Annual public health and economic benefits of seasonal influenza vaccination: a European estimate

An oleanic acid decorated gold nanorod for highly efficient inhibition of hemagglutinin and visible rapid detection of the influenza virus

Accurate diagnosis and effective antiviral treatments are urgently needed for the prevention and control of flu caused by influenza viruses. In this study, a novel oleanic acid (OA) functionalized gold nanorod OA-AuNP was prepared through a convenient ligand-exchange reaction. As hemagglutinin (HA) on the viral surface binds strongly to the multiple OA molecules on the surface of the nanoparticle, the prepared OA-AuNP was found to exhibit potent antiviral activity against a wide range of influenza A virus strains. Furthermore, the change in color resulting from the specific binding between HA and OA and the resultant aggregation of the OA-AuNP can be visually observed or measured by UV-vis spectra with a detection limit of 2 and 0.18 hemagglutination units (HAU), respectively, which is comparable to the commercially available influenza colloid gold rapid diagnostic kits. These findings demonstrate the potential of the OA-AuNP for the development of novel multivalent antiviral conjugates and the diagnosis of influenza virus.

Public health and economic benefits of seasonal influenza vaccination in risk groups in France, Italy, Spain and the UK: state of play and perspectives

BACKGROUND

Seasonal influenza epidemics have a substantial public health and economic burden, which can be alleviated through vaccination. The World Health Organization (WHO) recommends a 75% vaccination coverage rate (VCR) in: older adults (aged ≥ 65 years), individuals with chronic conditions, pregnant women, children aged 6-24 months and healthcare workers. However, no European country achieves this target in all risk groups. In this study, potential public health and economic benefits achieved by reaching 75% influenza VCR was estimated in risk groups across four European countries: France, Italy, Spain, and the UK.

METHODS

A static epidemiological model was used to estimate the averted public health and economic burden of increasing the 2021/2022 season VCR to 75%, using the efficacy data of standard-dose quadrivalent influenza vaccine. For each country and risk group, the most recent data on population size, VCR, pre-pandemic influenza epidemiology, direct medical costs and absenteeism were identified through a systematic literature review, supplemented by manual searching. Outcomes were: averted influenza cases, general practitioner (GP) visits, hospitalisations, case fatalities, number of days of work lost, direct medical costs and absenteeism-related costs.

RESULTS

As of the 2021/2022 season, the UK achieved the highest weighted VCR across risk groups (65%), followed by Spain (47%), France (44%) and Italy (44%). Based on modelling, the 2021/2022 VCR prevented an estimated 1.9 million influenza cases, avoiding 375,200 GP visits, 73,200 hospitalisations and 38,400 deaths. To achieve the WHO 75% VCR target, an additional 24 million at-risk individuals would need to be vaccinated, most of which being older adults and patients with chronic conditions. It was estimated that this could avoid a further 918,200 influenza cases, 332,000 GP visits, 16,300 hospitalisations and 6,300 deaths across the four countries, with older adults accounting for 52% of hospitalisations and 80% of deaths. An additional €84 million in direct medical costs and €79 million in absenteeism costs would be saved in total, with most economic benefits delivered in France.

CONCLUSIONS

Older adults represent most vaccine-preventable influenza cases and deaths, followed by individuals with chronic conditions. Health authorities should prioritise vaccinating these populations for maximum public health and economic benefits.

Understanding the gap between guidelines and influenza vaccination coverage in people with diabetes: a scoping review

Background

Diabetes affects millions of people worldwide, making them more vulnerable to infections, including seasonal influenza. It is therefore particularly important for those suffering from diabetes to be vaccinated against influenza each year. However, influenza vaccination coverage remains low in this population. This review primarily aims to identify the determinants of influenza vaccination in people with diabetes (T1D or T2D). Secondly, it aims to assess main recommendations for influenza vaccination, vaccine effectiveness, vaccination coverage, and how education and pharmacists can encourage uptake of the vaccine in the diabetic population.

Methods

A scoping review was conducted in January 2022 to systematically review evidence on influenza vaccination in people with diabetes using data from PubMed, Science Direct, and EM Premium with terms such as "Diabetes mellitus," "Immunization Programs," "Vaccination," and "Influenza Vaccines." Quality assessment and data extraction were independently conducted by two authors. Disagreements between the authors were resolved through discussion and consensus, and if necessary, by consulting a third author.

Results

Of the 333 records identified, 55 studies met the eligibility criteria for inclusion in this review. Influenza vaccination was recommended for people ≥6 months. Despite effectiveness evidence showing a reduction in mortality and hospitalizations in people with diabetes vaccinated vs. non-vaccinated ones, very few studies reported a coverage rate ≥ 75%, which is WHO's target objective. Determinants such as advanced age, presence of comorbidities and healthcare givers' advice were associated with increased vaccination uptake. On the contrary, fear of adverse reactions and concerns about vaccine effectiveness were significant barriers. Finally, education and pharmacists' intervention played a key role in promoting vaccination and increasing vaccination uptake.

Conclusion

Influenza vaccination coverage in people with diabetes remains low despite recommendations and evidence on vaccine effectiveness. Motivators and barriers as well as several socio-demographic and clinical factors have been identified to explain this trend. Efforts are now needed to increase the number of diabetics vaccinated against influenza, mainly through education and the involvement of healthcare givers.

High uptake of COVID-19 vaccines among healthcare workers in urban Uganda

OBJECTIVES

The aim of the study was to describe the facilitators, barriers to and level of uptake of COVID-19 vaccines among healthcare workers in primary healthcare facilities in an urban setting in Uganda.

MATERIALS AND METHODS

We conducted a cross-sectional study among HCWs in private and public health facilities in Entebbe municipality between July 2021 and August 2021. Data was collected using a structured questionnaire that was shared, via an online link, to consented participants. Uptake of the vaccines among healthcare workers was analysed as proportions, and logistic regression was used to analyse barriers and facilitators to uptake of COVID-19 vaccines.

