Systematic review of the efficacy, effectiveness and safety of MF59® adjuvanted seasonal influenza vaccines for the prevention of laboratory-confirmed influenza in individuals ≥18 years of age.

The most effective means of preventing seasonal influenza is through vaccination. In this systematic review, we investigated the efficacy, effectiveness and safety of MF59® adjuvanted trivalent and quadrivalent influenza vaccines to prevent laboratory-confirmed influenza. A systematic literature search was conducted in electronic databases and grey literature sources up to 7 February 2020. Randomised controlled trials and non-randomised studies of interventions (NRSIs) were eligible for inclusion. The search returned 28,846 records, of which 48 studies on MF59® adjuvanted vaccines met our inclusion criteria. No efficacy trials were identified. In terms of vaccine effectiveness (VE), MF59® adjuvanted trivalent influenza vaccines were effective in preventing laboratory-confirmed influenza in older adults (aged ≥65 years) compared with no vaccination (VE = 45%, 95% confidence interval (CI) 23%-61%, 5 NRSIs across 3 influenza seasons). By subtype, significant effect was found for influenza A(H1N1) (VE = 61%, 95% CI 44%-73%) and B (VE = 29%, 95% CI 5%-46%), but not for A(H3N2). In terms of relative VE, there was no significant difference comparing MF59® adjuvanted trivalent vaccines with either non-adjuvanted trivalent or quadrivalent vaccines. Compared with traditional trivalent influenza vaccines, MF59® adjuvanted trivalent influenza vaccines were associated with a greater number of local adverse events (RR = 1.90, 95% CI 1.50-2.39) and systemic reactions (RR = 1.18, 95% CI 1.02-1.38). In conclusion, MF59® adjuvanted trivalent influenza vaccines were found to be more effective than 'no vaccination'. Based on limited data, there was no significant difference comparing the effectiveness of MF59® adjuvanted vaccines with their non-adjuvanted counterparts.

Self-reported diabetes and herpes zoster are associated with a weak humoral response to the seasonal influenza A H1N1 vaccine antigen among the elderly.

BACKGROUND: The immune response to seasonal influenza vaccines decreases with advancing age. Therefore, an adjuvanted inactivated trivalent influenza vaccine (Fluad®) exists for elderly individuals. Fluad® is more immunogenic and efficacious than conventional influenza vaccines. However, the immune response varies and may still result in high frequencies of poor responders. Therefore, we aimed to a) examine the prevalence of a weak response to Fluad® and b) identify potential risk factors. METHODS: A prospective population-based study among individuals 65-80 years old was conducted in 2015/2016 in Hannover, Germany (n = 200). Hemagglutination-inhibition titers 21 days after vaccination with Fluad® served as indicator of vaccine responsiveness. RESULTS: The percentage of vaccinees with an inadequate vaccine response varied depending on the influenza strain: it was lowest for H3N2 (13.5%; 95% CI, 9.4-18.9%), intermediate for B strain (37.0%; 30.6-43.9%), and highest for H1N1 (49.0%; 42.2-55.9%). The risk of a weak response to the influenza A H1N1 strain was independently associated with self-reported diabetes (AOR, 4.64; 95% CI, 1.16-18.54), a history of herpes zoster (2.27; 1.01-5.10) and, to a much lesser extent, increasing age (change per year, 1.08; 0.99-1.16). In addition, herpes zoster was the only risk factor for a weak response to the H3N2 antigen (AOR, 3.12; 1.18-8.23). We found no significant association between sex, Body Mass Index, cancer, hypertension, heart attack and CMV seropositivity and a weak response to these two influenza A antigens. Despite its occurence in over one third of vaccinees, none of the variables examined proved to be risk factors for a weak response to the B antigen. CONCLUSIONS: A considerable proportion of elderly individuals displayed a weak vaccine response to this adjuvanted seasonal influenza vaccine and further efforts are thus needed to improve immune responses to influenza vaccination among the elderly. Diabetes and herpes zoster were identified as potentially modifiable risk factors for a poor vaccine response against influenza A antigens, but the results also reveal the need for broader investigations to identify risk factors for inadequate responses to influenza B antigens. TRIAL REGISTRATION: No. NCT02362919 (ClinicalTrials.gov, date of registration: 09.02.2015).

