Effectiveness of BNT162b2 vaccine against SARS-CoV-2 infection and severe COVID-19 in children aged 5-11 years in Italy: a retrospective analysis of January-April, 2022.

BACKGROUND: By April 13, 2022, more than 4 months after the approval of BNT162b2 (Pfizer-BioNTech) for children, less than 40% of 5-11-year-olds in Italy had been vaccinated against COVID-19. Estimating how effective vaccination is in 5-11-year-olds in the current epidemiological context dominated by the omicron variant (B.1.1.529) is important to inform public health bodies in defining vaccination policies and strategies. METHODS: In this retrospective population analysis, we assessed vaccine effectiveness against SARS-CoV-2 infection and severe COVID-19, defined as an infection leading to hospitalisation or death, by linking the national COVID-19 surveillance system and the national vaccination registry. All Italian children aged 5-11 years without a previous diagnosis of infection were eligible for inclusion and were followed up from Jan 17 to April 13, 2022. All children with inconsistent vaccination data, diagnosed with SARS-CoV-2 infection before the start date of the study or without information on the municipality of residence were excluded from the analysis. With unvaccinated children as the reference group, we estimated vaccine effectiveness in those who were partly vaccinated (one dose) and those who were fully vaccinated (two doses). FINDINGS: By April 13, 2022, 1 063 035 (35·8%) of the 2 965 918 children aged 5-11 years included in the study had received two doses of the vaccine, 134 386 (4·5%) children had received one dose only, and 1 768 497 (59·6%) were unvaccinated. During the study period, 766 756 cases of SARS-CoV-2 infection and 644 cases of severe COVID-19 (627 hospitalisations, 15 admissions to intensive care units, and two deaths) were notified. Overall, vaccine effectiveness in the fully vaccinated group was 29·4% (95% CI 28·5-30·2) against SARS-CoV-2 infection and 41·1% (22·2-55·4) against severe COVID-19, whereas vaccine effectiveness in the partly vaccinated group was 27·4% (26·4-28·4) against SARS-CoV-2 infection and 38·1% (20·9-51·5) against severe COVID-19. Vaccine effectiveness against infection peaked at 38·7% (37·7-39·7) at 0-14 days after full vaccination and decreased to 21·2% (19·7-22·7) at 43-84 days after full vaccination. INTERPRETATION: Vaccination against COVID-19 in children aged 5-11 years in Italy showed a lower effectiveness in preventing SARS-CoV-2 infection and severe COVID-19 than in individuals aged 12 years and older. Effectiveness against infection appears to decrease after completion of the current primary vaccination cycle. FUNDING: None. TRANSLATION: For the Italian translation of the summary see Supplementary Materials section.

Role of the National Immunisation Technical Advisory Groups in 13 European countries in the decision-making process on vaccine recommendations.

In Europe, National Immunisation Technical Advisory Groups (NITAGs) were established in most countries to promote evidence-informed decision-making in introducing new or improved vaccines or changing recommendations for existing ones. Still, the role, activities and outcomes of NITAGs have not been optimally implemented across Europe. Within the European Joint Action on Vaccination (EU-JAV), we conducted a survey to collect information on decision-making process including the main criteria for the introduction of new vaccines or changes to recommendations on their use. Between December 2021 and January 2022, 13 of the 28 European countries invited participated in an online survey. The criteria ranked as most relevant were disease burden and availability of financial resources. Only one country specified that the NITAG recommendations were binding for the government or the health authority. Vaccinations more often reported for introduction or recommendation changes were those against herpes zoster, influenza, human papillomavirus infection, pneumococcal and meningococcal disease. The planned changes will mainly address children and adolescents (2-18 years) and adults (≥ 45-65 years). Our findings show potential overlaps in the activities of NITAGs between countries; and therefore, collaboration between NITAGs may lead to optimisation of the workload and better use of resources.

Relative effectiveness of bivalent Original/Omicron BA.4-5 mRNA vaccine in preventing severe COVID-19 in persons 60 years and above during SARS-CoV-2 Omicron XBB.1.5 and other XBB sublineages circulation, Italy, April to June 2023.