RESULTS

The study enrolled 360 participants, with 61.7% (n = 222) females. A total of 236 (65.6%) healthcare workers had received at least one dose of COVID-19 vaccine, with higher uptake among females 64% (n = 151). Age above 40 years (OR 2.16), working in a government healthcare facility (OR 3.12), participating in COVID-19 vaccine related activities (OR 4.62), and having tested for SARS-COV-2 (OR 3.05) increased the odds of having been vaccinated. Working in small roadside clinics reduced the odds of being vaccinated by almost 70%, while HCWs in government health services were 3.1 times more likely to have been vaccinated. History of having cared for a COVID-19 patient and having a positive SARS-COV-2 test result did not influence the uptake of the vaccines in the study population.

CONCLUSION

Vaccine uptake among HCWs was close to the World Health Organisation (WHO) recommended uptake of 70% by mid-2022.

Vaccine adjuvants: Tailoring innate recognition to send the right message

Adjuvants play pivotal roles in vaccine development, enhancing immunization efficacy through prolonged retention and sustained release of antigen, lymph node targeting, and regulation of dendritic cell activation. Adjuvant-induced activation of innate immunity is achieved via diverse mechanisms: for example, adjuvants can serve as direct ligands for pathogen recognition receptors or as inducers of cell stress and death, leading to the release of immunostimulatory-damage-associated molecular patterns. Adjuvant systems increasingly stimulate multiple innate pathways to induce greater potency. Increased understanding of the principles dictating adjuvant-induced innate immunity will subsequently lead to programming specific types of adaptive immune responses. This tailored optimization is fundamental to next-generation vaccines capable of inducing robust and sustained adaptive immune memory across different cohorts.

Influenza vaccination before and during the COVID-19 pandemic in the elderly in South Korea

BACKGROUND

Influenza epidemics are a significant cause of mortality and morbidity in older adults; thus, vaccination is recommended. However, the coronavirus disease 2019 (COVID-19) pandemic could affect influenza vaccination.

METHODS

The influenza vaccination rate was estimated from the Korea Community Health Survey data from 2011 to 2021 using Joinpoint regression. We used multiple logistic regression analysis from each two flu seasons data before (2017-18 and 2018-19 seasons) and during (2019-20 and 2020-21 seasons) the COVID-19 pandemic to identify older adults who were not been vaccinated during the COVID-19 pandemic. Additionally, we stratified changes in influenza vaccination according to the flu season, demographic and socioeconomic characteristics, and health status.

RESULTS

The annual percentage change in influenza non-vaccination rate from 2010-11 to 2018-19 seasons and from 2019-20 to 2020-21 seasons was -8.31% (confidence interval (CI), -9.60 to -7.00) and 11.41% (CI, -3.22 to 28.25), respectively. Compared to before COVID-19, in the 2019-20 and 2020-21 seasons, the odds ratio (OR) of non-vaccination was 0.87 (CI, 0.83-0.91) and 1.18 (95% CI, 1.13-1.24), respectively. The decrease in influenza vaccination among older individuals with higher education (OR, 1.24; CI, 1.11-1.39) was greater than that among those with lower education (OR, 1.09; CI, 0.98-1.22). Older individuals with the lowest income level or poor self-rated health showed reduced influenza vaccination.

CONCLUSIONS

We estimated the trends of influenza vaccination and identified subgroups with decreased vaccination rates during the COVID-19 pandemic among older adults in South Korea. Health policy decision-makers, practitioners, and researchers should consider the implications of COVID-19 on changes in influenza vaccination, particularly for older individuals at risk of influenza.

Intramuscular vs. Subcutaneous: Rethinking Influenza Vaccination Strategy in Japan

In Japan, inactivated vaccines, including the influenza vaccine, are administered subcutaneously, which is contrary to global recommendations for intramuscular injections. This practice is attributed to historical medical incidents and unchallenged conventions. However, this outdated method, which differs from that of international standards and is linked with less immunogenicity and more adverse reactions, may contribute to vaccination hesitancy. Therefore, with the adoption of intramuscular vaccination administration, which was widely adopted in the coronavirus disease 2019 vaccination, a shift in the Japanese health policy to conform to international standards potentially improves vaccine acceptance and effectiveness.

Influvac Tetra: clinical experience on safety, efficacy, and immunogenicity

INTRODUCTION

This paper summarizes the safety and immunogenicity data of Influvac Tetra across all age groups starting from 6 months of age, obtained during its clinical development program.

AREAS COVERED

The article covers the clinical development program of Influvac Tetra based on five registration studies that included different age groups, different comparators, and participants from Europe and Asia. Safety and immunogenicity were assessed in all studies and in one study, the efficacy of Influvac Tetra was assessed.

EXPERT OPINION

Seasonal influenza is a vaccine-preventable disease that can cause serious complications. Several types of influenza vaccines are available, including egg-based (standard dose, high dose, and adjuvanted), cell-based, and recombinant. The COVID-19 pandemic has stimulated innovation in the development such as mRNA vaccines. However, these vaccines are still in development and the true value still has to be proven. Regardless of the type of vaccine, it is also important to increase overall vaccination coverage. ECDC recommends that EU Member States implement action plans and policies aimed at reaching 75% coverage in at-risk groups and healthcare workers. Even so, vaccine coverage is still far from recommended.

Vaccinating the German Population Aged 60 Years and Over with a Quadrivalent High-Dose Inactivated Influenza Vaccine Compared to Standard-Dose Vaccines: A Transmission and Budget Impact Model

BACKGROUND AND OBJECTIVE

In Germany, influenza vaccination is mainly advised for persons aged 60 years and over and individuals with health risks. Since 2021, an inactivated, quadrivalent high-dose influenza vaccine (IIV4-HD) has been recommended for persons aged 60 years and over. The aim of this study was to calculate the impact of vaccinating the German population aged 60 years and over with IIV4-HD compared to standard-dose influenza vaccines (IIV4-SD) with regard to health outcomes and costs.

METHODS

An age-stratified deterministic compartment model was built to simulate the course of influenza infection for the German population in the season 2019/20. Probabilities for health outcomes and cost data were searched from the literature and were used to compare the influenza-related health and economic effects for different scenarios. Perspectives were those of the statutory health insurance and the society. Deterministic sensitivity analyses were conducted.

RESULTS

From the statutory health insurance perspective, vaccinating the German population aged 60 years and over with IIV4-HD would have prevented 277,026 infections (- 1.1%) with an increase of overall direct costs of €224 million (+ 40.1%) compared with IIV4-SD. A separate analysis showed that increased vaccination of 75% (World Health Organization recommendation for older age groups) in persons aged 60 years and over using IIV4-SD only would prevent 1,289,648 infections (- 5.1%) and would save costs from a statutory health insurance perspective of €103 million (- 13.2%) compared with IIV4-HD at actual vaccination rates.

