Vaccination strategies for high-risk and fragile populations in Lombardy (Italy): a region-wide assessment of hospital-based models and best practices.

Background: Subjects with selected underlying medical conditions are at higher risk of infection and severe outcomes from vaccines preventable diseases. While most countries adopt life-course approaches to vaccination, high-risk group immunization programmes could maximize individual protection, while contributing to population health. The COVID-19 pandemic stimulated the planning and implementation of successful hospital-based high-risk groups' immunization models. However, in Italy, high-risk subjects' vaccine coverage is not actively monitored at the national or regional level, nor shared guidelines exist yet on hospital-based immunization programmes. Study Design: The study reports findings from a region-wide assessment of the availability, characteristics, and setting-specific features of hospital-based immunization programmes for high-risk subjects in the Lombardy region. Methods: Fondazione The Bridge a not-for-profit organization based in Milan, in collaboration with the Prevention Unit of the Lombardy Region Directorate for Welfare, and the University of Pavia coordinated a project aimed at bringing together regional health institutions, key stakeholders, academic experts, scientific societies and patients' associations to assess high-risk subjects' barriers to vaccine uptake and inform preventive programmes and policies. In this context, we designed and implemented a survey to systematically map the existence and characteristics of hospital-based immunization programmes targeting high-risk subjects. The survey was proposed to all 115 hospital medical directions of the Lombardy region. Results: We collected data from 97 hospital medical directions, with a response rate of 85%. Among respondents, 24% were publi-cly managed hospitals, 17% were Scientific Institute for Research, Hospitalization and Healthcare (IRCCS) and 59% accredited private hospitals. Overall, 51.5% facilities in the Lombardy Region reported to actively administer vaccines to high-risk subjects in hospital settings, the prevalence being 89.6% in public hospitals. Among hospitals where vaccines are actively administered, 46% reported to have centralized vaccines ambulatory clinics, while 54% reported to administer vaccines in the context of inpa-tient care, within clinical wards. In 14% of hospitals vaccination counselling is carried out at the hospital level, while patients are referred to community services for the vaccine administration, 58% have established clinical pathways and formalized internal procedures to integrate vaccine prevention within the clinical care. Conclusions: Half of hospital facilities in the Lombardy Region administer vaccines to high-risk patients. Hospital-based im-munization models vary widely by vaccines programmes, organizational aspects, vaccines procurement and workforce involved. Identifying best practices and effective models can help tackle current challenges and improve immunization coverage for at-risk groups.

Protective action of natural and induced immunization against the occurrence of delta or alpha variants of SARS-CoV-2 infection: a test-negative case-control study.

BACKGROUND: The evolution of SARS-CoV-2 has led to the emergence of several new variants, and few data are available on the impact of vaccination on SARS-CoV-2 variants. We aimed to assess the association between natural (previous infection) and induced (partial or complete vaccination) exposure to SARS-CoV-2 and the onset of new infection supported by the delta variant, and of comparing it with that supported by alpha. METHODS: We performed a test-negative case-control study, by linking population-based registries of confirmed diagnoses of infection with SARS-CoV-2, vaccinations against Covid-19 and healthcare utilization databases of the Italian Lombardy Region. Four hundred ninety-six persons who between 27 December 2020 and 16 July 2021 had an infection by the delta variant were 1:1 matched with citizens affected by alphavariant and 1:10 matched with persons who had a negative molecular test, according to gender, age and date of molecular ascertainment. We used a conditional logistic regression for estimating relative risk reduction of either variants associated with natural and/or induced immunization and corresponding 95% confidence interval (CI). RESULTS: Previous infection was associated with 91% (95% CI 85% to 95%) reduced relative risk of reinfection, without evidence of significant differences between delta and alpha cases (p=0.547). Significant lower vaccinal protection against delta than alpha variant infection was observed with reduced relative risk associated with partial vaccination respectively of 29% (7% to 45%), and 62% (48% to 71%) (p=0.001), and with complete vaccination respectively of 75% (66% to 82%) and 90% (85% to 94%) (p=0.003). CONCLUSIONS: Lower protection towards infections caused by the delta variant with respect to alpha variant was noticed, even after the completion of the vaccination cycle. This finding would support efforts to maximize both vaccine uptake with two doses and fulfilment with individual protection measures, especially as the delta variant is rampant worldwide presently.

Medical occurrence and safety of SARS-CoV-2 vaccination outside of the hospital setting.

