Sequence analysis of respiratory syncytial virus cases reveals a novel subgroup -B strain circulating in north-central Italy after pandemic restrictions.

BACKGROUND: Following the pandemic restrictions, the epidemiology of respiratory syncytial virus (RSV) has changed, leading to intense hospitalization peaks. OBJECTIVES: This study, conducted at multiple sites in Italy, aimed to describe the temporal dynamics of two post-COVID-19 RSV epidemics. Additionally, the circulating RSV-A and -B lineages were characterized and compared to those found in 2018 and 2019. STUDY DESIGN: Respiratory specimens and data were collected from RSV-positive patients, both inpatients, and outpatients, of all ages at three sites in north-central Italy. To analyze these samples, roughly one-sixth were sequenced in the attachment glycoprotein G gene and subjected to phylogenetic and mutational analyses, including pre-pandemic sequences from north-central Italy. RESULTS: The first post-pandemic surge of RSV cases was quite intense, occurring from October 2021 to early January 2022. The subsequent RSV epidemic (from November 2022 to early March 2023) also had a high impact, characterized by a rise in elderly patient cases. Post-pandemic cases of RSV-A were caused by various strains present in Italy prior to COVID-19. In contrast, a distinct RSV-B lineage, which was concurrently spreading in other countries, was identified as the main cause of the surge in 2022-2023 but remained undetected in Italy before the pandemic. CONCLUSIONS: This study describes the temporal dynamics of post-pandemic RSV subgroups and uncovers a lineage of RSV-B with high genetic divergence that may have increased the impact of decreased population immunity.

[Analysis of predictive factors for non-adherence to organized screening for colorectal and breast cancers in the pre-pandemic period (2018-2019) in Lombardy Region (Northern Italy)]. / Analisi dei fattori predittivi della mancata adesione allo screening organizzato per i tumori del colon retto e della mammella nel periodo pre-pandemico (2018-2019) in Lombardia.

BACKGROUND: according to the International Agency for Cancer Research on Cancer, in 2022, breast cancer is the most common cancer in the Italian population, followed by colorectal cancer. Oncological screenings represent an effective secondary prevention strategy to counteract colorectal and breast cancers, significantly reducing mortality. In Lombardy Region (Northern Italy), screening programmes have been active since 2007, but adherence, especially in specific population subgroups, remains lower than expected. OBJECTIVES: to analyse potential predictors of non-adherence to colorectal and breast cancer screening in the Lombardy Region during the pre-pandemic period of 2018-2019. DESIGN: a retrospective cohort study aimed at investigating the role of sociodemographic variables, health status, and access to the healthcare system on non-adherence to colorectal and breast cancer screening. Statistical analyses were conducted separately by each Agency for Health Protection (ATS). The results of the models were synthesized across the Lombardy region through random-effects meta-analysis. SETTING AND PARTICIPANTS: residents within the territory of each ATS in Lombardy as of 01.01.2018 and aged between 49 and 69 years at the beginning of the follow-up. MAIN OUTCOMES MEASURES: adherence to colorectal and breast cancer screenings. RESULTS: during the study period, across the Lombardy Region, 2,820,138 individuals were eligible to participate in colorectal cancer screening, and 1,357,344 women were eligible to participate in breast cancer screening, with an invitation coverage of 87% and 86%, respectively.For breast cancer screening, older age, cardiopathy, chronic obstructive pulmonary disease (COPD), inflammatory bowel diseases (IBD), autoimmune diseases, and presence of a rare disease are associated with a reduced risk of non-adherence. Conversely, foreign citizenship, oncological diagnosis, transplant, chronic kidney disease/dialysis, diabetes, heart failure, arterial or cerebral vasculopathy, and presence of a neurological diagnosis are associated with significant excess risks of non-participation. For colorectal cancer screening, factors favouring adherence include female gender, older age, cardiopathy, COPD, autoimmune diseases, and having access/utilization of primary care. Non-adherence is associated with foreign citizenship, transplant, chronic kidney disease/dialysis, diabetes, heart failure, arterial or cerebral vasculopathy, IBD, neurological diseases, residence in assisted living facilities, use of integrated home care, and presence of disability. CONCLUSIONS: this is the first study conducted in the Lombardy Region which explores the theme of equity of access to organized screenings. This analysis highlights how sociodemographic determinants, chronic conditions, and access to the healthcare and social healthcare system constitute significant risk factors for non-adherence to screening programmes. Based on the results of this analysis, communication and/or organizational change interventions will be developed to counteract inequalities in access to effective prevention procedures.