CONCLUSIONS

The modeling approach offers important insights into the epidemiological and budgetary impact of different vaccination scenarios. Achieving a higher vaccination coverage with IIV4-SD in persons aged 60 years and over would result in lower costs and fewer influenza infections compared with the scenario with IIV4-HD and actual vaccination rates.

Lessons learned from the COVID-19 pandemic for improved influenza control

The World Health Organization noted that COVID-19 vaccination programmes could be leveraged to deliver influenza vaccination. In 2008, the International Federation of Pharmaceutical Manufacturers and Associations' (IFPMA) Influenza Vaccine Supply International Task Force (IVS) developed a survey method using the number of influenza vaccine doses distributed globally to estimate vaccination coverage rates. Seven hundred and ninety-seven million doses were distributed in 2021, representing a 205% increase over the 262 million doses distributed in 2004, exceeding the number of doses distributed during and after the 2009-2010 influenza pandemic. The most obvious explanation for the global increase is the enabling of critical elements of the vaccine ecosystem by decision-makers during the COVID-19 pandemic to reinforce implementation of influenza vaccination programs. Most of the improvements in performance of influenza programs during the COVID-19 pandemic can be classified in four categories: 1) promoting vaccination using tailored approaches for specific populations; 2) improving convenient access to influenza vaccines in COVID-safe settings; 3) improving reimbursement of seasonal influenza vaccination for priority groups; 4) maintaining the timing of vaccination to the autumn. In spite of the increase in rates of seasonal influenza vaccines distributed during the COVID-19 pandemic, globally, the rate of influenza dose distribution is sub-optimal, and a considerable proportion of the influenza infections remains preventable. To sustain the benefits from increased uptake of influenza vaccines, governments need to sustain the efforts made during the COVID-19 pandemic, and a number of global policy endeavours should be undertaken, including developing a clear global roadmap for achieving influenza control objectives, adopted by a WHA resolution, in line with the strategic objective 3 of the Global Influenza Strategy 2030, embedded in the Immunization Agenda 2030 (IA2030).

The Effect of Combining the COVID-19 Vaccine with the Seasonal Influenza Vaccine on Reducing COVID-19 Vaccine Rejection Among Libyans

BACKGROUND

Coronavirus disease 2019 (COVID-19) vaccine coverage remains low in Libya compared to other countries in the Eastern Mediterranean Region. This study aimed to evaluate the willingness of the general public in Libya to receive COVID-19 and seasonal influenza vaccines. Additionally, the study aimed to investigate the potential effect of combining the two vaccines to reduce COVID-19 vaccine rejection.

METHODS

An anonymous nationwide online cross-sectional survey was carried out from 1st September to 16th October 2022. Libyans aged 18 years or older were recruited using convenience and snowball sampling approaches. The participants were surveyed for sociodemographic information, health status, and vaccination attitude towards COVID-19 and seasonal influenza vaccines.

RESULTS

A total of 2484 participants formed the final study sample: 68.7% were females, 39.4% were aged 18-25 years, 50.4% were single, 32.5% had previous COVID-19 infection, and 47.2% experienced COVID-19 death among relatives. Three-fourths of the respondents showed COVID-19 vaccine rejection: 57.3% did not receive COVID-19 vaccination, 10.1% would not complete the primary vaccination series, and 7.8% refused booster doses. About 55.0% rejected seasonal influenza vaccination, while 1.9% reported influenza vaccine uptake and 21.2% were willing to get the influenza vaccine for the first time. Additionally, 18.8% had already received influenza vaccination in the last year and intended to get the vaccine this season, while 3.3% were unwilling to get influenza vaccination this year despite receiving it in the last influenza season. Age, sex, and occupation were significantly associated with COVID-19 and influenza vaccine rejection. Rejection of COVID-19 vaccination decreased if its combination with influenza vaccine as a single dose was suggested, with 28.2% of the COVID-19 vaccine rejector group accepting the combined vaccine as it would be safer (50.9%), needing fewer injections (24.0%), would be more effective (19.1%), and would be less expensive (3%). Approximately 73.0% of the COVID-19 vaccine rejector group refused this combination due to fear of side effects (48.7%), absence of published studies on this combination (29.8%), and considering this combination as useless (11.2%).

CONCLUSION

In Libya, the prevalence of COVID-19 vaccine rejection was high, while the rejection of seasonal influenza vaccination was relatively lower. If influenza and COVID-19 vaccines are administered simultaneously as a single injection, this may reduce the rejection of the COVID-19 vaccine due to better-perceived vaccine safety and efficacy besides being more convenient in terms of the number of injections and cost.

Group 1 and group 2 hemagglutinin stalk antibody response according to age

Objective

Antibodies elicited by seasonal influenza vaccines mainly target the head of hemagglutinin (HA). However, antibodies against the stalk domain are cross-reactive and have been proven to play a role in reducing influenza disease severity. We investigated the induction of HA stalk-specific antibodies after seasonal influenza vaccination, considering the age of the cohorts.

Methods

A total of 166 individuals were recruited during the 2018 influenza vaccine campaign (IVC) and divided into groups: <50 (n = 14), 50-64 (n = 34), 65-79 (n = 61), and ≥80 (n = 57) years old. Stalk-specific antibodies were quantified by ELISA at day 0 and day 28 using recombinant viruses (cH6/1 and cH14/3) containing an HA head domain (H6 or H14) from wild bird origin with a stalk domain from human H1 or H3, respectively. The geometric mean titer (GMT) and the fold rise (GMFR) were calculated, and differences were assessed using ANOVA adjusted by the false discovery rate (FDR) and the Wilcoxon tests (p <0.05).

Results

All age groups elicited some level of increase in anti-stalk antibodies after receiving the influenza vaccine, except for the ≥80-year-old cohort. Additionally, <65-year-old vaccinees had higher group 1 antibody titers versus group 2 before and after vaccination. Similarly, vaccinees within the <50-year-old group showed a higher increase in anti-stalk antibody titers when compared to older individuals (≥80 years old), especially for group 1 anti-stalk antibodies.