The Public Health Impact of the So-Called "Fluad Effect" on the 2014/2015 Influenza Vaccination Campaign in Italy: Ethical Implications for Health-Care Workers and Health Communication Practitioners.

Seasonal influenza, causing complications, hospitalizations and deaths, generates a serious socio-economic burden, especially among elderly and high-risk subjects, as well as among adult individuals. Despite the availability and active free-of charge offer of influenza vaccines, vaccine coverage rates remain low and far from the target established by the Ministry of Health. Notwithstanding their effectiveness, vaccines are victims of prejudices and false myths, that contribute to the increasing phenomenon of vaccine hesitancy and loss of confidence. Media and, in particular, new media and information and communication technologies (ICTs) play a major role in disseminating health-related information. They are extremely promising devices for delivering health education and promoting disease prevention, including immunization. However, they can also have a negative impact on population's health attitudes and behaviors when channeling wrong, misleading information. During the 2014/2015 influenza vaccination campaign, the report of four deaths allegedly caused by administration of an adjuvanted influenza vaccine, Fluad - the so-called "Fluad case" - received an important media coverage, which contributed to the failure of the vaccination campaign, dramatically reducing the influenza vaccine uptake. In the extant literature, there is a dearth of information concerning the effect of the "Fluad case". The current study aims at quantifying the impact of the "Fluad effect" at the level of the Local Health Unit 3 (LHU3) ASL3 Genovese, Genoa, Italy. Ethical implications for health-care workers and health communication practitioners are also envisaged.

Enhanced passive safety surveillance of the MF59-adjuvanted quadrivalent influenza vaccine in the elderly during the 2021/22 influenza season.

In accordance with European directives, each year the enhanced safety surveillance (ESS) of seasonal influenza vaccines should be conducted in order to detect any potential increase in reactogenicity when the vaccine composition is updated or a new formulation becomes available. The objective of this passive ESS (EPSS) was to assess the frequency of spontaneously reported adverse events (AEs) following vaccination with the 2021/22 formulation of the MF59-adjuvanted quadrivalent influenza vaccine (aQIV) among older adults in Italy through the collection of data within a short time period (start of seasonal influenza vaccination) in order to monitor the reactogenicity of aQIV early in the season. All AEs reported within seven days following vaccination were analyzed by type and seriousness. In all, 1,059 vaccination cards were distributed to individuals aged ≥65 years. Only one, non-serious, spontaneous individual case safety report was submitted, yielding an overall rate of 0.9 per 1,000 doses administered. This report consisted of a reactogenic AE of pyrexia. The EPSS confirmed that the reactogenicity profile of aQIV was consistent with the known safety profile of the previous trivalent formulation. These optimal safety data could bolster public confidence in influenza vaccination and help to improve vaccination coverage.

Spreading of misinformation on mass media and digital platforms regarding vaccines. A systematic scoping review on stakeholders, policymakers, and sentiments/behavior of Italian consumers.

Studies on traditional and social media have found that misinformation about vaccines has been widely spread over the last decade, negatively impacting public opinion and people's willingness to get vaccinated. We reviewed the sentiments of Italian users to define the characteristic of anti-vax and pro-vax contents and defined the strategies to deal with the misinformation. Scopus, MEDLINE/PubMed, Google Scholar (up to page 10), and ISI Web of Knowledge databases were systematically searched. Research articles, brief reports, commentaries, and letters published between January 1, 2010 and March 30, 2022 were included in the search. No-vax or ambiguous contents in Italian mass media are not prevalent compared to neutral and pro-vax content; the communication of no-vax groups is significantly simplified, favoring the understanding of the topics by users. Events related to vaccinations are associated with news coverage by media, search engine consultations, and user reactions on social networks. In this context, the activity of no-vax groups is triggered, and misinformation and fake news spread even further. A multifactorial approach is necessary to manage online user sentiment and use mass and social media as health promotion tools.