Increased reports of measles in the Metropolitan City of Milan, northern Italy, September 2023 to March 2024.

Since late 2023, the Metropolitan City of Milan and surrounding areas (northern Italy) have been experiencing a resurgence of measles, with most cases detected starting from January 2024. During this brief period, we observed measles in travellers from endemic areas, participants in international events, vaccinees and healthcare workers. Indigenous cases have also been identified. Even though we have not yet identified large and disruptive outbreaks, strengthening surveillance and vaccination activities is pivotal to help limit the impact of measles spread.

Estimating All-Cause Deaths Averted in the First Two Years of the COVID-19 Vaccination Campaign in Italy.

Comparing deaths averted by vaccination campaigns is a crucial public health endeavour. Excess all-cause deaths better reflect the impact of the pandemic than COVID-19 deaths. We used a seasonal autoregressive integrated moving average with exogenous factors model to regress daily all-cause deaths on annual trend, seasonality, and environmental temperature in three Italian regions (Lombardy, Marche and Sicily) from 2015 to 2019. The model was used to forecast excess deaths during the vaccinal period (December 2020-October 2022). We used the prevented fraction to estimate excess deaths observed during the vaccinal campaigns, those which would have occurred without vaccination, and those averted by the campaigns. At the end of the vaccinal period, the Lombardy region proceeded with a more intensive COVID-19 vaccination campaign than other regions (on average, 1.82 doses per resident, versus 1.67 and 1.56 in Marche and Sicily, respectively). A higher prevented fraction of all-cause deaths was consistently found in Lombardy (65% avoided deaths, as opposed to 60% and 58% in Marche and Sicily). Nevertheless, because of a lower excess mortality rate found in Lombardy compared to Marche and Sicily (12, 24 and 23 per 10,000 person-years, respectively), a lower rate of averted deaths was observed (22 avoided deaths per 10,000 person-years, versus 36 and 32 in Marche and Sicily). In Lombardy, early and full implementation of adult COVID-19 vaccination was associated with the largest reduction in all-cause deaths compared to Marche and Sicily.

Dynamics of viral DNA shedding and culture viral DNA positivity in different clinical samples collected during the 2022 mpox outbreak in Lombardy, Italy.

BACKGROUND: Mpox virus (MPXV) has recently spread outside of sub-Saharan Africa. This large multicentre study was conducted in Lombardy, the most densely populated Italian region accounting for more than 40% of Italian cases. The present study aims to: i) evaluate the presence and the shedding duration of MPXV DNA in different body compartments correlating the MPXV viability with the time to onset of symptoms; ii) provide evidence of MPXV persistence in different body compartment as a source of infection and iii) characterize the MPXV evolution by whole genome sequencing (WGS) during the outbreak occurred in Italy. MATERIAL AND METHODS: The study included 353 patients with a laboratory-confirmed diagnosis of MPXV infection screened in several clinical specimens in the period May 24th - September 1st, 2022. Viral isolation was attempted from different biological matrices and complete genome sequencing was performed for 61 MPXV strains. RESULTS: MPXV DNA detection was more frequent in the skin (94.4%) with the longest median time of viral clearance (16 days). The actively-replicating virus in cell culture was obtained for 123/377 (32.6%) samples with a significant higher viral quantity on isolation positive samples (20 vs 31, p < 0.001). The phylogenetic analysis highlighted the high genetic identity of the MPXV strains collected, both globally and within the Lombardy region. CONCLUSION: Skin lesion is gold standard material and the high viral load and the actively-replicating virus observed in genital sites confirms that sexual contact plays a key role in the viral transmission.

Increased circulation of echovirus 11 in the general population and hospital patients as elicited by the non-polio enterovirus laboratory-based sentinel surveillance in northern Italy, 2023.

