CORRELATES OF PROTECTION AND HOST-RELATED MODIFIERS OF THE IMMUNOGENICITY OF INFLUENZA VACCINES: EVIDENCE MAPS AND EVIDENCE GAPS

Seasonal influenza is the leading infectious disease in terms of its health and socioeconomic impact. Annual immunization is the most efficient way to reduce this burden. To be clinically effective, influenza vaccines must be immunogenic, and several immunological assays to test their immunogenicity have been developed. The overall aim of this PhD thesis is to provide the principal stakeholders (including scientists, healthcare professionals, policy-makers, pharmaceutical industry, etc.) with stateof-the-art knowledge and practices related to influenza vaccine-induced immunogenicity. To achieve this aim, we developed a novel empirical approach that incorporated some modern techniques, including, for example, evidence mapping. Basically, this thesis is composed of three main domains. In the introductory part, we will briefly cover the topics of influenza disease, influenza vaccination, the immunogenicity measurements of influenza vaccines and their correlates of protection. The second part, which is the core of the present project, is composed of two original case studies. The first study aimed to describe the patterns of use of the various immunological assays available to measure the influenza vaccine-induced adaptive immune response and to determine its correlates of protection. For this purpose, we analyzed 1,164 phase I–IV studies that enrolled a total of 754,935 subjects. Of the studies included in our analysis, 76.5% measured only the humoral immune response. Among these, the hemagglutination-inhibition assay was by far the most widely used. Other, less common, humoral immune response assays were: virus neutralization (21.7%), enzyme-linked immunosorbent (10.1%), single radial hemolysis (4.6%) and assays able to quantify antineuraminidase antibodies (1.7%). By contrast, cell-mediated immunity was quantified in only 23.5% of studies. Several variables were significantly (P < .05) associated with the use of single assays. Specifically, some influenza vaccine types (e.g. adjuvanted, live attenuated and cell culture-derived or recombinant), study phase and study sponsorship pattern were usually found to be statistically significant predictors. In the second study, we went further by systematically analyzing host-related factors able to modify influenza vaccine-induced immunogenicity. To this end, a total of 28 systematic reviews/meta-analyses (with thousands of participants) were analyzed. These covered the following domains: intravenous drug use, psychological stress, acute and chronic physical exercise, genetic polymorphisms, use of pre-/pro-/symbiotics, previous Bacillus Calmette–Guérin vaccination, diabetes mellitus, vitamin D supplementation/deficiency, latent cytomegalovirus infection and various forms of immunosuppression. In order to present effect sizes on the same scale, all meta-analyses were re-performed, whenever possible, and cumulative evidence synthesis ranking was carried out. Meta-analysis was conducted separately on each health condition category and virus (sub)type. A total of 295 meta-analyses were re-performed/performed ex novo; of these, 97 pooled estimates were used in order to construct an evidence-based stakeholder-friendly map. Finally, we discussed the principal findings, made some suggestions from the point of view of the various stakeholders and proposed a novel immunogenicity pathway

Evaluation of maternal perception of children's weight and Body Mass Index in Tuscany, Italy

Background: The prevention of overweight is a high-priority public health task. The perception that parents have of their children’s nutritional status is a well recognized risk factor for obesity in children, so the aim of our study was to evaluate mothers’ perceptions of their children’s nutritional status. Methods: We conducted, in 2016, a cross-sectional study enrolling1710 children (third grade of all primary schools ) in Tuscany, as well as their mothers. Mothers’ information were collected through a self-administered questionnaire, while children (weighed and measured) filled a questionnaire under the supervision of qualified personnel. Results: 1449 children completed the questionnaire. 74.12% of mothers were able to correctly identify children BMI. The non correct classification tends to significantly decrease in presence of a high educational level compared to low educational level. Mothers’ BMI seems to not be associated with misclassification. The non correct classification was significantly associated with mothers’ opinion about their children’s eating habit. Conclusion: Our data confirmed that, in Tuscany, a limited percentage of mothers tend to misclassify the nutritional state of their children, but in order to maintain these encouraging results, further efforts should be done in order to make all mothers able to correctly evaluate their children. Statements:Authors declare no conflict of interest. The study was conducted according to the criteria set by the declaration of Helsinki and each subject signed an informed consent before participating to the study. Approval of the protocol was obtained from the institutional review board of the National Institute of Health, including the use of opt-out consent; that is, parents could refuse participation but the lack of a returned form was taken to imply consent to their child’s participation