During COVID-19 pandemic, vaccination has been strongly recommended and advocated to prevent COVID-19 infection and adverse outcomes, particularly among at-risk populations. The vaccination against SARS-CoV-2 (COVAC) occurred at off-site locations capable of accommodating large crowds, distinct from the hospital setting, where a team of intensivists, emergency physicians, and nurses, ensuring prompt medical attention (medical occurrences, MO) in cases of adverse event following immunization. Our aims were to estimate the incidence of MO, and to assess its association with demographics, and vaccine characteristics. Our retrospective cohort study included all subject aged 12 years and older who received vaccinations at two large out-of-hospital vaccination hubs (Fiera Milano City, Palazzo delle Scintille), between April 12th and August 31st, 2021. Nine hundred and ninety-five thousand and twenty-eight vaccinations were administrated. MOs incidence rate was 278/100,000 doses (95% confidence interval (CI) 268-289). Most MOs were mild (86.27%) and mainly observed in subjects who received the Comirnaty vaccine; 92 MOs (3.32%) were severe and mostly occurred in recipients of the Vaxzeria vaccine. The incidence rate for hospital transfers following vaccination was 4.7/100,000 doses (95% CI 3.5-6.2) and any level of anaphylaxis occurred in 0.4 cases per 100,000 administrated doses (95% CI 0.3.-0.7). Sex, age, type of vaccine and first dose were associated with incidence of MO. Our results showed a low incidence rate in MOs after COVAC, mainly mild and support the feasibility, effectiveness and safety of vaccinations administered in hubs with a dedicated SEU located outside of the hospital setting.

Vaccinome landscape in nearly 620,000 patients with diabetes.

INTRODUCTION: Type 1 (T1D) and type 2 diabetes (T2D) are associated with an elevated incidence of infectious diseases and a higher risk of infections-related hospitalization and death. In this study, we delineated the "vaccinome" landscape obtained with a large immunization schedule offered by the Regional Government of Lombardy in a cohort of 618,396 patients with diabetes (T1D and T2D). METHODS: Between September 2021 and September 2022, immunization coverage for influenza, meningococcus, pneumococcus, and herpes zoster was obtained from the public computerized registry of the healthcare system of Lombardy Region (Italy) in 618,396 patients with diabetes and in 9,534,087 subjects without diabetes. Type of diabetes, age, mortality, and hospitalizations were retrospectively analyzed in vaccinated and unvaccinated patients. RESULTS: Among patients with diabetes (T1D and T2D), 44.6% received the influenza vaccine, 10.9% the pneumococcal vaccine, 2.5% the anti-meningococcus vaccine and 0.7% the anti-zoster vaccine. Patients with diabetes immunized for influenza, zoster and meningococcus showed a 2-fold overall reduction in mortality risk and a decrease in hospitalizations. A 3-fold lower risk of mortality and a decrease in hospitalizations for both cardiac and pulmonary causes were also observed after influenza, zoster, and meningococcus immunization in older patients with diabetes. CONCLUSIONS: Immunization coverage is still far from the recommended targets in patients with diabetes. Despite this, influenza vaccination protected nearly 3,800 per 100,000 patients with diabetes from risk of death. The overall impressive decrease in mortality and hospitalizations observed in vaccinated patients strengthens the need for scaling up the "vaccinome" landscape in patients with diabetes.

Tuberculosis outbreak in a primary school, Milan, Italy.

Investigation of an outbreak of tuberculosis (TB) in a primary school in Milan, Italy, found 15 schoolchildren had active TB disease and 173 had latent TB infection. TB was also identified in 2 homeless men near the school. Diagnostic delay, particularly in the index case-patient, contributed to the transmission of infection.

SARS-CoV-2 Vaccine Uptake during Pregnancy in Regione Lombardia, Italy: A Population-Based Study of 122,942 Pregnant Women.

Italy has been one of the hardest hit countries in the European Union since the beginning of the SARS-CoV-2 pandemic, and Regione Lombardia (RL) has reported the largest number of cases in the country. This population-based retrospective study analyzed RL records of 122,942 pregnant women to describe SARS-CoV-2 vaccination uptake in the pregnant population, to compare pregnant women vaccine uptake vs. women of childbearing age and to evaluate the impact of vaccination status in pregnant women on admissions to intensive care units during 2021. Vaccination uptake according to citizenship and educational level and the comparison between pregnant and non-pregnant women was performed by Z test. A logistic regression was performed to compare age groups. Out of 122,942 pregnant women, 79.9% were vaccinated at the end of 2021. The vaccine uptake rate was significantly lower in pregnant versus non-pregnant women but increased after the issuing of official recommendations. Vaccine administration was significantly higher among pregnant women with Italian citizenship and with a high level of education in all trimesters. In conclusion, the role of official recommendations with explicit communication about the importance and safety of vaccination in pregnancy is critical to obtain trust and acceptance among pregnant women.

Persistence of protection against SARS-CoV-2 clinical outcomes up to 9 months since vaccine completion: a retrospective observational analysis in Lombardy, Italy.