During predominant circulation of SARS-CoV-2 Omicron XBB.1.5 and other XBB sublineages (April-June 2023), we found that a second or third booster of Comirnaty bivalent Original/Omicron BA.4-5 mRNA vaccine, versus a first booster received at least 120 days earlier, was effective in preventing severe COVID-19 for more than 6 months post-administration in persons 60 years and above. In view of autumn 2023 vaccination campaigns, use of bivalent Original/Omicron BA.4-5 mRNA vaccines might be warranted until monovalent COVID-19 vaccines targeting Omicron XBB.1 sublineages become available.

Protection against severe COVID-19 after second booster dose of adapted bivalent (original/Omicron BA.4-5) mRNA vaccine in persons ≥ 60 years, by time since infection, Italy, 12 September to 11 December 2022.

Effectiveness against severe COVID-19 of a second booster dose of the bivalent (original/BA.4-5) mRNA vaccine 7-90 days post-administration, relative to a first booster dose of an mRNA vaccine received ≥ 120 days earlier, was ca 60% both in persons ≥ 60 years never infected and in those infected > 6 months before. Relative effectiveness in those infected 4-6 months earlier indicated no significant additional protection (10%; 95% CI: -44 to 44). A second booster vaccination 6 months after the latest infection may be warranted.

Winning during a pandemic: epidemiology of SARS-CoV-2 during EURO2020 in Italy.

INTRODUCTION: EURO2020 generated a growing media and population interest across the month period, that peaked with large spontaneous celebrations across the country upon winning the tournament. METHODS: We retrospectively analysed data from the national surveillance system (indicator-based) and from event-based surveillance to assess how the epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) changed in June-July 2021 and to describe cases and clusters linked with EURO2020. RESULTS: Widespread increases in transmission and case numbers, mainly among younger males, were documented in Italy, none were linked with stadium attendance. Vaccination coverage against SARS-CoV-2 was longer among cases linked to EURO2020 than among the general population. CONCLUSIONS: Transmission increased across the country, mainly due to gatherings outside the stadium, where, conversely, strict infection control measures were enforced. These informal 'side' gatherings were dispersed across the entire country and difficult to control. Targeted communication and control strategies to limit the impact of informal gatherings occurring outside official sites of mass gathering events should be further developed.

Risk and protective factors for SARS-CoV-2 reinfections, surveillance data, Italy, August 2021 to March 2022.

We explored the risk factors associated with SARS-CoV-2 reinfections in Italy between August 2021 and March 2022. Regardless of the prevalent virus variant, being unvaccinated was the most relevant risk factor for reinfection. The risk of reinfection increased almost 18-fold following emergence of the Omicron variant compared with Delta. A severe first SARS-CoV-2 infection and age over 60 years were significant risk factors for severe reinfection.

A community-acquired Legionnaires' disease outbreak caused by Legionella pneumophila serogroup 2: an uncommon event, Italy, August to October 2018.

In September 2018 in Brescia province, northern Italy, an outbreak of Legionnaires' disease (LD) caused by Legionella pneumophila serogroup 2 (Lp2) occurred. The 33 cases (two fatal) resided in seven municipalities along the Chiese river. All cases were negative by urinary antigen test (UAT) and most were diagnosed by real-time PCR and serology. In only three cases, respiratory sample cultures were positive, and Lp2 was identified and typed as sequence type (ST)1455. In another three cases, nested sequence-based typing was directly applied to respiratory samples, which provided allelic profiles highly similar to ST1455. An environmental investigation was undertaken immediately and water samples were collected from private homes, municipal water systems, cooling towers and the river. Overall, 533 environmental water samples were analysed and 34 were positive for Lp. Of these, only three samples, all collected from the Chiese river, were Lp2 ST1455. If and how the river water could have been aerosolised causing the LD cases remains unexplained. This outbreak, the first to our knowledge caused by Lp2, highlights the limits of UAT for LD diagnosis, underlining the importance of adopting multiple tests to ensure that serogroups other than serogroup 1, as well as other Legionella species, are identified.

Impact of lockdown on the microbiological status of the hospital water network during COVID-19 pandemic.

