Influenza vaccination in the elderly: why are the overall benefits still hotly debated?

The exact magnitude of the benefit of influenza vaccine among elderly individuals is subject of considerable debated. Existing vaccine effectiveness estimates come mostly from observational studies, which may be biased because of difficulties in identifying and adjusting for confounders. In this paper, we examine the potential sources of bias in observational studies of influenza vaccine effectiveness in the elderly and we discuss available evidence regarding the efficacy and effectiveness of licensed influenza vaccines. Although several methodological criticisms among the available analyses on seasonal vaccines for elderly were identified, overall seasonal influenza vaccines showed relevant efficacy/effectiveness in reducing the risk of influenza and its complications in the elderly, considering different measure of outcome.

Improving the protection against Streptococcus pneumoniae with the new generation 13-valent pneumococcal conjugate vaccine.

The wide use of the 7-valent Pneumococcal Conjugate Vaccine (PCV7) determined, during the last decade, a dramatic decline in the incidence of Invasive Pneumococcal Diseases (IPD) in infants and children, and also among the non-vaccinated population through the phenomenon known as "herd protection". Furthermore a significant reduction of some non-IPD, such as Community Acquired Pneumonia (CAP) and Acute Otitis Media (AOM) was reported among the pediatric population. At the same time, the high vaccination coverage rates reached with PCV7 contributed to modify the ecology of Streptococcus pneumoniae (Sp), favoring the emergence of some serotypes not included in PCV7 and involved in IPD (replacement phenomenon), thus partially affecting the positive effects of the pediatric immunization programs. To remedy these shortcomings, a new generation of conjugate vaccines, with an enlarged antigenic spectrum of activity than PCV7, has been available since 2010. In particular, the 13-valent Pneumococcal Conjugate Vaccine (PCV13) has been authorized for active prevention of IPD, CAP and AOM in infants and children aged between 6 months and 5 years. More recently, in September 2011, the European Medicine Agency extended the indication for its use to include active immunization of adults aged > or = 50 years for the prevention of IPD, thus opening new interesting opportunities to improve the control of pneumococcal disease among the entire population. The most interesting results from clinical trials using PCV13 in both children and adults are reported and discussed in details.

Bacterial carriage and respiratory tract infections in subjects > or = 60 years during an influenza season: implications for the epidemiology of community acquired pneumonia and influenza vaccine effectiveness.

INTRODUCTION: During the 2010/11 influenza season an epidemiological prospective cohort active study was organized, to evaluate etiologic role due to the main bacteria and viruses causing Community Acquired Pneumonia (CAP) and Influenza like-illness (ILl) in elderly and to explore the role of the bacterial nose-pharingeal carriage in subjects with respiratory tract infections. METHODS: An integrated active surveillance of a cohort of adults aged > or = 60 y based on a double prospective and retrospective mechanisms of capture of ILl and CAP cases was organized. Samples were collected from all ILI and CAP prospectively identified. The samples were be tested by multiplex PCR for detection of the main respiratory bacteria and viruses. RESULTS AND DISCUSSION: The study population amounted to 2,551 adults. During the 2010/11 influenza season, the ILl cumulative incidence was 4.2%, that was twice higher than that calculated by regional sentinel-based Influenza surveillance system during the 2010/11 season in the elderly (2.2%). Among 45 patients with ILI of which had been collected the swab, 17 (37.8%) were positive for influenza viruses and 2 (4.4%) for RSV, 6 (13.3%) patients carried Streptococcus pn and 6 (13.3%) Haemophilus in. In the same period, 7 CAP cases were observed; 3 cases were prospectively identified and samples were collected, while 4 cases were retrospectively detected. The CAP cumulative incidence was 0,3%. The influenza vaccine effectiveness in prevention of laboratory-confirmed influenza emerged by our study was 61%, in condition of good antigenic matching between vaccine and circulating strains observed during the 2010/11. These data contribute to better defining the epidemiological picture of upper and lower respiratory tract infections, fundamental information in light of the recent introduction of new vaccines for prevention of pneumonia in the elderly, including 13-valent conjugate pneumococcal vaccine.

Impact of influenza during the post-pandemic season: epidemiological picture from syndromic and virological surveillance.