OBJECTIVES: Following the alert of echovirus 11 (E-11) infection in neonates in EU/EEA Member States, we conducted an investigation of E-11 circulation by gathering data from community and hospital surveillance of enterovirus (EV) in northern Italy from 01 August 2021 to 30 June 2023. METHODS: Virological results of EVs were obtained from the regional sentinel surveillance database for influenza-like illness (ILI) in outpatients, and from the laboratory database of ten hospitals for inpatients with either respiratory or neurological symptoms. Molecular characterization of EVs was performed by sequence analysis of the VP1 gene. RESULTS: In our ILI series, the rate of EV-positive specimens showed an upward trend from the end of May 2023, culminating at the end of June, coinciding with an increase in EV-positive hospital cases. The E-11 identified belonged to the D5 genogroup and the majority (83%) were closely associated with the novel E-11 variant, first identified in severe neonatal infections in France since 2022. E-11 was identified sporadically in community cases until February 2023, when it was also found in hospitalized cases with a range of clinical manifestations. All E-11 cases were children, with 14 out of 24 cases identified through hospital surveillance. Of these cases, 60% were neonates, and 71% had severe clinical manifestations. CONCLUSION: Baseline epidemiological data collected since 2021 through EV laboratory-based surveillance have rapidly tracked the E-11 variant since November 2022, alongside its transmission during the late spring of 2023.

How a laboratory-based antimicrobial resistance (AMR) regional surveillance system can address large-scale and local AMR epidemiology: the MICRO-BIO experience.

Antimicrobial resistance is a significant threat to public health, with Italy experiencing substantial challenges in terms of AMR rate, surveillance system and activities to combat AMR. In response, the MICRO-BIO project was initiated as part of the National Plan to Combat Antibiotic Resistance by Region Lombardy health department. It was launched in 2018 with the aim of creating a surveillance tool by integrating data on bacterial isolates from microbiology laboratories. The participating laboratories were directly involved in reviewing and addressing discrepancies in the transmission data quality assessment. Despite the disruptions caused by COVID-19, 30 out of 33 laboratories in the Lombardy Region were successfully integrated by October 2023, with 1,201,000 microbiological data collected in the first nine months of 2023. In 2022 the analysis yielded 15,037 blood culture results from 20 labs passing validation. Data regarding the antimicrobial resistance profile of high-priority pathogens was analyzed at regional and single-hospital levels. The MICRO-BIO project represents a significant step toward strengthening AMR surveillance in a highly populated region. As a multi-disciplinary tool encompassing the fields of public health and IT (information technology), this tool has the potential to inform regional and local AMR epidemiology.

The contribution of the private healthcare sector during the COVID-19 pandemic: the experience of the Lombardy Region in Northern Italy.

Introduction: In Lombardy, the first European region hit by the COVID-19 pandemic, for decades the regional public healthcare service has followed a mixed delivery model with extensive involvement of private accredited providers. The study aimed at examining the role of the private sector in delivering healthcare services (diagnosis, hospitalization, and vaccination) during the pandemic. Study design: Healthcare system study. Methods: We analysed regional healthcare data referring to the period from March 2020 onwards to assess the availability of acute care and intensive care hospital beds, SARS-CoV-2 tests, and COVID-19 vaccinations. We specifically examined healthcare offered by private accredited providers within the region. Results: Of the 12,306 converted beds for COVID-19 treatment, 4,975 (40%) were in accredited private hospitals. Intensive care beds increased by 95%, reaching 1,755, with 484 (28%) in accredited private hospitals. Since the pandemic onset, 28.9 million (62%) of SARS-CoV-2 tests were conducted by private accredited facilities including pharmacies. Private sector actively contributed to the COVID-19 vaccination campaign administering over 2.6 million doses in 2021, enhancing vaccination capacity to its peak. Conclusions: The longstanding relationship between the public and private sectors within the Lombardy regional healthcare service facilitated a rapid increase in hospital bed capacity, the upscaling of SARS-CoV-2 testing capacity, and the achievement of vaccination goals to address the COVID-19 emergency. Therefore, alongside a robust and adequately funded public healthcare service, the private sector serves as an asset to enhance the resilience of healthcare systems, in line with WHO indications.

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.

Impact of the educational program "Igiene Insieme"in 1,991 Italian primary schools: student behavior and incidence of SARS-CoV-2.