The COVID-19 pandemic started in China in early December 2019, and quickly spread around the world. The epidemic gradually started in Italy at the end of February 2020, and by May 31, 2020, 232,664 cases and 33,340 deaths were confirmed. As a result of this pandemic, the Italian Ministerial Decree issued on March 11, 2020, enforced lockdown; therefore, many social, recreational, and cultural centers remained closed for months. In Apulia (southern Italy), all non-urgent hospital activities were suspended, and some wards were closed, with a consequent reduction in the use of the water network and the formation of stagnant water. This situation could enhance the risk of exposure of people to waterborne diseases, including legionellosis. The purpose of this study was to monitor the microbiological quality of the water network (coliforms, E. coli, Enterococci, P. aeruginosa, and Legionella) in three wards (A, B and C) of a large COVID-19 regional hospital, closed for three months due to the COVID-19 emergency. Our study revealed that all three wards' water network showed higher contamination by Legionella pneumophila sg 1 and sg 6 at T1 (after lockdown) compared to the period before the lockdown (T0). In particular, ward A at T1 showed a median value = 5600 CFU/L (range 0-91,000 CFU/L) vs T0, median value = 75 CFU/L (range 0-5000 CFU/L) (p-value = 0.014); ward B at T1 showed a median value = 200 CFU/L (range 0-4200 CFU/L) vs T0, median value = 0 CFU/L (range 0-300 CFU/L) (p-value = 0.016) and ward C at T1 showed a median value = 175 CFU/L (range 0-22,000 CFU/L) vs T0, median value = 0 CFU/L (range 0-340 CFU/L) (p-value < 0.001). In addition, a statistically significant difference was detected in ward B between the number of positive water samples at T0 vs T1 for L. pneumophila sg 1 and sg 6 (24% vs 80% p-value < 0.001) and for coliforms (0% vs 64% p-value < 0.001). Moreover, a median value of coliform load resulted 3 CFU/100 ml (range 0-14 CFU/100 ml) at T1, showing a statistically significant increase versus T0 (0 CFU/100 ml) (p-value < 0.001). Our results highlight the need to implement a water safety plan that includes staff training and a more rigorous environmental microbiological surveillance in all hospitals before occupying a closed ward for a longer than one week, according to national and international guidelines.

Epidemiological characteristics of COVID-19 cases and estimates of the reproductive numbers 1 month into the epidemic, Italy, 28 January to 31 March 2020.

BackgroundOn 20 February 2020, a locally acquired coronavirus disease (COVID-19) case was detected in Lombardy, Italy. This was the first signal of ongoing transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the country. The number of cases in Italy increased rapidly and the country became the first in Europe to experience a SARS-CoV-2 outbreak.AimOur aim was to describe the epidemiology and transmission dynamics of the first COVID-19 cases in Italy amid ongoing control measures.MethodsWe analysed all RT-PCR-confirmed COVID-19 cases reported to the national integrated surveillance system until 31 March 2020. We provide a descriptive epidemiological summary and estimate the basic and net reproductive numbers by region.ResultsOf the 98,716 cases of COVID-19 analysed, 9,512 were healthcare workers. Of the 10,943 reported COVID-19-associated deaths (crude case fatality ratio: 11.1%) 49.5% occurred in cases older than 80 years. Male sex and age were independent risk factors for COVID-19 death. Estimates of R0 varied between 2.50 (95% confidence interval (CI): 2.18-2.83) in Tuscany and 3.00 (95% CI: 2.68-3.33) in Lazio. The net reproduction number Rt in northern regions started decreasing immediately after the first detection.ConclusionThe COVID-19 outbreak in Italy showed a clustering onset similar to the one in Wuhan, China. R0 at 2.96 in Lombardy combined with delayed detection explains the high case load and rapid geographical spread. Overall, Rt in Italian regions showed early signs of decrease, with large diversity in incidence, supporting the importance of combined non-pharmacological control measures.

Large community-acquired Legionnaires' disease outbreak caused by Legionella pneumophila serogroup 1, Italy, July to August 2018.

In July 2018, a large outbreak of Legionnaires' disease (LD) caused by Legionella pneumophila serogroup 1 (Lp1) occurred in Bresso, Italy. Fifty-two cases were diagnosed, including five deaths. We performed an epidemiological investigation and prepared a map of the places cases visited during the incubation period. All sites identified as potential sources were investigated and sampled. Association between heavy rainfall and LD cases was evaluated in a case-crossover study. We also performed a case-control study and an aerosol dispersion investigation model. Lp1 was isolated from 22 of 598 analysed water samples; four clinical isolates were typed using monoclonal antibodies and sequence-based typing. Four Lp1 human strains were ST23, of which two were Philadelphia and two were France-Allentown subgroup. Lp1 ST23 France-Allentown was isolated only from a public fountain. In the case-crossover study, extreme precipitation 5-6 days before symptom onset was associated with increased LD risk. The aerosol dispersion model showed that the fountain matched the case distribution best. The case-control study demonstrated a significant eightfold increase in risk for cases residing near the public fountain. The three studies and the matching of clinical and environmental Lp1 strains identified the fountain as the source responsible for the epidemic.

