Alexander Domnich

Epidemiology of tick-borne encephalitis (TBE) in Europe and its prevention by available vaccines

Tick-borne Encephalitis (TBE), which is caused by a Flavivirus, is the most common tick-transmitted disease in Central and Eastern Europe and Russia. Today, TBE is endemic in 27 European countries, and has become an international public health problem. The epidemiology of TBE is changing owing to various factors, such as improvements in diagnosis and case reporting, increased recreational activities in areas populated by ticks, and changes in climatic conditions affecting tick habitats. Vaccination remains the most effective protective measure against TBE for people living in risk zones, occupationally exposed subjects and travelers to endemic areas. The vaccines currently in use are FSME-Immun®, Encepur®, EnceVir® and TBE vaccine Moscow®. The numerous studies performed on the efficacy and safety of these vaccines have shown a high level of immunogenicity and an excellent safety profile. Several studies have also shown a high level of cross-protection among strains belonging to different subtypes. In the present paper we attempted to describe the continuously changing epidemiology of TBE in European States and to overview clinical development of available vaccines paying particular attention on cross-protection elicited by the vaccines.

Effectiveness of MF59-adjuvanted seasonal influenza vaccine in the elderly: A systematic review and meta-analysis.

BACKGROUND In the elderly, traditional influenza inactivated vaccines are often only modestly immunogenic, owing to immunosenescence. Given that adjuvantation is a means of enhancing the immune response, the trivalent inactivated vaccine adjuvanted with MF59 (MF59-TIV) was specifically designed to overcome this problem. Considering that, for ethical reasons, the absolute effectiveness of an influenza vaccine in the elderly cannot be demonstrated in placebo-controlled studies, the present study aimed to assess the effectiveness of MF59-TIV in preventing influenza-related outcomes in the elderly. METHODS We conducted a systematic review of observational studies aimed at evaluating the effectiveness of MF59-TIV against influenza-related outcomes. Results of single studies were pooled whenever possible. RESULTS Of the 1993 papers screened, 11 (6 case-control, 3 cohort and 2 prospective case-control) studies were identified. Hospitalization due to pneumonia/influenza and laboratory-confirmed influenza were reported in more than one study, while other outcomes (influenza-like illness, cardio- and cerebrovascular accidents) were investigated only by one study each. Pooled analysis of four case-control studies showed an adjusted MF59-TIV effectiveness of 51% (95% CI: 39-61%) against hospitalizations for pneumonia/influenza among community-dwelling seniors. Pooled results of the adjusted vaccine effectiveness against laboratory-confirmed influenza were also high (60.1%), although the 95% CI passed through zero (-1.3 to 84.3%). Other single community-based studies showed very high effectiveness of MF59-TIV in preventing hospitalizations for acute coronary [87% (95% CI: 35-97%)] and cerebrovascular [93% (95% CI: 52-99%)] events. MF59-TIV proved highly effective [94% (95% CI: 47-100%] in reducing influenza-like illness among institutionalized elderly. Furthermore, MF59-TIV displayed greater efficacy than non-adjuvanted vaccines in preventing hospitalizations due to pneumonia/influenza [adjusted risk ratio 0.75 (95% CI: 0.57-0.98)] and laboratory-confirmed influenza [adjusted odds ratio 0.37 (0.14-0.96)]. CONCLUSIONS Our results suggest that MF59-TIV is effective in reducing several influenza-related outcomes among the elderly, especially hospitalizations due to influenza-related complications.

The “healthy immigrant” effect: does it exist in Europe today?

Several studies, carried out mainly in the United States and Canada, have suggested that recent immigrants are generally healthier than native-born populations in spite of the fact that they frequently have a lower socioeconomic status and less access to healthcare services. This “epidemiological paradox” has been called the “healthy immigrant” effect and is usually attributed to a self-selection process prior to migration, “cultural buffering” and official health screening and employability in receiving countries. In this paper, we have evaluated the European scientific research into the existence of the “healthy immigrant” effect.

An overview of current and potential use of information and communication technologies for immunization promotion among adolescents

Information and communication technologies (ICT), such as the Internet or mobile telephony, have become an important part of the life of today’s adolescents and their main means of procuring information. The new generation of the Internet based on social-networking technologies, Web 2.0, is increasingly used for health purposes by both laypeople and health professionals. A broad spectrum of Web 2.0 applications provides several opportunities for healthcare workers, in that they can reach large numbers of teenagers in an individualized way and promote vaccine-related knowledge in an interactive and entertaining manner. These applications, namely social-networking and video-sharing websites, wikis and microblogs, should be monitored in order to identify current attitudes toward vaccination, to reply to vaccination critics and to establish a real-time dialog with users. Moreover, the ubiquity of mobile telephony makes it a valuable means of involving teenagers in immunization promotion, especially in developing countries.