INTRODUCTION: Following the observation that 1 or 2 pandemic peak due to the circulation ofAHINlv had occurred in most countries and in most World Health Organization (WHO) Regions, WHO declared on August 10"h, 2010 that the world was moving into the post-pandemic period, whose surveillance presents considerable interest both from epidemiological and clinical point of view. We described the epidemiological picture emerged from syndromic and virological surveillance during the post-pandemic season in Liguria, Italy. MATERIALS AND METHODS: An Emergency Department Syndrome surveillance system, based on data collected at "San Martino" and IRCCS "G. Gaslini" Liguria Regional Reference University Hospitals for adults and children is active since July 2007. Monitored syndromes include "Influenza-Like Illness" (ILl) and "Low Respiratory Tract Infections" (LRTI). The Ligurian Regional Reference laboratory for Influenza virological surveillance and diagnosis offers rapid detection of influenza viruses by real-time and block RT-PCR, viral culture and genetic characterization by entire sequence analysis of haemagglutinin- and neuraminidase-coding regions in accordance with the international standards established by the global laboratory network. RESULTS AND DISCUSSION: The integration of syndromic surveillance system and laboratory surveillance for rapid detection and characterization of the disease responsible agent represented a specific and sensitive tool for influenza surveillance. The post-pandemic season was characterized by early onset and by the heaviest impacts for ILI and LRTI among the recent epidemic seasons. In contrast to the picture observed during the pandemic season, the 2010/11 winter was characterized by the intensive circulation of pandemic AH1N1v coupled with sustained activity due to influenza B and Respiratory Syncytial Virus (RSV). Antigenic and molecular characterization of influenza strains confirmed the good matching between circulating and 2010/11 vaccine viruses.

Epidemiological and molecular approaches for management of a measles outbreak in Liguria, Italy.

Since March 2010 a measles outbreak has been occurred in Genoa, Liguria, an administrative Region in Northern Italy. Epidemiological and molecular data on the outbreak, obtained from the passive mandatory notification system, the laboratory surveillance and an innovative syndrome surveillance system, were investigated. Overall 39 cases were reported in the urban area. Information about demography, vaccination status, hospitalization and geographic distribution of measles cases are available. 19 cases (48.7%) were laboratory-confirmed and were characterized by sequence analysis: 18 strains belonged to genotype D8, so identifying a new measles variant within the Liguria population. Adopted control measures seem to have limited viral circulation. The outbreak allowed to test the efficacy of the 3 surveillance systems active in Liguria, highlighting their advantages and some important limitations. More efforts are needed to collect and integrate any epidemiological and virological available data in order to better describe the local measles transmission dynamics.

Hospital-acquired infections and leading pathogens detected in a regional university adult acute-care hospital in Genoa, Liguria, Italy: results from a prevalence study.

BACKGROUND: A prevalence study aimed to update the epidemiological scenario of Hospital-Acquired Infections (HAI) was performed at the San Martino University Hospital of Genoa, the Regional Reference Adult-care Center in Liguria, Italy, with more than 1300 beds. MATERIALS AND METHODS: The investigation was performed in all the wards, except the Psychiatric Units, between 19th March and 6Ih April, 2007, using a one-day monitoring system for each ward. International standardized criteria and definitions for the surveillance of HAI were used for the collection of data, which were recorded in specific software for subsequent consolidation, analysis and quality control. RESULTS: The hospital infection control staff actively monitored 912 inpatients: a total of 84 HAI among 72 patients were diagnosed, with an overall prevalence of infections and affected cases of 9.2% (95% CI: 7.3-11.1) and 7.9% (95% CI: 6.1-9.7), respectively. Urinary Tract Infections (UTI) (30.9%), Respiratory Tract Infections (RTI) (28.6%) and Blood Stream Infections (BSI) (21.4%) were found to be the most frequent infections. As expected, both specific prevalence and localization of HAI varied considerably between wards, with the highest values recorded in Intensive Care Units (ICU) and in Functional Rehabilitation wards. RTI (26.3%) and BSI (13.2%) were found primarily represented in ICU, while the highest values of UTI (13.3%) were registered in Functional Rehabilitation Units. Enterococcus spp. (16.8%), Candida spp. (14%), Pseudomonas spp. (12.2), Staphylococcus aureus (10.7%), Escherichia coli (10.3%) and Coagulase-negative staphylococci (CNS) (9.3%) were the most frequent pathogens isolated. The overall rate of administration of antibiotics was 55.3% and penicillin (26.7%), cephalosporins (22.8%) and fluoroquinolones (17.9%) were found to be the leading antibacterial administered. CONCLUSION: Results of the present study have been, and are currently, used for orientating surveillance and control hospital policies, planning activities according to a rational and evidence-based approach.