[Integrated Surveillance in Italy: outputs and related activities]. / La sorveglianza integrata COVID-19 in Italia: output e attività correlate.

OBJECTIVES: to describe the integrated surveillance system of COVID-19 in Italy, to illustrate the outputs used to return epidemiological information on the spread of the epidemic to the competent public health bodies and to the Italian population, and to describe how the surveillance data contributes to the ongoing weekly regional monitoring and risk assessment system. METHODS: the COVID-19 integrated surveillance system is the result of a close and continuous collaboration between the Italian National Institute of Health (ISS), the Italian Ministry of Health, and the regional and local health authorities. Through a web platform, it collects individual data of laboratory confirmed cases of SARS-CoV-2 infection and gathers information on their residence, laboratory diagnosis, hospitalisation, clinical status, risk factors, and outcome. Results, for different levels of aggregation and risk categories, are published daily and weekly on the ISS website, and made available to national and regional public health authorities; these results contribute one of the information sources of the regional monitoring and risk assessment system. RESULTS: the COVID-19 integrated surveillance system monitors the space-time distribution of cases and their characteristics. Indicators used in the weekly regional monitoring and risk assessment system include process indicators on completeness and results indicators on weekly trends of newly diagnosed cases per Region. CONCLUSIONS: the outputs of the integrated surveillance system for COVID-19 provide timely information to health authorities and to the general population on the evolution of the epidemic in Italy. They also contribute to the continuous re-assessment of risk related to transmission and impact of the epidemic thus contributing to the management of COVID-19 in Italy.

Spatiotemporal distribution and determinants of measles incidence during a large outbreak, Italy, September 2016 to July 2018.

BackgroundMeasles is still endemic in Italy and outbreaks are frequent. From 2016 to 2018, more than 7,000 measles cases were reported to the national integrated measles and rubella surveillance system, the largest outbreak since implementation of this system.AimWe aimed to describe the characteristics and spatiotemporal distribution of measles cases in Italy and explore determinants of incidence at municipality level.MethodsWe performed a retrospective observational study, mapping by municipalityall measles cases reported to the national surveillance system with symptom onset between 1 September 2016 and 31 July 2018. We also analysed measles-mumps-rubella (MMR) vaccination coverage (VC) data (2000-2017) for the first and second dose, collected from the Ministry of Health. We used regression analysis to explore factors associated with measles incidence at municipality level.ResultsWe analysed 7,854 cases, 3,927 (50%) female. Median age was 26 years; 475 cases (6%) were younger than 1 year. The outbreak occurred in two epidemic waves. The first started in central/northern regions (end of 2016), the second (mostly within 2018) was concentrated in southern regions. In 2016 and 2017, national VC was below 95% for both MMR doses. In 2017, only one region reported VC above 95% for the first dose. At municipality level, incidence was associated with higher urbanisation, less deprivation and fewer adults.ConclusionThe spread of measles between September 2016 and July 2018 in Italy indicates the need to improve VC and to explore further how societal and other parameters might be linked to incidence.

Childhood vaccinations: knowledge, attitudes and practices of paediatricians and factors associated with their confidence in addressing parental concerns, Italy, 2016.

BackgroundPaediatrician recommendations are known to influence parental vaccine decisions.AimOur aim was to examine vaccination knowledge, attitudes and practices among paediatricians in Italy and identify factors associated with their confidence in addressing parental questions.MethodsAn electronic questionnaire survey was conducted from February to March 2016, among a sample of Italian paediatricians.ResultsThe survey was completed by 903 paediatricians (mean age: 56 years). Of 885 who responded to the specific question, 843 (95.3%) were completely favourable to vaccinations. Sixty-six per cent (570/862) felt sufficiently knowledgeable about vaccinations and vaccine-preventable diseases to confidently discuss them with parents. Paediatricians who were male, who were 55 years or older, who had participated in training courses in the last 5 years, who reported that taking courses and reading the scientific literature had contributed to their knowledge, or who had implemented vaccination promotion activities, felt more knowledgeable than other paediatricians. When asked to rate their level of agreement with statements about vaccine safety and effectiveness, only 8.9% (80/903) responded fully as expected. One third (294/878) did not systematically verify that their patients are up to date with the immunisation schedule. Only 5.4% (48/892) correctly identified all true and false contraindications.ConclusionsThe majority of paediatricians in Italy are favourable to vaccination but gaps were identified between their overall positive attitudes and their knowledge, beliefs and practices. Targeted interventions are needed aimed at increasing paediatricians' confidence in addressing parents' concerns, strengthening trust towards health authorities and improving systems barriers.