OBJECTIVE: To evaluate the impact of the health educational program "Igiene Insieme 2021/2022" on Italian primary school children's knowledge, attitudes and practice of hygiene and sanitation and to compare incidence of SARS-CoV-2 in schools participating the project with regional data of Lombardy and Apulia. METHODS: Participating schools were provided with a hygiene kit containing educational material for teachers and sanitizing products for students. We conducted a pre-post evaluation administering a questionnaire before and after the intervention. In addition, we compared SARS-CoV-2 incidence of the participating primary schools (225 in Lombardy and 120 in Apulia) to regional-level data. We tested the differences between groups by using the Chi-squared test. RESULTS: Of 1,991 schools, 472 responded to both questionnaires for a total of 16,988 students. 17.3% of the students learned the importance of handwashing in preventing infections, 22.6% when to wash hands, 18.5% the existence of alternative solutions in absence of soap and water, 23.2% how to correctly wash hands. A lower incidence of SARS-CoV-2 infections was recorded in primary schools participating in the project as compared to the average regional incidence in Lombardy (9.6% vs.14.8%) and Apulia (10.7% vs.12.0%) for the same age group. CONCLUSIONS: We report an overall positive effect of health education interventions in primary schools. Although the limitations in the study design, our findings are important to inform planning, implementation and monitoring of health promotion campaigns in young generations so as to contribute to limit the risk of infection spread at the community level.

A territory-wide opportunistic, hospital-based HCV screening in the general population from northern Italy: The 1969-1989 birth-cohort.

BACKGROUND AND AIM: The World Health Organization (WHO) goal of Hepatitis C Virus (HCV) elimination by 2030 rose awareness about the need of screening plans, worldwide. In Italy, graduated screening starting from people born in 1969-1989 might be the most-effective strategy. We performed an opportunistic HCV screening study in the general population attending health facilities in Lombardy region, Northern Italy. METHODS: This is a prospective, multicenter, territory-wide, opportunistic study supported by the Regional Government of Lombardy, Italy. Between June 2022 and December 2022, all subjects born in 1969-1989, hospitalized or accessing blood collection centres were offered anti-HCV and HCV-RNA tests. Patients with known anti-HCV positivity and/or previous anti-HCV treatment were excluded. Demographic features were uploaded into a regional web-based platform. RESULTS: In total, 120 193 individuals were screened in 75 centres. Mean age was 44 (±6) years, 65.2% were females, 83.7% were tested at blood collection centres. Anti-HCV tested positive in 604 (0.50%) subjects: mean age 47 (±5), 51.1% females. HCV seroprevalence was higher in males (p < 0.00001), elderly (p < 0.00001) and in- vs. outpatients (p = 0.0009). HCV-RNA was detectable in 125 out of 441 (28.3%) anti-HCV positive subjects. Actively infected patients were 46 (±6) years old, mainly males (56.8%). The overall prevalence of active HCV infection was 0.10%, higher in elderly (p = 0.0003) and in in-patients (p = 0.0007). Among 93 HCV-RNA positive patients, the median age was 48 years, 58% males, 62% Italian born, median HCV-RNA levels were 6,1 log IU/mL, liver stiffness measurement (LSM) values 5.5 (3.1-29.9) kPa and ALT levels 48 U/L. CONCLUSIONS: The prevalence of active HCV infection in the 1969-1989 population attending health facilities in Lombardy was low. Most viremic patients were Italian-born, with mild liver disease but high-HCV-RNA levels. Due to the higher prevalence in the elderly, the extension of such opportunistic screening programs to lower birth cohorts would be warranted.

Preliminary results on an autochthonous dengue outbreak in Lombardy Region, Italy, August 2023.

In August 2023, six locally acquired dengue virus 1 infections were detected in Lodi province, Lombardy Region, in northern Italy, where the vector Aedes albopictus is present. Four cases were hospitalised, none died. The viruses clustered with Peruvian and Brazilian strains collected between 2021 and 2023. This preliminary report highlights the importance of continued integrated surveillance of imported vector-borne virus infections and the potential for tropical disease outbreaks in highly populated regions of northern Italy where competent vectors are present.

Reconstructing the impact of COVID-19 on the immunity gap and transmission of respiratory syncytial virus in Lombardy, Italy.

BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of hospitalisation and mortality in young children globally. The social distancing measures implemented against COVID-19 in Lombardy (Italy) disrupted the typically seasonal RSV circulation during 2019-2021 and caused substantially more hospitalisations during 2021-2022. The primary aim of this study is to quantify the immunity gap-defined as the increased proportion of the population naïve to RSV infection following the relaxation of COVID-19 restrictions in Lombardy, which has been hypothesised to be a potential cause of the increased RSV burden in 2021-2022. METHODS: We developed a catalytic model to reconstruct changes in the age-dependent susceptibility profile of the Lombardy population throughout the COVID-19 pandemic. The model is calibrated to routinely collected hospitalisation, syndromic, and virological surveillance data and tested for alternative assumptions on age-dependencies in the risk of RSV infection throughout the pandemic. FINDINGS: We estimate that the proportion of the Lombardy population naïve to RSV infection increased by 60.8% (95% CrI: 55.2-65.4%) during the COVID-19 pandemic: from 1.4% (95% CrI: 1.3-1.6%) in 2018-2019 to 2.3% (95% CrI: 2.2-2.5%) before the 2021-2022 season, corresponding to an immunity gap of 0.87% (95% CrI: 0.87-0.88%). We found evidence of heterogeneity in RSV transmission by age, suggesting that the COVID-19 restrictions had variable impact on the contact patterns and risk of RSV infection across ages. INTERPRETATION: We estimate a substantial increase in the population-level susceptibility to RSV in Lombardy during 2019-2021, which contributed to an increase in primary RSV infections in 2021-2022. FUNDING: UK Medical Research Council (MRC), UK Foreign, Commonwealth & Development Office (FCDO), EDCTP2 programme, European Union, Wellcome Trust, Royal Society, EU-MUR PNRR INF-ACT.

Wastewater-based epidemiology revealed in advance the increase of enterovirus circulation during the Covid-19 pandemic.

Wastewater-based epidemiology (WBE) was conducted to track Enteroviruses (EVs) circulation in the Milan metropolitan area (Northern Italy) during Covid-19 pandemic (March 2020-December 2022). 202 composite 24-hour wastewater samples (WWSs) were collected weekly from March 24, 2020, to December 29, 2022 at the inlet of two wastewater treatment plants (WWTP) in Milan (1.5 million inhabitants). EV-RNA was quantified and molecular characterization of non-polio EVs (NPEV) was performed by Sanger sequence analysis. Data from WWS were matched with virological data collected in the framework of Influenza-Like Illness (ILI) surveillance in the same place and time. EV-RNA was identified in 88.2 % of WWSs. The peak in EVs circulation was observed in late August 2020 (upon conclusion of the first national lockdown), in late August 2021, and in mid-April 2022. EV-RNA concentration in WWS (normalized as copies/d/1000 people) at peak of circulation presented a yearly increase (2020: 2.47 × 1010; 2021: 6.81 × 1010; 2022: 2.14 × 1011). This trend overlapped with trend in EV-positivity rate in ILI cases, expanded from 21.7 % in 2021 to 55.6 % in 2022. EV trends in WWS preceded clinical sample detections in 2021 and 2022 by eight and five weeks, respectively, acting as an early warning of outbreak. Although sequencing of EV-positive WWSs revealed the presence of multiple EV strains, typing remained inconclusive. Molecular characterization of EVs in clinical samples revealed the co-circulation of several genotypes: EV-A accounted for 60 % of EVs, EV-B for 16.7 %, EV-D68 for 23.3 %. EVs were circulating in Milan metropolitan area between March 2020 and December 2022. The epidemiological trends unfolded the progressive accumulation of EV transmission in the population after removal of Covid-19 restrictions. The increased circulation of EVs in 2021-2022 was identified at least 35 days in advance compared to the analysis of clinical data. The inconclusive results of Sanger sequencing lookout for improvement and innovative molecular approaches to deepen track EVs.

Population-level benefits of increasing influenza vaccination uptake among Italian older adults: results from a granular panel model.

Background: The impact of seasonal influenza vaccination (SIV) on mortality is still controversial; some studies have claimed that increasing vaccination coverage rates is beneficial, while others have found no significant association. This study aimed to construct a granular longitudinal dataset of local VCRs and assess their effect on pneumonia- and influenza-related (P&I) mortality among Italian adults aged ≥ 65 years. Methods: NUTS-3 (nomenclature of territorial units for statistics) level data on SIV coverage were collected via a survey of local data holders. Fixed- and random-effects panel regression modeling, when adjusted for potential confounders, was performed to assess the association between local SIV coverage rates and P&I mortality in older adults. Results: A total of 1,144 local VCRs from 2003 to 2019 were ascertained. In the fully adjusted fixed-effects model, each 1% increase in vaccination coverage was associated (P < 0.001) with a 0.6% (95% CI: 0.3-0.9%) average over-time decrease in P&I mortality. With an annual average of 9,293 P&I deaths in Italy, this model suggested that 56 deaths could have been avoided each year by increasing SIV coverage by 1%. The random-effects model produced similar results. The base-case results were robust in a sensitivity analysis. Conclusion: Over the last two decades, Italian jurisdictions with higher SIV uptake had, on average, fewer P&I deaths among older adults. Local policy-makers should implement effective strategies to increase SIV coverage in the Italian senior population.