Flucelvax (Optaflu) for seasonal influenza

Conventional egg-based manufacturing technology for seasonal influenza vaccines has several drawbacks, including its inflexibility, reliance on egg supplies, risk of contamination, absence of growth of some isolates and egg-adaptive viral mutations that threaten vaccine matching. To overcome these limitations, cell culture-derived vaccines have been designed, including the trivalent inactivated vaccine Flucelvax®/Optaflu® (brand names in the US/EU, respectively). Flucelvax/Optaflu has gained wide regulatory approval and is currently implemented in several countries. Non-clinical studies have assuaged hypothetical concerns regarding oncogenicity and use in persons allergic to dogs. Ample clinical data suggest the non-inferiority of Flucelvax/Optaflu to egg-based vaccines in terms of immunogenicity, safety and tolerability, and it has fulfilled American and European mandatory requirements. Although Flucelvax/Optaflu is currently indicated only for adults and the elderly, pediatric data indicate its good immunogenicity and safety. This paper provides an update on the clinical development of Flucelvax/Optaflu, its seasonal trials and available post-marketing surveillance data.

Neisseria meningitidis B vaccines: recent advances and possible immunization policies

Since the development of the first-generation vaccines based on outer membrane vesicles (OMV), which were able to contain strain-specific epidemics, but were not suitable for universal use, enormous steps forward in the prevention of Neisseria meningitidis B have been made. The first multicomponent vaccine, Bexsero®, has recently been authorized for use; other vaccines, bivalent rLP2086 and next-generation OMV vaccines, are under development. The new vaccines may substantially contribute to reducing invasive bacterial infections as they could cover most Neisseria meningitidis B strains. Moreover, other potentially effective serogroup B vaccine candidates are being studied in preclinical settings. It is therefore appropriate to review what has recently been achieved in the prevention of disease caused by serogroup B.

Development and validation of the Italian version of the Mobile Application Rating Scale and its generalisability to apps targeting primary prevention.

BackgroundA growing body of literature affirms the usefulness of mobile technologies, including mobile applications (apps), in the primary prevention field. The quality of health apps, which today number in the thousands, is a crucial parameter, as it may affect health-related decision-making and outcomes among app end-users. The mobile application rating scale (MARS) has recently been developed to evaluate the quality of such apps, and has shown good psychometric properties. Since there is no standardised tool for assessing the apps available in Italian app stores, the present study developed and validated an Italian version of MARS in apps targeting primary prevention.MethodsThe original 23-item version of the MARS assesses mobile app quality in four objective quality dimensions (engagement, functionality, aesthetics, information) and one subjective dimension. Validation of this tool involved several steps; the universalist approach to achieving equivalence was adopted. Following two backward translations, a reconciled Italian version of MARS was produced and compared with the original scale. On the basis of sample size estimation, 48 apps from three major app stores were downloaded; the first 5 were used for piloting, while the remaining 43 were used in the main study in order to assess the psychometric properties of the scale. The apps were assessed by two raters, each working independently. The psychometric properties of the final version of the scale was assessed including the inter-rater reliability, internal consistency, convergent, divergent and concurrent validities.ResultsThe intralingual equivalence of the Italian version of the MARS was confirmed by the authors of the original scale. A total of 43 apps targeting primary prevention were tested. The MARS displayed acceptable psychometric properties. The MARS total score showed an excellent level of both inter-rater agreement (intra-class correlation coefficient of .96) and internal consistency (Cronbach’s α of .90 and .91 for the two raters, respectively). Other types of validity, including convergent, divergent, discriminative, known-groups and scalability, were also established.ConclusionsThe Italian version of MARS is a valid and reliable tool for assessing the health-related primary prevention apps available in Italian app stores.

Age-related differences in the accuracy of web query-based predictions of influenza-like illness.