Conclusion

Seasonal influenza vaccines can the induction of cross-reactive anti-stalk antibodies against group 1 and group 2 HAs. However, low responses were observed in older groups, highlighting the impact of immunosenescence in adequate humoral immune responses.

Cost-Effectiveness of Vaccination of Older Adults with an MF59®-Adjuvanted Quadrivalent Influenza Vaccine Compared to Standard-Dose and High-Dose Vaccines in Denmark, Norway, and Sweden

Individuals aged 65 years and above are at increased risk of complications and death from influenza compared with any other age group. Enhanced vaccines, as the MF59®-adjuvanted quadrivalent influenza vaccine (aQIV) and the high-dose quadrivalent influenza vaccine (HD-QIV), provide increased protection for older adults in comparison to the traditional standard-dose quadrivalent influenza vaccines (SD-QIV). This study aimed to assess the cost-effectiveness of aQIV compared to SD-QIV and HD-QIV in Denmark, Norway, and Sweden for adults aged ≥65 years. A static decision tree model was used to evaluate costs and outcomes of different vaccination strategies from healthcare payer and societal perspectives. This model projects that compared to SD-QIV, vaccination with aQIV could prevent a combined total of 18,772 symptomatic influenza infections, 925 hospitalizations, and 161 deaths in one influenza season across the three countries. From a healthcare payer perspective, the incremental costs per quality adjusted life year (QALY) gained with aQIV versus SD-QIV were EUR 10,170/QALY in Denmark, EUR 12,515/QALY in Norway, and EUR 9894/QALY in Sweden. The aQIV was cost saving compared with HD-QIV. This study found that introducing aQIV to the entire population aged ≥65 years may contribute to reducing the disease and economic burden associated with influenza in these countries.

AF03 adjuvant improves anti-hemagglutinin and anti-neuraminidase immune responses induced by licensed seasonal quadrivalent influenza vaccines in mice

Seasonal influenza remains a serious public health concern as the viral infection spreads easily from person to person and due to antigenic drift of neutralizing epitopes. Vaccination is the best method for disease prevention, however current seasonal influenza vaccines stimulate antibodies which are often effective against only antigenically similar strains. To boost the immune responses and increase vaccine effectiveness, adjuvants have been used for the past 20 years. The current study explores the use of oil-in-water adjuvant, AF03 to improve an immunogenicity of 2 licensed vaccines. A standard-dose inactivated quadrivalent influenza vaccine (IIV4-SD), containing both hemagglutinin (HA) and neuraminidase (NA) antigens, and recombinant quadrivalent influenza vaccine (RIV4), containing only HA-antigen were adjuvanted with AF03 in naïve BALB/c mouse model. Functional HA-specific antibody titers against all four homologous vaccine strains were enhanced by AF03, indicating potential increase in protective immunity. An increase in HA-specific total immunoglobulin G (IgG) binding titers were detected against homologous HAs, heterologous panel of 30 H3 HAs and seven Influenza B HAs. The neuraminidase inhibition (NAI) activity was significantly higher in IIV4-SD-AF03 group. Use of AF03 adjuvant improved the immune response to two influenza vaccines in a mouse model via an increase in functional and total antibodies against NA and a broad panel of HA-antigens.

Unveiling New Druggable Pockets in Influenza Non-Structural Protein 1: NS1-Host Interactions as Antiviral Targets for Flu

Influenza viruses are responsible for significant morbidity and mortality worldwide in winter seasonal outbreaks and in flu pandemics. Influenza viruses have a high rate of evolution, requiring annual vaccine updates and severely diminishing the effectiveness of the available antivirals. Identifying novel viral targets and developing new effective antivirals is an urgent need. One of the most promising new targets for influenza antiviral therapy is non-structural protein 1 (NS1), a highly conserved protein exclusively expressed in virus-infected cells that mediates essential functions in virus replication and pathogenesis. Interaction of NS1 with the host proteins PI3K and TRIM25 is paramount for NS1's role in infection and pathogenesis by promoting viral replication through the inhibition of apoptosis and suppressing interferon production, respectively. We, therefore, conducted an analysis of the druggability of this viral protein by performing molecular dynamics simulations on full-length NS1 coupled with ligand pocket detection. We identified several druggable pockets that are partially conserved throughout most of the simulation time. Moreover, we found out that some of these druggable pockets co-localize with the most stable binding regions of the protein-protein interaction (PPI) sites of NS1 with PI3K and TRIM25, which suggests that these NS1 druggable pockets are promising new targets for antiviral development.

Prevalence and Predictors of Seasonal Influenza Vaccine Uptake in Saudi Arabia Post COVID-19: A Web-Based Online Cross-Sectional Study

In the fall of 2022, the number of influenza-like illnesses (ILIs) and severe acute respiratory infections (SARIs) in Saudi Arabia had significantly increased compared with the corresponding period in previous years. Concerns regarding the population's seasonal influenza vaccine (SIV) uptake rates have emerged. In particular, the SIV uptake rates may have dropped post the COVID-19 pandemic compared with rates prior to the COVID-19 era. In this study, we aimed to estimate the prevalence and predictors of SIV uptake in Saudi Arabia post the COVID-19 pandemic. We conducted a cross-sectional study utilizing an online survey platform. We mainly collected sociodemographic information and determined whether the respondent was a healthcare professional or had a chronic disease. The overall SIV uptake prevalence was 31.8%. A lower SIV uptake was observed among those aged 55 years or older, females, residents of the central region, non-health practitioners, and those without chronic diseases. Several factors were associated with SIV uptake. Those aged 35-44 were over three-fold more likely to receive an SIV than those aged 55 years or older (OR: 3.66; 95% CI: 1.33-10.05). In addition, males had 73% higher odds of SIV uptake than females (OR: 1.73; 95% CI: 1.18-2.55). Health practitioners were more likely to receive an SIV than non-health practitioners (OR: 2.11; 95% CI: 1.45-3.06). Similarly, those with chronic diseases had 86% higher odds of SIV uptake than those without chronic diseases (OR: 1.86; 95% CI: 1.18-2.95). These findings can provide insights into the low prevalence and predictors of SIV uptake in Saudi Arabia. Future studies should be conducted to further explore the potential factors associated with such a low prevalence of SIV uptake post COVID-19 in Saudi Arabia.