Immunogenicity and safety of MF59-adjuvanted quadrivalent influenza vaccine versus standard and alternate B strain MF59-adjuvanted trivalent influenza vaccines in older adults.

OBJECTIVE: Evaluate whether adjuvanted quadrivalent influenza vaccine (aQIV) elicits a noninferior immune response compared with a licensed adjuvanted trivalent influenza vaccine (aTIV-1; Fluad™) and aTIV-2 containing an alternate B strain, examine whether aQIV had immunological superiority for the B strain absent from aTIV comparators, and evaluate reactogenicity and safety among adults ≥65 years. METHODS: In a multicenter, double-blind, randomized controlled trial, adults ≥65 years were randomized 2:1:1 to vaccination with aQIV (n = 889), aTIV-1 (n = 445), or aTIV-2 (n = 444) during the 2017-2018 influenza season. Immunogenicity was assessed by hemagglutination inhibition (HI) assay conducted on serum samples collected before vaccination and 21 days after vaccination for homologous influenza strains. RESULTS: aQIV met non-inferiority criteria for geometric mean titer ratios (GMT ratios) and seroconversion rate (SCR) differences against aTIV. The upper bounds of the 2-sided 95% confidence interval (CI) for GMT ratios were <1.5 for all 4 strains (A/H1N1 = 1.27, A/H3N2 = 1.09, B-Yamagata = 1.08, B-Victoria = 1.08). The upper bounds of the 95% CI of the SCR differences were <10% for all 4 strains (A/H1N1 = 7.76%, A/H3N2 = 4.96%, B-Yamagata = 3.27%, B-Victoria = 2.55%). aQIV also met superiority criteria (upper bound of 95% CI for GMT ratios <1 and SCR differences <0) for B strain absent from aTIV comparators (B-Yamagata GMT ratio = 0.70, SCR difference = -8.81%; B-Victoria GMT ratio = 0.78, SCR difference = -8.11%). aQIV and aTIV vaccines were immunogenic and well-tolerated. The immunological benefit of aQIV was also demonstrated in age subgroups 65-74 years, 75-84 years, and ≥85 years and in those with high comorbidity risk scores. Reactogenicity profiles were generally comparable. CONCLUSION: aQIV induces a similar immune response as the licensed aTIV vaccine against homologous influenza strains and has a comparable reactogenicity and safety profile. Superior immunogenicity against the additional B strain was observed, indicating that aQIV could provide a broader protection than aTIV against influenza in older adults (NCT03314662).

Enhanced Passive Safety Surveillance (EPSS) confirms an optimal safety profile of the use of MF59® -adjuvanted influenza vaccine in older adults: Results from three consecutive seasons.

BACKGROUND: In Europe, the enhanced safety surveillance (ESS) of seasonal influenza vaccines is mandatory, in order to detect any potential increase in reactogenicity when the vaccine composition is updated. The MF59® -adjuvanted influenza vaccine (Fluad™) is the first and the only licensed adjuvanted seasonal influenza vaccine in Europe. OBJECTIVE: Our objective was to summarize the safety data of Fluad™ over three consecutive seasons. METHODS: A passive approach to ESS (EPSS) was adopted, in which reporting of spontaneous adverse events (AEs) by vaccinees and vaccine exposure was estimated, in order to generate a near real-time reporting rate. EPSS was conducted in Italy during the 2015, 2016, and 2017 influenza seasons in the primary care setting. All AEs reported within 7 days following immunization were analyzed by season, type and seriousness. Fisher's exact test was used to compare frequencies between seasons. RESULTS: Total exposure accounted for approximately 1,000 doses of Fluad™ for each season. A total of 0.5% (2015), 0.7% (2016), and 0.5% (2017) individual case safety reports (ICSRs) were received, corresponding to a total of 9 (2015), 18 (2016), and 12 (2017) spontaneous AEs. The frequencies of AEs of interest were below those expected on the basis of the known safety profile of the vaccine. Most AEs were mild-to-moderate in severity. No between-season difference was found. CONCLUSIONS: Our analyses confirmed that the safety data observed were consistent with the known safety profile of Fluad™, which has been amply established over the last 20 years. No significant changes in the safety profile were observed.