Improvement of Legionnaires' disease diagnosis using real-time PCR assay: a retrospective analysis, Italy, 2010 to 2015.

AimTo evaluate real-time PCR as a diagnostic method for Legionnaires' disease (LD). Detection of Legionella DNA is among the laboratory criteria of a probable LD case, according to the European Centre for Disease Prevention and Control, although the utility and advantages, as compared to culture, are widely recognised.MethodsTwo independent laboratories, one using an in-house and the other a commercial real-time PCR assay, analysed 354 respiratory samples from 311 patients hospitalised with pneumonia between 2010-15. The real-time PCR reliability was compared with that of culture and urinary antigen tests (UAT). Concordance, specificity, sensitivity and positive and negative predictive values (PPV and NPV, respectively) were calculated.ResultsOverall PCR detected eight additional LD cases, six of which were due to Legionella pneumophila (Lp) non-serogroup 1. The two real-time PCR assays were concordant in 99.4% of the samples. Considering in-house real-time PCR as the reference method, specificity of culture and UAT was 100% and 97.9% (95% CI: 96.2-99.6), while the sensitivity was 63.6% (95%CI: 58.6-68.6) and 77.8% (95% CI: 72.9-82.7). PPV and NPV for culture were 100% and 93.7% (95% CI: 91.2-96.3). PPV and NPV for UAT were 87.5% (95% CI: 83.6-91.4) and 95.8% (95% CI: 93.5-98.2).ConclusionRegardless of the real-time PCR assay used, it was possible to diagnose LD cases with higher sensitivity than using culture or UAT. These data encourage the adoption of PCR as routine laboratory testing to diagnose LD and such methods should be eligible to define a confirmed LD case.

Underreporting of congenital rubella in Italy, 2010-2014.

In accordance with the goals of the World Health Organization Regional Committee for Europe, the Italian national Measles and Rubella Elimination Plan 2010-2015 aimed to reduce the incidence of congenital rubella cases to <1 case/100,000 live births by 2015. In Italy, a passive national surveillance system for congenital rubella and rubella in pregnancy is active since 2005. We estimated the degree of underreporting of congenital rubella, performing a capture-recapture analysis of cases detected through two independent sources: the national surveillance system and the national hospital discharge database, in the years 2010-2014. We found that 6 out of 11 cases tracked in the retrospective case-finding from hospital registries had not been notified to the surveillance system, and we estimated a degree of underreporting of 53% for the period 2010-2014. This approach showed to be simple to perform, repeatable, and effective. CONCLUSION: In order to reduce underreporting, some actions aimed at strengthening surveillance procedures are needed. The adoption on a routine basis of the review of hospital discharge registries for case-finding, monthly zero-reporting, and actions to train and sensitize all the specialists involved in the care of pregnant women and the newborns to notification procedures are recommended. What is Known • In Italy, the incidence of congenital rubella was below the WHO target of 1/100,000 live births in 2005-2015, except for two peaks in 2008 and 2012 (5 and 4/100,000, respectively). • Further efforts are required to improve congenital rubella surveillance so that it is more sensitive and specific. The WHO proposes retrospective case-finding from hospital records as an alternative approach to detect infants with congenital rubella. What is New • Underreporting of congenital rubella in Italy was 53% in 2010-2014. • Hospital discharge registries resulted to be an appropriate source to detect congenital rubella cases.

Ongoing outbreak with well over 4,000 measles cases in Italy from January to end August 2017 - what is making elimination so difficult?

We report an ongoing measles outbreak in Italy, with over 4,400 cases reported in 20 Regions from January to August 2017. Median age was 27 years, 88% of the cases were unvaccinated. The highest incidence was in infants below one year of age and 7% of cases occurred among healthcare workers. Three deaths occurred and two cases of encephalitis were reported. Wide immunity gaps and nosocomial transmission are major challenges to measles elimination in Italy.

