Quadrivalent influenza vaccine: a new opportunity to reduce the influenza burden.

Influenza illness is caused by influenza A and influenza B strains. Although influenza A viruses are perceived to carry greater risk because they account for the majority of influenza cases in most seasons and have been responsible for influenza pandemics, influenza B viruses also impose a substantial public health burden, particularly among children and at-risk subjects. Furthermore, since the 2001-2002 influenza season, both influenza B lineages, B/Victoria-like viruses and B/Yamagata-like viruses have co-circulated in Europe. The conventional trivalent influenza vaccines have shown a limited ability to induce effective protection when major or minor mismatches between the influenza B vaccine component and circulating strains occur. For this reason, the inclusion of a second B strain in influenza vaccines may help to overcome the well-known difficulties of predicting the circulating B lineage and choosing the influenza B vaccine component. Two quadrivalent influenza vaccines, a live-attenuated quadrivalent influenza vaccine (Q/LAIV) and a split inactivated quadrivalent influenza vaccine (I/QIV), were first licensed in the US in 2012. Since their introduction, models simulating the inclusion of QIV in influenza immunization programs have demonstrated the substantial health benefits, in terms of reducing the number of influenza cases, their complications and mortality. In the near future, evaluations from simulation models should be confirmed by effectiveness studies in the field, and more costeffectiveness analyses should be conducted in order to verify the expected benefits.

Determinants of adherence to seasonal influenza vaccination among healthcare workers from an Italian region: results from a cross-sectional study.

OBJECTIVES: Notwithstanding decades of efforts to increase the uptake of seasonal influenza (flu) vaccination among European healthcare workers (HCWs), the immunisation rates are still unsatisfactory. In order to understand the reasons for the low adherence to flu vaccination, a study was carried out among HCWs of two healthcare organisations in Liguria, a region in northwest Italy. METHODS: A cross-sectional study based on anonymous self-administered web questionnaires was carried out between October 2013 and February 2014. Through univariate and multivariate regression analysis, the study investigated the association between demographic and professional characteristics, knowledge, beliefs and attitudes of the study participants and (i) the seasonal flu vaccination uptake in the 2013/2014 season and (ii) the self-reported number of flu vaccination uptakes in the six consecutive seasons from 2008/2009 to 2013/2014. RESULTS: A total of 830 HCWs completed the survey. Factors statistically associated with flu vaccination uptake in the 2013/2014 season were: being a medical doctor and agreeing with the statements 'flu vaccine is safe', 'HCWs have a higher risk of getting flu' and 'HCWs should receive flu vaccination every year'. A barrier to vaccination was the belief that pharmaceutical companies influence decisions about vaccination strategies. DISCUSSION: All the above-mentioned factors, except the last one, were (significantly) associated with the number of flu vaccination uptakes self-reported by the respondents between season 2008/2009 and season 2013/2014. Other significantly associated factors appeared to be level of education, being affected by at least one chronic disease, and agreeing with mandatory flu vaccination in healthcare settings. CONCLUSIONS: This survey allows us to better understand the determinants of adherence to vaccination as a fundamental preventive strategy against flu among Italian HCWs. These findings should be used to improve and customise any future promotion campaigns to overcome identified barriers to immunisation.

Increasing incidence of Clostridium difficile infections: results from a 5-year retrospective study in a large teaching hospital in the Italian region with the oldest population.

Limited information is available on the incidence of Clostridium difficile infections (CDIs) in Italian hospitals. In this study, we assessed the changes in the incidence of CDI over a 5-year period in a teaching hospital in Liguria, the Italian region with the oldest population. Secondary endpoints were the development of severe CDI and 30-day mortality. The annual incidence of CDI/10000 patient-days significantly increased from 0·54 in 2010 to 3·04 in 2014 (χ 2 for trend, P < 0·001). The median age of patients with CDI was 81 years. As many as 81% and 89% of these patients had comorbid conditions and previous exposure to antibiotics, respectively. In the multivariate analysis of risk factors for severe CDI, previous therapy with histamine 2 blockers and low serum albumin were associated with severe CDI, while diabetes appeared to be protective. In the multivariate model of risk factors for 30-day mortality, high leukocyte count, low serum albumin, and increased serum creatinine were unfavourably associated with outcome. Strict adherence to infection control measures was of utmost importance to counteract the increasing incidence of CDI in our hospital, particularly because of the advanced age of the patients and their very high frequency of chronic conditions and use of antibiotics, which readily predispose them to the development of CDI.

Methodological criticisms in the evaluation of Pneumococcal Conjugate Vaccine effectiveness.

Globally, lower respiratory tract infections (LRTIs), including community-acquired pneumonia (CAP), cause considerable of morbidity and mortality in adults, especially in the elderly. In addition to age, underlying medical conditions are associated with an increased risk of CAP. From an aetiological point of view, Streptococcus pneumoniae is the leading cause of adult CAP throughout the world. Two types of vaccine are available for the prevention of pneumococcal diseases: the pneumococcal polysaccharide vaccine (PPV23) and the pneumococcal conjugate vaccine (PCV7, PCV10 and PCV13). An accurate understanding of the LRTIs burden and the types of subjects at risk of CAP, allow to find an appropriately targeted immunization strategy and provide baseline data to evaluate pneumococcal vaccine effectiveness. Given the high variability in available estimates of LRTIs burden and associated risk factors, the objective of the study was to discuss the methodological criticism in its evaluation, in the light of the gradual introduction of PCV13 immunization strategy targeted to elderly and risk groups in middle-high income countries.

Herpes Zoster: the rationale for the introduction of vaccination in Italy.

Herpes Zoster (HZ) and its main complication, post-herpetic neuralgia (PHN), represent an important public health issue because of their relevant burden within older adult population and the actual suboptimal therapeutic management of the diseases. Incidences of HZ and PHN are comparable all over the world and are closely related with the population age. Epidemiological data collected in Italy about HZ and its complications confirmed the trend registered in North America and Europe. Moreover HZ related burden is exacerbated by a significant economic impact related to both direct and indirect costs. Since 2006 a live, attenuated varicella zoster virus vaccine, that contains VZV Oka strain [Zostavax, Merck & Co., Inc.], was licensed for the prevention of HZ and PHN in adults aged ≥ 60 years. Since 2011, the licensure has been extended to adults between 50 and 59 years. The vaccine has demonstrated a good immunogenicity, efficacy and safety profiles in two pivotal phase III clinical trials and the effectiveness was further confirmed after vaccine licensure. Pharmaco-economic studies concluded that HZ vaccine is cost-effective in most European countries and generally supported the economic value of this vaccination. The vaccine is actually recommended in USA, Canada and several European countries. The opportunity to reduce the burden of these diseases by the recommendation of HZ vaccination have been evaluated and suggested also in our Country and some Regions have been recently introduced the vaccine in their immunization plan. If the good results, already obtained with HZ vaccine in other countries, will be confirmed by these Italian pilot experiences, vaccination programs should be made uniform in all Country in order to ensure an equitable offer of this important preventive tool.

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.