BACKGROUND: Scarce information is available on the duration of the protective effect of COVID-19 vaccination against the risk of SARS-CoV-2 infection and its severe clinical consequences. We investigated the effect of time since vaccine completion on the SARS-CoV-2 infection and its severe forms. METHODS: In this retrospective observational analysis using the vaccination campaign integrated platform of the Italian region of Lombardy, 5 351 085 individuals aged 12 years or older who received complete vaccination from Jan 17 to July 31, 2021, were followed up from 14 days after vaccine completion until Oct 20, 2021. Changes over time in outcome rates (ie, SARS-CoV-2 infection and severe illness among vaccinated individuals) were analysed with age-period-cohort models. Trends in vaccine effectiveness (ie, outcomes comparison in vaccinated and unvaccinated individuals) were also measured. FINDINGS: Overall, 14 140 infections and 2450 severe illnesses were documented, corresponding to incidence rates of 6·7 (95% CI 6·6-6·8) and 1·2 (1·1-1·2) cases per 10 000 person-months, respectively. From the first to the ninth month since vaccine completion, rates increased from 4·6 to 10·2 infections, and from 1·0 to 1·7 severe illnesses every 10 000 person-months. These figures correspond to relative reduction of vaccine effectiveness of 54·9% (95% CI 48·3-60·6) for infection and of 40·0% (16·2-57·0) for severe illness. The increasing infection rate was greater for individuals aged 60 years or older who received adenovirus-vectored vaccines (from 4·0 to 23·5 cases every 10 000 person-months). The increasing severe illness rates were similar for individuals receiving mRNA-based vaccines (from 1·1 to 1·5 every 10 000 person-months) and adenovirus-vectored vaccines (from 0·5 to 0·9 every 10 000 person-months). INTERPRETATION: Although the risk of infection after vaccination, and even more of severe illness, remains low, the gradual increase in clinical outcomes related to SARS-CoV-2 infection suggests that the booster campaign should be accelerated and that social and individual protection measures against COVID-19 spread should not be abandoned. FUNDING: None.

Vulnerability Predictors of Post-Vaccine SARS-CoV-2 Infection and Disease-Empirical Evidence from a Large Population-Based Italian Platform.

We aimed to identify individual features associated with increased risk of post-vaccine SARS-CoV-2 infection and severe COVID-19 illness. We performed a nested case-control study based on 5,350,295 citizens from Lombardy, Italy, aged ≥ 12 years who received a complete anti-COVID-19 vaccination from 17 January 2021 to 31 July 2021, and followed from 14 days after vaccine completion to 11 November 2021. Overall, 17,996 infections and 3023 severe illness cases occurred. For each case, controls were 1:1 (infection cases) or 1:10 (severe illness cases) matched for municipality of residence and date of vaccination completion. The association between selected predictors (sex, age, previous occurrence of SARS-CoV-2 infection, type of vaccine received, number of previous contacts with the Regional Health Service (RHS), and the presence of 59 diseases) and outcomes was assessed by using multivariable conditional logistic regression models. Sex, age, previous SARS-CoV-2 infection, type of vaccine and number of contacts with the RHS were associated with the risk of infection and severe illness. Moreover, higher odds of infection and severe illness were significantly associated with 14 and 34 diseases, respectively, among those investigated. These results can be helpful to clinicians and policy makers for prioritizing interventions.

Balancing Benefits and Harms of COVID-19 Vaccines: Lessons from the Ongoing Mass Vaccination Campaign in Lombardy, Italy.

Background. Limited evidence exists on the balance between the benefits and harms of the COVID-19 vaccines. The aim of this study is to compare the benefits and safety of mRNA-based (Pfizer-BioNTech and Moderna) and adenovirus-vectored (Oxford-AstraZeneca) vaccines in subpopulations defined by age and sex. Methods. All citizens who are newly vaccinated from 27 December 2020 to 3 May 2021 are matched to unvaccinated controls according to age, sex, and vaccination date. Study outcomes include the events that are expected to be avoided by vaccination (i.e., hospitalization and death from COVID-19) and those that might be increased after vaccine inoculation (i.e., venous thromboembolism). The incidence rate ratios (IRR) of vaccinated and unvaccinated citizens are separately estimated within strata of sex, age category and vaccine type. When suitable, number needed to treat (NNT) and number needed to harm (NNH) are calculated to evaluate the balance between the benefits and harm of vaccines within each sex and age category. Results. In total, 2,351,883 citizens are included because they received at least one dose of vaccine (755,557 Oxford-AstraZeneca and 1,596,326 Pfizer/Moderna). A reduced incidence of COVID-19-related outcomes is observed with a lowered incidence rate ranging from 55% to 89% and NNT values ranging from 296 to 3977. Evidence of an augmented incidence of harm-related outcomes is observed only for women aged <50 years within 28 days after Oxford-AstraZeneca (being the corresponding adjusted IRR of 2.4, 95% CI 1.1−5.6, and NNH value of 23,207, 95% CI 10,274−89,707). Conclusions. A favourable balance between benefits and harms is observed in the current study, even among younger women who received Oxford-AstraZeneca.