Role of congenital rubella reference laboratory: 21-months-surveillance in Liguria, Italy.

INTRODUCTION: Rubella is generally a mild rush fever disease when acquired in childhood, but when infection occurs during the first months of pregnancy, high risk of trans-placental transmission to the foetus and of congenital anomalies exists. In November 2003, a National Plan for measles and congenital rubella elimination was approved in Italy. The aim was to reduce and maintain Congenital Rubella Syndrome incidence lower than 1 case per 100,000 live births/year by 2007. Since June 2006, Liguria Administrative Region recognized U.O. Hygiene, "San Martino" University Hospital, Genoa, as regional reference laboratory for diagnosis of rubella infection during pregnancy and post-partum. METHODS: Twenty-one-month virological-surveillance results between April 2007 and December 2008 were reported in terms of demographic data, risk factors, access reasons, clinical picture, vaccination, previous rubella disease, laboratory results of pregnant women and newborns. RESULTS AND CONCLUSION: Since the beginning of surveillance, 65 pregnant women with suspected virus infection and 18 newborns with suspected congenital rubella were followed up. The results of laboratory surveillance highlighted (i) the importance of an early screening, (ii) the suboptimal specificity of chemiluminescent assays, that often yield false positive IgM results and (iii) the fundamental role of second-level laboratory to confirm the serological diagnosis and to detect the virus by molecular techniques.

Three-year (1999-2002) of epidemiological and virological surveillance of influenza in north-east Italy.

The results of the epidemiological and virological surveillance of influenza performed during the 1999/2000, 2000/2001 and 2001/2002 seasons in the northeastern Italy were presented and the relationship between age-specific morbidity rates and circulating strains were discussed.The epidemiological findings pointed out a change in age distribution. During the 1999/2000 season, characterized by a circulation of viruses antigenically close to the vaccine strain, a similar incidence rate in the 0-14 and 15-64-year-old groups was observed, while during the 2001/ 2002 winter the virus infected mostly children. During 2001/2002 season, B type viruses predominated with at least three distinguishable molecular variants. In particular, B/Victoria/2/87-like viruses re-emerged after more than a decade, and the antibodies elicited by the vaccine strain and by the strains circulating in previous seasons were poor or not protecting. The accumulation of susceptible subjects in young age group during the 1990s, due to the lack of circulation of B/Victoria/2/87-like viruses, was responsible for the unusual morbidity in the 0-14 year group. No circulation of B/Victoria/2/87-like viruses was observed in > 64-year-old group during 2001/2002 epidemic, probably due to a long-lasting immunity against viruses belonging to this lineage.

An outbreak of hepatitis C virus in a haemodialysis unit: molecular evidence of patient-to-patient transmission.

Hepatitis C virus (HCV) infection remains a major problem in haemodialysis units despite the risk decrease provided by anti-HCV screening of blood. The exact mode of transmission of HCV in the dialysis units remains unclear. To identify the route of the virus and the mechanisms of transmission an investigation into the outbreak of HCV infection in a haemodialysis unit on a molecular level was held: 12 newly infected patients and 14 already infected were investigated by sequencing the 5' untranslated region of the viral genome. The results showed that 3 strains infected new cases and these strains matched those sequenced in already infected patients. Transmission occurred between patients treated on the same shift and also between different rooms. Console and blood or blood product contamination was excluded. Our study gave molecular evidence of patient-to-patient transmission of HCV in a haemodialysis unit. Our data underline the importance of the strict enforcement of standard precautions to prevent HCV transmission and failure of the isolation of anti-HCV positive patients as preventive measure.