Clinical outcomes and economic burden of seasonal influenza and other respiratory virus infections in hospitalized adults

The cost of influenza and other respiratory virus infections should be determined to analyze the real burden of these diseases. We aimed to investigate the clinical outcomes and cost of illness due to respiratory virus infections in hospitalized adult patients. Hospitalized patients who had nasal swab sampling for a suspected viral infection between August 1, 2018 to March 31, 2019 were included. Outcome variables were oxygen requirement, mechanical ventilation need, intensive care unit admission, and cost. At least one viral pathogen was detected in 125 (47.7%) of 262 patients who were included in the study. Fifty-five (20.9%) of the patients were infected with influenza. Influenza-positive patients had higher rates for respiratory support, intensive care unit admission, and mortality compared to all other patients. The average cost of hospitalization per person was 2879.76 USD in the influenza-negative group, while the same cost was 3274.03 USD in the influenza-positive group. Although all of the vaccinated influenza-positive patients needed oxygen support, neither of them required invasive mechanical ventilation or intensive care unit admission. The average hospitalization cost per person was 779.70 USD in the vaccinated group compared to 3762.01 USD in the unvaccinated group. Disease-related direct cost of influenza in the community was estimated as 22 776 075.61 USD in the 18-65 years of age group and 15 756 120.02 USD in the 65 years of age and over group per year. Influenza, compared to other respiratory virus infections, can lead to untoward clinical outcomes and mortality as well as higher direct medical costs in adults.

Clinical and economic burden of physician-diagnosed influenza in adults during the 2017/2018 epidemic season in Spain

BACKGROUND

Influenza is an acutely debilitating respiratory infection, contributing significantly to outpatient visits and hospitalizations. Spain lacks comprehensive and updated data on the burden of influenza, particularly in the outpatient setting. Our study aimed to fill this gap by estimating the clinical and economic burden of physician-diagnosed influenza cases in adults from four Spanish regions, stratified by age groups and presence of comorbidities.

METHODS

A retrospective cost-of-illness study was conducted using data from an electronic medical records database from the National Healthcare Service (NHS) of four Spanish regions for individuals aged ≥ 18 years diagnosed for influenza during the 2017/2018 epidemic season. Health resource utilization and related cost data were collected, including primary care visits, referrals to other specialists, visits to the emergency department, hospitalizations, and prescribed medicines.

RESULTS

The study reported a total of 28,381 patients aged ≥ 18 years diagnosed with influenza, corresponding to 1,804 cases per 100,000 population. Most patients were aged < 65 years: 60.5% (n = 17,166) aged 18-49 and 26.3% (n = 7,451) 50-64 years. A total of 39.2% (n = 11,132) of patients presented a comorbidity. Cardiovascular diseases were the most common comorbidity reported along with influenza. The mean healthcare cost per case was estimated at €235.1 in population aged 18-49 years, increasing by 1.7 and 4.9 times in those aged 50-64 (€402.0) and ≥ 65 (€1,149.0), respectively. The mean healthcare cost per case was 3.2 times higher in patients with comorbidities. The total healthcare cost of medically attended influenza cases was mainly driven by primary care (45.1%) and hospitalization (42.0%). Patients aged 18-64 years old accounted for 61.9% of the costs of medically attended influenza. Irrespective of age, patients with comorbidities accounted for 67.1% of costs.

CONCLUSIONS

Season 2017/2018 was associated with a considerable burden of influenza in Spain, which increased with age and presence of comorbidities. Individuals with comorbidities accounted for most of the costs of influenza. Results suggest that population aged 18-64 years old is generating the highest share of costs to the NHS when all healthcare costs are considered. Preventive strategies targeting subjects with comorbidities, regardless of age, should be warranted.

A Malaysian consensus recommendation for the prevention of influenza in older persons

BACKGROUND

Older persons are at high-risk of developing severe complications from influenza. This consensus statement was developed to provide guidance on appropriate influenza prevention strategies relevant to the Malaysian healthcare setting.

METHODS

Under the initiative of the Malaysian Influenza Working Group (MIWG), a panel comprising 11 multi-speciality physicians was convened to develop a consensus statement. Using a modified Delphi process, the panellists reviewed published evidence on various influenza management interventions and synthesised 10 recommendations for the prevention of influenza among the aged population via group discussions and a blinded rating exercise.

RESULTS

Overall, annual influenza vaccination is recommended for individuals aged ≥ 60 years, particularly those with specific medical conditions or residing in aged care facilities (ACFs). There is no preference for a particular vaccine type in this target population. Antiviral agents can be given for post-exposure chemoprophylaxis or when vaccine contraindication exists. Infection control measures should serve as adjuncts to prevent the spread of influenza, especially during Hajj.

CONCLUSION

This consensus statement presents 10 evidence-based recommendations that can be adopted by healthcare providers to prevent influenza among the aged population in Malaysia. It could also serve as a basis for health policy planning in other lower- and middle-income countries.

Immunodominance hierarchy after seasonal influenza vaccination

Current influenza vaccines elicit humoral immune responses against the hemagglutinin (HA) protein of influenza viruses. Different antigenic sites have been identified in the HA head as the main target of hemagglutination inhibition (HAI) antibodies (Sb, Sa, Cb, Ca1 and Ca2). To determine immunodominance (ID) of each site, we performed HAI assays against a panel of mutant viruses, each one lacking one of the classically defined antigenic sites and compared it to wild type (Wt). Agglutinating antibodies were measured before and after vaccination in two different regimens: Quadrivalent Influenza Vaccine (QIV) in young adults; or Adjuvanted Trivalent influenza Vaccine (ATIV) in elderly. Our results showed abs before vaccination were significantly reduced against all antigenic sites in the elderly and only against Sb and Ca2 in young adults compared to the Wt. Humoral response to vaccination was significantly reduced against all viruses compared to the Wt for the ATIV and only against Sb and Ca2 for the QIV. The strongest reduction was observed in all cases against Sb followed by Ca2. We concluded that ID profile was clearly dominated by Sb followed by Ca2. Additionally, the antibody response evolved with age, increasing the response towards less immunodominant epitopes of HA head. Adjuvants can positively influence ID hierarchy broadening responses towards multiple antigenic sites of HA head.