Surveillance of Influenza and Other Airborne Transmission Viruses during the 2021/2022 Season in Hospitalized Subjects in Tuscany, Italy

Winter in the northern hemisphere is characterized by the circulation of influenza viruses, which cause seasonal epidemics, generally from October to April. Each influenza season has its own pattern, which differs from one year to the next in terms of the first influenza case notification, the period of highest incidence, and the predominant influenza virus subtypes. After the total absence of influenza viruses in the 2020/2021 season, cases of influenza were again recorded in the 2021/2022 season, although they remained below the seasonal average. Moreover, the co-circulation of the influenza virus and the SARS-CoV-2 pandemic virus was also reported. In the context of the DRIVE study, oropharyngeal swabs were collected from 129 Tuscan adults hospitalized for severe acute respiratory infection (SARI) and analyzed by means of real-time polymerase chain reaction (RT-PCR) for SARS-CoV-2 and 21 different airborne pathogens, including influenza viruses. In total, 55 subjects tested positive for COVID-19, 9 tested positive for influenza, and 3 tested positive for both SARS-CoV-2 and the A/H3N2 influenza virus. The co-circulation of different viruses in the population requires strengthened surveillance that is no longer restricted to the winter months. Indeed, constant, year-long monitoring of the trends of these viruses is needed, especially in at-risk groups and elderly people

Egg-Independent Influenza Vaccines and Vaccine Candidates

Vaccination remains the principal way to control seasonal infections and is the most effective method of reducing influenza-associated morbidity and mortality. Since the 1940s, the main method of producing influenza vaccines has been an egg-based production process. However, in the event of a pandemic, this method has a significant limitation, as the time lag from strain isolation to final dose formulation and validation is six months. Indeed, production in eggs is a relatively slow process and production yields are both unpredictable and highly variable from strain to strain. In particular, if the next influenza pandemic were to arise from an avian influenza virus, and thus reduce the egg-laying hen population, there would be a shortage of embryonated eggs available for vaccine manufacturing. Although the production of egg-derived vaccines will continue, new technological developments have generated a cell-culture-based influenza vaccine and other more recent platforms, such as synthetic influenza vaccines

Trend of Correlations between Psychological Symptoms and Socioeconomic Inequalities among Italian Adolescents: Cross-Sectional Study from 2006 to 2018 in Tuscany Region

Abstract: Adolescence is a critical moment in life; people become individuals, create new relationships, develop social skills and learn behaviours that they will use for the rest of their lives. During this phase, adolescents establish patterns of behaviour that can protect their health. This study aims to 1. assess the presence of psychological disorders in adolescents of both genders, 2. determine their relation to socio-economic differences based on the Family Affluence Scale (FAS), and 3. assess trends from 2006 to 2018. Data were collected from the Italian Health Behaviour in School-aged Children survey given to a representative sample of Tuscan adolescents aged 11–15 years. Participants (n. 12,550) filled out questionnaires to assess whether psychological symptoms such as feeling low, irritability, nervousness, or sleeping difficulties manifested weekly or more often over the past six months. For the study we utilized a cross-sectional survey method and linear regression to examine the association between psychological symptoms (dependent variable measured on an interval scale (0–16)), gender and FAS. We conducted similar analyses using logistic regressions for each of the four symptoms. An increase in psychological symptoms in both genders was revealed between 2006 and 2018, with a statistically significant presence in females: 0.29 (95% Confidence Interval [CI], 0.17 to 0.41), 1.43 (95% CI, 1.37 to 1.48) and 1.43 (95% CI, 1.34 to 1.52) in low-, medium- and high-affluence families, respectively; whereas males presented 0.14 (95% CI, 0.01 to 0.27), 0.71 (95% CI, 0.65 to 0.77) and 0.31 (95% CI, 0.22 to 0.39), respectively. The probability of a predictive episode of psychological symptoms (feeling low, irritability, nervousness, sleeping difficulties) occurring weekly, or more, often was greatly increased in females of all socioeconomic classes. These findings suggest that the increase in psychological disorders in adolescents should be considered a public health problem and further investigated through longitudinal studies and continuous monitoring of health trends