Post-licensure surveillance of trivalent adjuvanted influenza vaccine (aIIV3; Fluad), Vaccine Adverse Event Reporting System (VAERS), United States, July 2016-June 2018.

BACKGROUND: Trivalent adjuvanted influenza vaccine (aIIV3; Fluad®) was approved in the United States (U.S.) in 2015 for adults aged ≥65 years and has been in use since the 2016-17 influenza season. METHODS: We analyzed U.S. reports for aIIV3 submitted from July 1, 2016 through June 30, 2018 to the Vaccine Adverse Event Reporting System (VAERS), a national spontaneous reporting system. Medical records were reviewed for serious reports. Among individuals ≥65 years of age, the relative frequency of the most commonly reported adverse events (AEs) after aIIV3 were compared with non-adjuvanted inactivated influenza vaccines given to adults aged ≥65 years, high-dose trivalent influenza vaccine (IIV3-HD) and trivalent or quadrivalent vaccines (IIV3/IIV4). Data mining analyses were undertaken to identify whether AEs for aIIV3 occurred disproportionately more than expected compared to all influenza vaccines. RESULTS: VAERS received 630 reports after aIIV3, of which 521 (83%) were in adults aged ≥65 years; 79 (13%) in persons <65 years and in 30 (5%) reports age was missing; 19 (3%) reports were serious, including two deaths (0.4%) related to myocardial infarction and Sjogren's syndrome. The most common AEs reported in adults aged ≥65 years were injection site pain (21%) and erythema (18%), with similar proportions reported for IIV3-HD (17% and 19%, respectively) and for IIV3/IIV4 (15%, each). Except for reports related to vaccination of inappropriate age (n = 79) and syringe malfunction (n = 6), data mining did not identify other disproportionately reported AEs. CONCLUSIONS: Although our review of aIIV3 in VAERS did not identify any unexpected health conditions of concern, we observed more than twice the expected number of reports with administration of the vaccine to persons outside of the age range for which the vaccine is approved in the U.S. Health care providers should be educated on the age groups for whom aIIV3 is recommended.

An infodemiological investigation of the so-called "Fluad effect" during the 2014/2015 influenza vaccination campaign in Italy: Ethical and historical implications.

Influenza vaccines represent a major tool to contain the clinical and epidemiological burden generated by influenza. However, in spite of their effectiveness, vaccines are victims of prejudices and false myths, which contribute to the increasing phenomenon of vaccine hesitancy and loss of confidence. Media and, mainly, new media, and information and communication technologies play a major role in disseminating health-related information. While, on the one hand, they can be extremely promising in promoting disease prevention, on the other hand, they can also have a negative impact on population's health attitudes and behaviors when delivering information not based on scientific evidences. The "Fluad-case" is an excellent example of the crucial role of an adequate information campaign. Following the cluster of deaths allegedly related to the administration of the adjuvanted influenza vaccine "Fluad" during the 2014-2015 influenza campaign, the Italian health authorities and regulatory bodies decided the withdrawal of two potentially contaminated Fluad batches. This fostered a huge media coverage, with resulted in negatively impacting on influenza vaccination coverage. Monitoring and tracking the Fluad-related web searches, we showed that Liguria resulted the Italian region with the highest number of Fluad-related website searches and that, interestingly, Fluad was searched also in Regions in which this vaccine was not distributed. A positive moderate correlation between accessing Fluad-related websites and overall influenza vaccination coverage was found (r = 0.66 ([95%CI 0.29-0.86], p = 0.0026). Considering subjects ≥65 years, who are the subjects for which the Fluad vaccination is recommended, the correlation resulted r = 0.49 ([95%CI 0.03-0.78], p = 0.0397). As such, health authorities and decision-makers should promote high-quality communication campaigns in order to raise awareness of vaccination practices.