Background Web queries are now widely used for modeling, nowcasting and forecasting influenza-like illness (ILI). However, given that ILI attack rates vary significantly across ages, in terms of both magnitude and timing, little is known about whether the association between ILI morbidity and ILI-related queries is comparable across different age-groups. The present study aimed to investigate features of the association between ILI morbidity and ILI-related query volume from the perspective of age. Methods Since Google Flu Trends is unavailable in Italy, Google Trends was used to identify entry terms that correlated highly with official ILI surveillance data. All-age and age-class-specific modeling was performed by means of linear models with generalized least-square estimation. Hold-out validation was used to quantify prediction accuracy. For purposes of comparison, predictions generated by exponential smoothing were computed. Results Five search terms showed high correlation coefficients of > .6. In comparison with exponential smoothing, the all-age query-based model correctly predicted the peak time and yielded a higher correlation coefficient with observed ILI morbidity (.978 vs. .929). However, query-based prediction of ILI morbidity was associated with a greater error. Age-class-specific query-based models varied significantly in terms of prediction accuracy. In the 0–4 and 25–44-year age-groups, these did well and outperformed exponential smoothing predictions; in the 15–24 and ≥ 65-year age-classes, however, the query-based models were inaccurate and highly overestimated peak height. In all but one age-class, peak timing predicted by the query-based models coincided with observed timing. Conclusions The accuracy of web query-based models in predicting ILI morbidity rates could differ among ages. Greater age-specific detail may be useful in flu query-based studies in order to account for age-specific features of the epidemiology of ILI.

Immunogenicity against Far Eastern and Siberian subtypes of tick-borne encephalitis (TBE) virus elicited by the currently available vaccines based on the European subtype: Systematic review and meta-analysis

Tick-borne encephalitis (TBE) virus, which is usually divided into European, Far Eastern and Siberian subtypes, is a serious public health problem in several European and Asian countries. Vaccination is the most effective measure to prevent TBE; cross-subtype protection elicited by the TBE vaccines is biologically plausible since all TBE virus subtypes are closely related. This manuscript systematically explores available data on the cross-subtype immunogenicity elicited by the currently available Western vaccines based on the European subtype. Completed immunization course of 3 doses of both Western vaccines determined very high seroconversion/seropositivity rates against both Far Eastern and Siberian subtypes among previously flavivirus-naïve subjects. All but one study found no statistically significant difference in titers of neutralizing antibodies against strains belonging to homologous and heterologous subtypes. Pooled analysis of randomized controlled trials on head-to-head comparison of immunogenicity of Western and Russian TBE vaccines did not reveal differences in seroconversion rates against Far Eastern isolates in either hemagglutination inhibition (risk ratio = 0.98, p = 0.83) or enzyme-linked immunosorbent (risk ratio = 0.95, p = 0.44) assays after 2 vaccine doses. This suggests that, in regions where a heterogeneous TBE virus population circulates, vaccines based on the European subtype may be used alongside vaccines based on the Far Eastern subtype. Studies on the field effectiveness of TBE vaccines and investigation of vaccination failures, especially in countries where different subtypes co-circulate, will further elucidate TBE vaccination-induced cross-subtype protection.

Use of different subjective health indicators to assess health inequalities in an urban immigrant population in north-western Italy: a cross-sectional study

BackgroundDespite the steady growth of the immigrant population in Italy, data on the health status of immigrants are scarce. Our main goals were to measure Health-Related Quality of Life (HRQoL), Self-Rated Health (SRH) and morbidity among immigrants in Genoa. We aimed to assess the relative contribution of some social, structural and behavioral determinants to “within-group” health disparities.MethodsWe enrolled 502 subjects by means of snowball sampling. The SF-12 questionnaire, integrated with socio-demographic and health-related items, was used. Multivariate logistic and Poisson regression models were applied in order to identify characteristics associated with poor SRH, lower SF-12 scores and prevalence of self-reported morbidities.ResultsSubjects showed relatively moderate levels of HRQoL (median physical and mental scores of 51.6 and 47.3, respectively) and about 15% of them rated their health as fair or poor. Lower scores in the physical dimension of HRQoL were associated with the presence of morbidities and immigration for work and religious reasons, while those who had migrated for religious and family reasons displayed a lower probability of lower scores in the mental dimension of HRQoL. Poor SRH was associated with female gender, overweight/obesity and presence of morbidities. Moreover, compared with immigrants from countries with a low human development index, immigrants from highly developed societies showed significantly lower odds of reporting poor SRH. About one-third of respondents reported at least one medical condition, while the prevalence of multi-morbidity was 10%. Females, over 45-year-olds, overweight and long-term immigrants had a higher prevalence of medical conditions.ConclusionsOur study confirms the presence of health inequalities within a heterogeneous immigrant population. HRQoL, SRH and morbidity are valid, relatively rapid and cheap tools for measuring health inequalities, though they do so in different ways. These indicators should be used with caution and, if possible, simultaneously, as they could help to identify and to monitor more vulnerable subjects among immigrants.