Medicine use and recurrent complaints among 15-years-old adolescents in Tuscany

Background.  The  use  of  medicines  to  treat  common  complaints,  such  as  headache, stomachache, difficulty in getting to sleep and nervousness, is widespread among ado-lescents,  and  is  increasing.  The  aim  of  this  survey  was  to  estimate  the  prevalence  of recurrent specific complaints among 15-year-old adolescents in Tuscany over three years(2006, 2010 and 2014) and that of medicine use to treat these complaints among boysand girls.Methods.The present study  is based on data from the Tuscan HBSC studies at threetime points (2006, 2010 and 2014), which involved 2830 adolescents, aged 15 years old(1395 boys and 1435 girls).Results.Overall, the data confirm that adolescents who suffer from recurrent complaintsare more likely to use medicines. The prevalence rates of all complaints were higher ingirls than in boys in the three years considered. Over the whole period, headache, stom-achache and difficulty in getting to sleep increased in girls, while boys displayed signifi-cant decrease in nervousness and stomachache.Conclusion.Our findings underline the fact that the use of medicines in adolescence isa public health concern and constitutes an emerging issue that needs greater attentionand investigation on the part of scientific researchBackground. The use of medicines to treat common complaints, such as headache, stomachache, difficulty in getting to sleep and nervousness, is widespread among adolescents, and is increasing. The aim of this survey was to estimate the prevalence of recurrent specific complaints among 15-year-old adolescents in Tuscany over three years (2006, 2010 and 2014) and that of medicine use to treat these complaints Conclusion. Our findings underline the fact that the use of medicines in adolescence is a public health concern and constitutes an emerging issue that needs greater attention and investigation on the part of scientific research

Influenza D virus: a potential threat for humans?

Influenza D virus (IDV) is a novel influenza virus first isolated from swine in 2011 in Oklahoma. Several studies have isolated IDV in cattle from multiple geographic areas, suggesting that cattle could be a possible primary natural reservoir for the virus. To date, few studies have been performed on human samples and there is no conclusive evidence that IDV has the ability to infect humans. This serological study aimed to assess the prevalence of antibodies against IDV in the human population. The IDV used in the serological analysis was influenza D/bovine/Oklahoma/660/2013. The human serum samples, collected in Italy between 2005 and 2017, were randomly selected from the laboratory serum bank and tested by the haemagglutination inhibition (HI) assay. HI positivity has been confirmed using the virus neutralization (VN) assay. Based on HI positivity (HI titers ≥ 10), a low prevalence (5%–10%) was observed between 2005 and 2007. There has been a sharp increase since 2008, resulting in two main peaks in 2009–2010 and 2013–2014, a finding confirmed by the statistical trend analysis. The same pattern and trends can be seen with higher HI titers of >20 and ≥40. The prevalence of antibodies against IDV has increased in the human population in Italy from 2005 to 2017. Low prevalence values between 2005 and 2007 suggest that IDV most probably circulated before its detection in 2011, and perhaps even before 2005. In Italy, IDV has been shown to circulate among swine and bovine herds. It is, therefore, possible that prevalence peaks in humans follow the infection epidemics in animals and do not to persist in the population, resembling a spillover event from the animal reservoir and showing that the virus may not circulate consistently in the human population. However, IDV seemed to have the ability to elicit an immune response in humans