Frequencies of peripheral immune cells in older adults following seasonal influenza vaccination with an adjuvanted vaccine.

As age increases, immune responses and consequently protection following vaccination to seasonal influenza is commonly believed to decrease. Possible drivers of this immune dysfunction include immunosenescence, repeated exposure to the same seasonal influenza antigens, and prior infection with cytomegalovirus (CMV). Here, to determine immune parameters distinguishing vaccine humoral responders (R) from non-responders (NR) following vaccination, we surveyed broad peripheral blood "cellular immune correlates" of older adults vaccinated with Fluad® (an adjuvanted subunit influenza vaccine containing strains H1N1, H3N2 and B). Phenotyping included αß-T-cells, γδ-T-cells, B-cells and myeloid cells. The frequencies of most of these lymphocyte phenotypes were found to be similar in R and NR, although perhaps counterintuitively, one of the few differences seen between the two groups was higher frequencies of regulatory T-cells in R. These differences were more prominent for responses to the vaccine strains H1N1 and H3N2 than to the B strain, and in CMV-seropositive than CMV-seronegative elderly. Further, frequencies of early-differentiated CD4+ T-cells tended to be higher and frequencies of memory CD4+ T-cells tended to be lower in R than NR. There were also differences in B-cells, with higher frequencies in R compared to NR. To the best of our knowledge, these results are the first to report such differences in elderly people responding or failing to respond to adjuvanted seasonal influenza vaccination.

The "Fluad Case" in Italy: Could it have been dealt differently?

During the influenza vaccination campaign 2014-2015, the reporting of 3 deaths within 48 hours of vaccination with Fluad brought the Italian Medicines Agency (AIFA) to pronounce the withdrawal of 2 batches of vaccine, based on the precautionary principle. Investigations by the Italian National Institute of Health, and by the Pharmacovigilance Risk Assessment Committee (PRAC), the committee at the European Medicines Agency (EMA) responsible for monitoring and assessing the safety profiles of human drugs, concluded that there was a lack of causality between the reported deaths and the vaccines administered. However, the media impact of the decision taken by AIFA, resulted in a lower influenza vaccination coverage compared with the previous years. The aim of our study was to identify possible critical points that may have led to a non-perfect management of the event. A review of the regulatory framework in place was performed, with a particular focus on the Guidelines on Good Pharmacovigilance Practices developed by the EMA to facilitate the signal management process. The management of reports involves the following steps: signal detection, its validation and confirmation, analysis and prioritization, assessment, recommendations for action and the exchange of information. In our opinion, both the signal detection phase and the phase of validation have been critical: the withdrawal of vaccine batches is possible even in case of a single suspected serious adverse reaction. However, aspects such as the biological plausibility, the presence of potential alternative causes and previous awareness should also be considered. Furthermore, the number of reported deaths was consistent with the expected background mortality rate in the vaccinated cohort. The disproportionate media coverage given to the AIFA decision resulted in a reduced vaccine confidence in the general population and in a decreased immunization coverage. Improving the communication on vaccine safety issues is crucial at this stage to restore a climate of trust in this powerful tool for primary prevention.

Drug Information Association (DIA) - 52nd Annual Meeting (June 26-30, 2016 - Philadelphia, Pennsylvania, USA).

The Drug Information Association's Annual Meeting is the largest global event which crosses all disciplines involved in the discovery development and life cycle management of healthcare products. The 2016 meeting, its 52nd occurrence, brought experts from regulatory and government agencies, industry, academia and health and patient organizations together to discuss novel therapies in development and how to use these to enhance health and well-being in patient groups, with the hope of increasing knowledge across all areas involved.

Adverse events following immunization: is this time for the use of WHO causality assessment?