Influenza Vaccination Assessment according to a Value-Based Health Care Approach

Background: Seasonal influenza has a considerable public health impact, and vaccination is the key to preventing its consequences. Our aim was to describe how the value of influenza vaccination is addressed in the scientific literature considering a new value framework based on four pillars (personal, allocative, technical, and societal value). Methods: A systematic review was conducted by querying three databases. The analysis was performed on international studies focused on influenza vaccination value, and the four value pillars were taken into consideration for their description. Results: Overall, 40 studies were considered. Most of them focused on influenza vaccination in the general population (27.5%), emphasizing its value for all age groups. Most studies addressed technical value (70.4%), especially in terms of economic models and cost drivers to be considered for the economic evaluations of influenza vaccines, and societal value (63%), whereas few dealt with personal (37%) and allocative values (22.2%). Conclusions: The whole value of influenza vaccination is still not completely recognized. Knowledge and communication of the whole value of influenza vaccination is essential to guide value-based health policies. To achieve this goal, it is necessary to implement initiatives that involve all relevant stakeholders.

Quadrivalent Vaccines for the Immunization of Adults against Influenza: A Systematic Review of Randomized Controlled Trials

Vaccination is the most effective intervention to prevent influenza. Adults at risk of complications are among the targets of the vaccination campaigns and can be vaccinated with different types of quadrivalent influenza vaccines (QIVs). In the light of assessing the relative immunogenicity and efficacy of different QIVs, a systematic review was performed. Randomized controlled trials conducted in adults aged 18–64 years until 30 March 2021 were searched through three databases (Medline, Cochrane Library and Scopus). Twenty-four RCTs were eventually included. After data extraction, a network meta-analysis was not applicable due to the lack of common comparators. However, in the presence of at least two studies, single meta-analyses were performed to evaluate immunogenicity and efficacy; on the contrary, data from single studies were considered. Seroconversion rate for H1N1 was higher for standard QIVs, while for the remaining strains it was higher for low-dose adjuvanted QIVs. For seroprotection rate, the recombinant vaccine recorded the highest values for H3N2, while for the other strains, the cell-based QIVs achieved better results. In general, standard and cell-based QIVs showed an overall good immunogenicity profile. Nevertheless, as a relative comparative analysis was not possible, further research would be deserved.

Assembly of Poly(ethylene glycol)ylated Oleanolic Acid on a Linear Polymer as a Pseudomucin for Influenza Virus Inhibition and Adsorption

Biomimicry of the mucin barrier function is an efficient strategy to counteract influenza. We report the simple aminolyzation of poly(methyl vinyl ether-alt-maleic anhydride) (PM) using amine-terminated poly(ethylene glycol)ylated oleanolic acid (OAPEG) to mimic the mucin structure and its adsorption of the influenza virus. Direct interactions between influenza hemagglutinin (HA) and the prepared macromolecule evaluated by surface plasmon resonance and isothermal titration calorimetry demonstrated that the multivalent presentation of OAPEG on PM enhanced the binding affinity to HA with a decrease in K_D of approximately three orders of magnitude compared with monomeric OAPEG. Moreover, hemagglutination inhibition assay, viral growth inhibition assay, and cytopathic effect reduction assay indicated that the nonglycosylated polymer could mimic natural heavily glycosylated mucin and thus promote the attachment of the virus in a subnanomolar range. Further investigation of the antiviral effects via time-of-addition assay, dynamic light scattering experiments, and transmission electron microscopy photographs indicated that the pseudomucin could adsorb the virion particles and synergistically inhibit the early attachment and final release steps of the influenza infection cycle. These findings demonstrate the effectiveness of the macromolecule in the physical sequestration and prevention of viral infection. Notably, due to its structural similarities with mucin, the biomacropolymer also has the potential for the rational design of antiviral drugs, influenza adsorbents, or filtration materials and the construction of model systems to explore protection against other pathogenic viruses.

The economic burden of influenza among adults aged 18 to 64: A systematic literature review

While the economic burden of influenza infection is well described among adults aged 65 and older, less is known about younger adults. A systematic literature review was conducted to describe the economic burden of seasonal influenza in adults aged 18 to 64 years, to identify the main determinants of direct and indirect costs, and to highlight any gaps in the existing published evidence. MEDLINE and Embase were searched from 2007 to February 7, 2020, for studies reporting primary influenza-related cost data (direct or indirect) or absenteeism data. Of the 2613 publications screened, 51 studies were included in this review. Half of them were conducted in the United States, and 71% of them described patients with influenza-like illness rather than laboratory-confirmed disease. Only 12 studies reported cost data specifically for at-risk populations. Extracted data highlighted that within the 18- to 64-year-old group, up to 88% of the economic burden of influenza was attributable to indirect costs, and up to 75% of overall direct costs were attributable to hospitalizations. Furthermore, within the 18- to 64-year-old group, influenza-related costs increased with age and underlying medical conditions. The reported cost of influenza-related hospitalizations was found to be up to 2.5 times higher among at-risk populations compared with not-at-risk populations. This review documents the considerable economic impact of influenza among adults aged 18 to 64. In this age group, most of the influenza costs are indirect, which are generally not recognized by decision makers. Future studies should focus on at-risk subgroups, lab-confirmed cases, and European countries.

The Value(s) of Vaccination: Building the Scientific Evidence According to a Value-Based Healthcare Approach

Objectives

To provide a new value-based immunization approach collating the available scientific evidence on the topic.

Methods

Four value pillars (personal, allocative, technical, and societal) applied to vaccination field were investigated. A systematic literature review was performed querying three database from December 24th, 2010 to May 27th, 2020. It included studies on vaccine-preventable diseases (VPDs) that mentioned the term value in any part and which were conducted in advanced economies. An in-depth analysis was performed on studies addressing value as key element.

Results

Overall, 107 studies were considered. Approximately half of the studies addressed value as a key element but in most of cases (83.3%) only a single pillar was assessed. Furthermore, the majority of papers addressed the technical value by looking only at classical methods for economic assessment of vaccinations whereas very few dealt with societal and allocative pillars.

Conclusions

Estimating the vaccinations value is very complex, even though their usefulness is certain. The assessment of the whole value of vaccines and vaccinations is still limited to some domains and should encompass the wider impact on economic growth and societies.