No evidence of SARS-CoV-2 in hospitalized patients with severe acute respiratory syndrome in five Italian hospitals from 1st November 2019 to 29th February 2020

Background On 9th January 2020, China CDC reported a novel coronavirus (later named SARS-CoV-2) as the causative agent of the coronavirus disease 2019 (COVID-19). Identifying the first appearance of virus is of epidemiological importance to tracking and mapping the spread of SARS-CoV-2 in a country. We therefore conducted a retrospective observational study to detect SARS-CoV-2 in oropharyngeal samples collected from hospitalized patients with a Severe Acute Respiratory Infection (SARI) enrolled in the DRIVE (Development of Robust and Innovative Vaccine Effectiveness) study in five Italian hospitals (CIRI-IT BIVE hospitals network) (1st November 2019 – 29th February 2020). Objectives To acquire new information on the real trend in SARS-CoV-2 infection during pandemic phase I and to determine the possible early appearance of the virus in Italy. Materials and methods Samples were tested for influenza [RT-PCR assay (A/H1N1, A/H3N2, B/Yam, B/Vic)] in accordance with the DRIVE study protocol. Subsequently, swabs underwent molecular testing for SARS-COV-2. [one-step real-time multiplex retro-transcription (RT) PCR]. Results In the 1683 samples collected, no evidence of SARS-CoV-2 was found. Moreover, 28.3% (477/1683) of swabs were positive for influenza viruses, the majority being type A (358 vs 119 type B). A/H3N2 was predominant among influenza A viruses (55%); among influenza B viruses, B/Victoria was prevalent. The highest influenza incidence rate was reported in patients aged 0–17 years (40.3%) followed by those aged 18–64 years (24.4%) and ≥65 years (14.8%). Conclusions In Italy, some studies have shown the early circulation of SARS-CoV-2 in northern regions, those most severely affected during phase I of the pandemic. In central and southern regions, by contrast no early circulation of the virus was registered. These results are in line with ours. These findings highlight the need to continue to carry out retrospective studies, in order to understand the epidemiology of the novel coronavirus, to better identify the clinical characteristics of COVID-19 in comparison with other acute respiratory illnesses (ARI), and to evaluate the real burden of COVID-19 on the healthcare system

Normal and pathogenic variation of RFC1 repeat expansions: implications for clinical diagnosis

Cerebellar Ataxia, Neuropathy and Vestibular Areflexia Syndrome (CANVAS) is an autosomal recessive neurodegenerative disease, usually caused by biallelic AAGGG repeat expansions in RFC1. In this study, we leveraged whole genome sequencing (WGS) data from nearly 10,000 individuals recruited within the Genomics England sequencing project to investigate the normal and pathogenic variation of the RFC1 repeat. We identified three novel repeat motifs, AGGGC (n=6 from 5 families), AAGGC (n=2 from 1 family), AGAGG (n=1), associated with CANVAS in the homozygous or compound heterozygous state with the common pathogenic AAGGG expansion. While AAAAG, AAAGGG and AAGAG expansions appear to be benign, here we show a pathogenic role for large AAAGG repeat configuration expansions (n=5). Long read sequencing was used to fully characterise the entire repeat sequence and revealed a pure AGGGC expansion in six patients, whereas the other patients presented complex motifs with AAGGG or AAAGG interruptions. All pathogenic motifs seem to have arisen from a common haplotype and are predicted to form highly stable G quadruplexes, which have been previously demonstrated to affect gene transcription in other conditions. The assessment of these novel configurations is warranted in CANVAS patients with negative or inconclusive genetic testing. Particular attention should be paid to carriers of compound AAGGG/AAAGG expansions, since the AAAGG motif when very large (>500 repeats) or in the presence of AAGGG interruptions. Accurate sizing and full sequencing of the satellite repeat with long read is recommended in clinically selected cases, in order to achieve an accurate molecular diagnosis and counsel patients and their families