In recent years, public health authorities in industrialized countries have noted an increase in the numbers of parents choosing not to have their children vaccinated and in the activities of 'antivaccination' movements. Doubts about vaccine safety and lack of surveillance of adverse events following immunization (AEFI) are the most frequent themes proposed by antivaccination movements. This editorial aims to critically analyze the use of AEFI assessment procedures among national health authorities and public health researchers. In fact, the WHO recommended and published a systematic and standardized causality assessment process for serious AEFI, providing a method for individual causality assessment to be used by staff of national immunization programs, regulatory authorities and pharmacovigilance or surveillance departments. The last update was published in March 2013 but to date, an Internet search reveals no information or reports on AEFI surveillance that uses the WHO AEFI causality assessment.

Hemozoin is a potent adjuvant for hemagglutinin split vaccine without pyrogenicity in ferrets.

BACKGROUND: Synthetic hemozoin (sHZ, also known as ß-hematin) from monomeric heme is a particle adjuvant which activates antigen-presenting cells (APCs), such as dendritic cells and macrophages, and enhances humoral immune responses to several antigens, including ovalbumin, human serum albumin, and serine repeat antigen 36 of Plasmodium falciparum. In the present study, we evaluated the adjuvanticity and pyrogenicity of sHZ as an adjuvant for seasonal trivalent hemagglutinin split vaccine (SV) for humans using the experimental ferret model. METHOD: Ferrets were twice immunized with trivalent SV, SV with sHZ (SV/sHZ) or Fluad, composed of trivalent SV with MF59. Serum hemagglutination inhibition (HI) titers against three viral hemagglutinin (HA) antigens were measured at every week after the immunization. The pyrogenicity of SV/sHZ was examined by monitoring the body temperature of the immunized ferrets. To evaluate the protective efficacy of SV/sHZ, the immunized ferrets were challenged with influenza virus B infection, followed by measurement of viral titers in the nasal cavity and body temperature. RESULTS: sHZ enhanced HI titers against three viral HA antigens in a dose-dependent manner, to an extent comparable to that of Fluad. The highest dose of sHZ (800 µg) immunized with SV conferred sterile protection against infection with heterologous Influenza B virus, without causing any pyrogenic reaction such as high fever. CONCLUSION: In the present study, sHZ enhanced the protective efficacy of SV against influenza infection without inducing pyrogenic reaction, suggesting sHZ to be a promising adjuvant candidate for human SV.

Enhanced and persistent antibody response against homologous and heterologous strains elicited by a MF59-adjuvanted influenza vaccine in infants and young children.

BACKGROUND: Non-adjuvanted seasonal influenza vaccines show only modest efficacy in young children. This study compared the immunogenicity, reactogenicity and safety of the MF59-adjuvanted trivalent subunit vaccine (aTIV) with two non-adjuvanted trivalent vaccines, TIV-1, the non-adjuvanted version of aTIV, and TIV-2, a split virion vaccine. METHODS: 6078 children received two doses of aTIV (n=3125), TIV-1 (n=1479), or TIV-2 (n=1474) four weeks apart (Days 1 and 29). Children aged 6 to <36 months and 36 to <72 months received 0.25 mL and 0.50 mL doses, respectively. Immunogenicity was assessed by hemagglutination inhibition (HI) assay (n=2435) on Days 1, 29, 50 and 209. Safety was assessed up to Day 394. RESULTS: After the second vaccination (Day 50), the aTIV group showed significantly higher geometric mean HI titers and seroconversion rates than the TIV-1 or TIV-2 groups against all homologous and heterologous strains. The difference was enhanced at HI titers ≥110. aTIV elicited a faster, more persistent antibody response, with significantly higher titers in the aTIV group after one vaccination (Day 29) and after six months (Day 209) than in either TIV group. aTIV was more reactogenic than were TIV-1 and TIV-2 but rates of severe adverse events were very low for all three vaccines. CONCLUSION: In infants and young children, the MF59-adjuvanted vaccine induced substantially faster (after one dose), higher, persistent HI titers than the non-adjuvanted vaccines, with consistently higher seroprotection rates at increased threshold HI titers. This trial is registered at clinicaltrials.gov: NCT01346592.