Workplace influenza vaccination in private hospital setting: a cost-benefit analysis

Background

Influenza illness causes several disruptions to the workforce. The absenteeism that often ensues has economic implications for employers. This study aimed to estimate the cost-benefit of influenza vaccination in a healthcare setting from the employer’s perspective.

Methods

A cross-sectional questionnaire survey was conducted in a private hospital in 2018–2019 comparing voluntary vaccinated with non-vaccinated employees with influenza vaccine. The analyses were made based on self-reporting on absenteeism and presenteeism from Influenza-like illnesses (ILIs). The costs incurred, both direct and indirect costs, were included in the study. A cost-benefit analysis was performed by measuring the cost of the vaccination program. The costs of absenteeism and reduced productivity were calculated using 3 hypothesised levels of effectiveness in the following percentage of productivity of 30%, 50%, and 70%. The costs were also calculated based on four scenarios: with and without operating income and with and without replacement. The benefits of the influenza vaccination from the employer’s perspective were analysed. The benefit to cost ratio was determined.

Results

A total of four hundred and twenty-one respondents participated. The influenza vaccination rate was 63.0%. The rate of ILI of 38.1% was significantly lower among vaccinated. The ILI-related absenteeism reported was also significantly lower amongst vaccinated employees at 30% compared to 70% non-vaccinated. Employers could save up to USD 18.95 per vaccinated employee when only labour cost was included or 54.0% of cost savings. The cost-saving rose to USD 155.56 when the operating income per employee was also included. The benefit to cost ratio confirmed that the net cost-benefit gained from the vaccination was more than the net cost of vaccination.

Conclusions

Influenza vaccination for working adults was cost-saving and cost-beneficial when translated into financial investments for the employer. A workplace vaccination demonstrates a significant cost-benefit strategy to be applied in any institutional setting.

Estimation of Reduction in Influenza Vaccine Effectiveness Due to Egg-Adaptation Changes-Systematic Literature Review and Expert Consensus

BACKGROUND

Influenza vaccines are the main tool to prevent morbidity and mortality of the disease; however, egg adaptations associated with the choice of the manufacturing process may reduce their effectiveness. This study aimed to estimate the impact of egg adaptations and antigenic drift on the effectiveness of trivalent (TIV) and quadrivalent (QIV) influenza vaccines.

METHODS

Nine experts in influenza virology were recruited into a Delphi-style exercise. In the first round, the experts were asked to answer questions on the impact of antigenic drift and egg adaptations on vaccine match (VM) and influenza vaccine effectiveness (IVE). In the second round, the experts were presented with the data from a systematic literature review on the same subject and aggregated experts' responses to round one questions. The experts were asked to review and confirm or amend their responses before the final summary statistics were calculated.

RESULTS

The experts estimated that, across Europe, the egg adaptations reduce, on average, VM to circulating viruses by 7-21% and reduce IVE by 4-16%. According to the experts, antigenic drift results in a similar impact on VM (8-24%) and IVE (5-20%). The highest reduction in IVE was estimated for the influenza virus A(H3N2) subtype for the under 65 age group. When asked about the frequency of the phenomena, the experts indicated that, on average, between the 2014 and 19 seasons, egg adaptation and antigenic drift were significant enough to impact IVE that occurred in two and three out of five seasons, respectively. They also agreed that this pattern is likely to reoccur in future seasons.

CONCLUSIONS

Expert estimates suggest there is a potential for 9% on average (weighted average of "All strains" over three age groups adjusted by population size) and up to a 16% increase in IVE (against A(H3N2), the <65 age group) if egg adaptations that arise when employing the traditional egg-based manufacturing process are avoided.

Safety Profile of GSK's Inactivated Quadrivalent Seasonal Influenza Vaccine in Belgium, Germany and Spain: Passive Enhanced Safety Surveillance Study for the 2019/2020 Influenza Season

Introduction

Seasonal influenza infects millions annually in Europe. Annual influenza vaccination is the most effective measure to reduce the risk of infection and its complications, especially among young children and older adults.

Objective

We assessed adverse event (AE) frequency after receiving GSK’s inactivated quadrivalent seasonal influenza vaccine (IIV4).

Methods

A passive enhanced safety surveillance study was conducted in Belgium, Germany, and Spain. Adults who had received GSK's IIV4 or the parent(s)/guardian(s)/legally acceptable representative(s) of children given the vaccine were invited to complete an adverse drug reaction (ADR) card to document AEs experienced within 7 days post vaccination.

Results

A total of 1082 participants (51.6% females) received GSK's IIV4, including 115 children < 9 years of age who received two doses. The ADR card return rate was 97.0% (n = 1049) after dose 1 and 100% (n = 115) after dose 2. All participants in Belgium and Germany were adults. In Spain, 71.2% were children. After dose 1, 39.2% reported one or more AE. The most frequent AEs category was "general disorders and administration site conditions” (GDASC). AEs were most frequently reported in adults aged 18–65 years (47.2%), followed by children aged 6 months–17 years (38.1%), and adults aged > 65 years (31.6%). After dose 2, 7.8% reported one or more AE, and GDASC was again the most frequent AE category. There were no serious AEs related to GSK's IIV4 within 7 days post vaccination.

Conclusion

No serious AEs related to GSK’s IIV4 within 7 days post vaccination were reported. This study supports the favourable risk–benefit safety profile of GSK’s IIV4.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40264-021-01121-8.

Seasonal influenza infects millions annually in Europe, especially young children and older adults. Annual influenza vaccination is the most effective measure to reduce the risk of infection and its complications. As the wild influenza virus strains change every year, the composition of the influenza vaccine changes as well. Since the vaccine is produced in the same way over the years, extensive safety studies are no longer required by regulatory authorities. Instead, monitoring of any unwanted medical incidents (adverse events) after vaccination is required. For the 2019/2020 season, we monitored the adverse events reported by a representative sample of people in Belgium, Germany, and Spain within 7 days after receiving GSK's seasonal influenza vaccine.

Of the 1082 people who received the first dose of the vaccine, 39% reported at least one adverse event, such as pain and swelling at the injection site, tiredness, fever, headache, or dizziness. A total of 115 children under 9 years of age received two doses 4 weeks apart. After their second dose, few of these children (8%) reported adverse events. The most frequent adverse events were fever, swelling and pain at the injection site, runny nose, or irritability. No serious adverse events were reported after either the first or second dose.