Asymptomatic infection with clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) in carnivore pets, Italy, April 2023.

In April 2023, an outbreak of clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) viruses carrying the T271A mammalian adaptive mutation in the PB2 protein was detected in a backyard poultry farm in Italy. Five domestic dogs and one cat living on the premises had seroconverted in the absence of clinical signs. Virological and serological monitoring of individuals exposed to the virus proved the absence of human transmission, however, asymptomatic influenza A(H5N1) infections in mammalian pets may have important public health implications.

Listeria monocytogenes Transmission from Donated Blood to Platelet Transfusion Recipient, Italy.

We report Listeria monocytogenes infection in a patient in Italy who was transfused with pooled platelet concentrate. Genomic analysis revealed that L. monocytogenes isolates from the donor blood unit, the transfused platelets, and the patient's blood culture were genetically closely related, confirming transfusion transmission. Additional surveillance and secondary bacterial screening could improve transfusion safety.

Web-based surveillance of respiratory infection outbreaks: retrospective analysis of Italian COVID-19 epidemic waves using Google Trends.

Introduction: Large-scale diagnostic testing has been proven insufficient to promptly monitor the spread of the Coronavirus disease 2019. Electronic resources may provide better insight into the early detection of epidemics. We aimed to retrospectively explore whether the Google search volume has been useful in detecting Severe Acute Respiratory Syndrome Coronavirus outbreaks early compared to the swab-based surveillance system. Methods: The Google Trends website was used by applying the research to three Italian regions (Lombardy, Marche, and Sicily), covering 16 million Italian citizens. An autoregressive-moving-average model was fitted, and residual charts were plotted to detect outliers in weekly searches of five keywords. Signals that occurred during periods labelled as free from epidemics were used to measure Positive Predictive Values and False Negative Rates in anticipating the epidemic wave occurrence. Results: Signals from "fever," "cough," and "sore throat" showed better performance than those from "loss of smell" and "loss of taste." More than 80% of true epidemic waves were detected early by the occurrence of at least an outlier signal in Lombardy, although this implies a 20% false alarm signals. Performance was poorer for Sicily and Marche. Conclusion: Monitoring the volume of Google searches can be a valuable tool for early detection of respiratory infectious disease outbreaks, particularly in areas with high access to home internet. The inclusion of web-based syndromic keywords is promising as it could facilitate the containment of COVID-19 and perhaps other unknown infectious diseases in the future.

Natural and vaccine-induced immunity are equivalent for the protection against SARS-CoV-2 infection.

OBJECTIVES: To compare the long-term cumulative risk of SARS-CoV-2 infection associated with natural and vaccine-induced immunity. METHODS: Retrospective population-based cohort study based on registry of COVID-19 vaccinations and SARS-CoV-2 infections among 9.1 million citizens of Lombardy, Italy, eligible for vaccination on 27th December 2020. Those who developed SARS-CoV-2 infection from 24th May to 14th September 2021, provided they did not yet receive the COVID-19 vaccine when infection was confirmed, and those who received the second mRNA vaccine dose, provided they had not yet developed the infection, were selected to be 1:1 matched for sex, age and index date. The latter corresponded to 90 days after confirmed infection or 14 days after vaccine administration. A control cohort including citizens who, on the index date, had neither developed infection nor received vaccination was also selected. Kaplan-Meier curves were used for comparing the cumulative incidence of new SARS-CoV-2 infection from the index date until 22nd June 2022. RESULTS: Overall, 19,418 1:1:1 risk-sets were included. After 9 months of follow-up, the cumulative risk of new SARS-CoV-2 infection was 21.8%, 22.0%, and 25.9%, respectively, among exposed to natural immunity, vaccine-induced immunity and unexposed. CONCLUSIONS: Equivalent potential for protecting against new SARS-CoV-2 infection was observed.