Extensive Nosocomial Transmission of Measles Originating in Cruise Ship Passenger, Sardinia, Italy, 2014.

We report a measles outbreak in Sardinia, Italy, that originated in a cruise ship passenger. The outbreak showed extensive nosocomial transmission (44 of 80 cases). To minimize nosocomial transmission, health care facilities should ensure that susceptible health care workers are vaccinated against measles and should implement effective infection control procedures.

Promotion of influenza vaccination among health care workers: findings from a tertiary care children's hospital in Italy.

BACKGROUND: The aims of this study were: a) to evaluate attitudes and practices of health care workers (HCWs) towards influenza vaccination and their opinion regarding a vaccination promotion toolkit; b) to estimate hospital HCWs' influenza vaccination coverage rates (VC). METHODS: The Bambino Gesù Children's Hospital (OPBG) is an academic hospital in Italy. Since 2009, free influenza vaccination is offered to HCWs during working hours. In October-December 2013, a communication campaign based on a standardized toolkit was conducted. In December 2013, we performed a cross-sectional survey in a sample of hospital wards, based on a self-administered questionnaire including participants' characteristics; self-reported influenza vaccination history; reasons for vaccination or missed vaccination; opinion regarding the toolkit. Multivariable logistic analysis was used to assess independent predictors of influenza vaccination status. Annual VC for years 2009-2013 was estimated by using the number of seasonal influenza vaccine doses administered to HCWs as numerator, and the number of hospital HCWs as denominator. RESULTS: Out of 191 HCWs who participated in the survey, 35.6% reported at least one influenza vaccination during their life; 6.8% adhered to annual revaccination. Years of service and professional category were significantly and independently associated with vaccination (adjusted-OR: 2.4 for > 10 years of service, compared to < 5 years of service; adjusted-OR: 2.6 for physicians compared to nurses). Patient protection was the main reported reason for vaccination (34.3%); considering influenza a mild disease was the main reason for non-vaccination (36.9%); poor vaccine effectiveness was the main reason for missed annual revaccination (28.8%). Overall, 75% of respondents saw at least one promotion tool; 65.6% of them found the information useful. Hospital VC decreased from 30% in 2009, to 5% in 2012. In 2013, VC was 14%. CONCLUSIONS: Satisfactory influenza VC in HCWs is hard to achieve. In 2013, along with the toolkit implementation, we observed an increase in HCWs' vaccination coverage, nevertheless, it remained unsatisfactory. Tailored information strategies targeting nurses and recently employed HCWs should be implemented. Institution of declination statements, adding influenza vaccination to financial incentive systems, or vaccination requirements should also be considered to increase influenza VC among HCWs.

Molecular typing of Legionella pneumophila serogroup 1 clinical strains isolated in Italy.

Molecular typing methods for discriminating different bacterial isolates are essential epidemiological tools in prevention and control of Legionella infections and outbreaks. A selection of 56 out of 184 Legionella pneumophila serogroup 1 (Lp1) clinical isolates, collected from different Italian regions between 1987 and 2012, and stored at the National Reference Laboratory for Legionella, were typed by monoclonal antibody (MAb) subgrouping, amplified fragment length polymorphism (AFLP) and sequence based typing (SBT). These strains were isolated from 39 community (69.6%), 14 nosocomial (25%) and 3 travel associated (5.4%) Legionnaires'disease cases. MAb typing results showed a prevalence of MAb 3/1 positive isolates (75%) with the Philadelphia subgroup representing 35.7%, followed by Knoxville (23.2%), Benidorm (12.5%), Allentown/France (1.8%), Allentown/France-Philadelphia (1.8%). The remaining 25% were MAb 3/1 negative, namely 11 Olda (19.6%), 2 Oxford (3.6%) and 1 Bellingham (1.8%) subgroups. AFLP analysis detected 20 different genomic profiles. SBT analysis revealed 32 different sequence types (STs) with high diversity of STs (IODSTs=0.952) 12 of which were never described before. ST1 and ST23 were most frequently isolated as observed worldwide. A helpful analysis of data from SBT, MAb subgrouping and AFLP is provided, as well as a comparison to the Lp1 types investigated from other countries. This study describes the first Italian Lp1 strains database, providing molecular epidemiology data useful for future epidemiological investigations, especially of travel associated Legionnaires' diseases (TALD) cases, Italy being the country associated with the highest number of clusters.