population groups. Communication activities are also needed to increase awareness about disease severity, especially among young adults. In view of the upcoming travel season, travel clinics should encourage persons without evidence of measles immunity to be vaccinated before any international travel.