No serious adverse events related to GSK’s seasonal influenza vaccine within the 7 days after vaccination were reported. This study supports the favourable risk–benefit safety profile of GSK's seasonal influenza vaccine.

Vaccine complacency and dose distribution inequities limit the benefits of seasonal influenza vaccination, despite a positive trend in use

Sustainable demand for seasonal influenza vaccines is a component of national security strategies for pandemic preparedness. However, the ongoing COVID-19 pandemic has revealed many weaknesses in the capacity of countries to design and execute sustainable vaccination programs. An influenza pandemic remains a global threat and yet there is no global monitoring system for assessing progress towards influenza vaccination coverage targets. The International Federation of Pharmaceutical Manufacturers and Associations’ (IFPMA) Influenza Vaccine Supply International Task Force (IVS) developed a survey method in 2008 to estimate seasonal influenza vaccination coverage rates, which in turn serves as a crude estimate of pandemic preparedness. It provides evidence to guide expanded efforts for pandemic preparedness, specifically for increasing COVID-19 vaccine immunization levels. Furthermore, the results presented herein serve as a proxy for assessing the state of pandemic preparedness at a global and regional level. This paper adds data from 2018 and 2019 to the previous analyses. The current data show an upward or stable global trend in seasonal influenza vaccine dose distributed per 1,000 population with a 7% increase between 2017 and 2018 and 6% increase between 2018 and 2019. However, considerable regional inequities in access to vaccine persist. Three regions, Africa, the Middle-east, and Southeast Asia together account for 50% of the global population but only 6% of distributed seasonal influenza vaccine doses. This is an important finding in the context of the ongoing COVID-19 pandemic, as distribution of influenza vaccine doses in many ways reflects access to COVID-19 vaccines. Moreover, improving seasonal vaccine uptake rates is critical for optimizing the annual benefits by reducing the huge annual influenza-associated societal burdens and by providing protection to vulnerable individuals against serious complications from seasonal influenza infections.

Safety and Efficacy of Spray Intranasal Live Attenuated Influenza Vaccine: Systematic Review and Meta-Analysis

Although influenza is a major public health concern, little is known about the use of spray live attenuated influenza vaccine (LAIV) among adults. For this reason, we conducted a systematic review and meta-analysis to investigate the efficacy and safety of LAIV, especially in adults with/without clinical conditions and children <2 years, with the final aim of possibly extending the clinical indications. PubMed/MEDLINE and Scopus were the two databases consulted through February 2021. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. A critical appraisal was conducted. Analyses were performed by using ProMeta3 software. Twenty-two studies were included, showing that LAIV was associated with a higher probability of seroconversion when compared with a placebo and considering the A/H1N1 serotype (pooled OR = 2.26 (95% CI = 1.12–4.54), p-value = 0.022; based on 488 participants, without heterogeneity (I2 = 0.0%)). The meta-analysis also confirmed no significant association with systemic adverse events. Only rhinorrhea, nasal congestion, and sore throat were significantly associated with LAIV compared to the placebo. Despite limited available evidence, LAIV has proved to be a safe and effective flu vaccination, also due to its very low invasiveness, and our review’s results can be considered a starting point for guiding future research and shaping forthcoming vaccination campaigns.

Examining Vaccine Hesitancy in Sub-Saharan Africa: A Survey of the Knowledge and Attitudes among Adults to Receive COVID-19 Vaccines in Ghana

The impact of COVID-19 vaccination programmes on disease transmission, morbidity and mortality relies heavily on the population's willingness to accept the vaccine. We explore Ghanaian adult citizens' vaccine hesitancy attitudes and identify the likelihood of participation or non-participation in the government's effort to get citizens vaccinated. A fully anonymised cross-sectional online survey of 2345 adult Ghanaians was conducted from 23 to 28 February 2021. Differences in intentions regarding COVID-19 vaccination were explored using Pearson Chi-square tests. Additionally, multinomial logistic regression was used to analyse the factors associated with willingness to receive vaccines. Responses were weighted using the iterative proportional fitting technique to generate a representative sample. About half (51%) of mostly urban adult Ghanaians over 15 years are likely to take the COVID-19 vaccine if made generally available. Almost a fifth (21%) of the respondents were unlikely to take the vaccine, while another 28% were undecided. Additionally, we find differences in vaccine hesitancy among some socio-demographic characteristics such as age, gender, and primary sources of information. Attaining the proverbial 63% to 70% herd immunity threshold in Ghana is only possible if the preventive vaccination programmes are combined with an enhanced and coordinated public education campaign. Such a campaign should focus on promoting the individual and population-level benefits of vaccination and pre-emptive efforts towards addressing misinformation about vaccines.

Immunization funding across 28 European countries

INTRODUCTION

Disease prevention and improving vaccination coverage in Europe are key elements contributing to resilient health systems and ensuring better health outcomes for all. The aim of this study was to describe the immunization funding landscape across all European Union 28 countries (EU28).

AREAS COVERED

Data collected in a targeted literature review supported descriptive analysis on the different indicators that were looked at: vaccines included in the EU28 national immunization programs (NIP), national immunization funding, immunization funding per capita (2015-2019) and percentage of health-care budget allocated to immunization.

EXPERT OPINION

Immunization funding represents a small proportion of total healthcare spend in Europe (median 0.3%). In the context of the current COVID-19 pandemic, demographic changes, and the potential introduction of new vaccines; the need for adequate financing of immunization programs will be important, to establish resilient immunization systems and provide sustainable protection of the population against vaccine-preventable diseases.

Improved storage of influenza HA-VLPs using a trehalose-glycerol natural deep eutectic solvent system

Vaccines are typically stored under refrigerated conditions (2-8 °C) to limit potency and efficacy loss. Maintaining the cold chain is costly and prone to vaccine wastage due to unexpected changes in the storage conditions. The development of formulations conferring enhanced stability can extend vaccine shelf-life and facilitate storage under non-refrigerated conditions, thus simplifying the distribution process and reducing vaccine wastage. In this study, the suitability of a natural deep eutectic system (NADES) consisting of trehalose and glycerol (TGly) for storage of influenza hemagglutinin (HA)-displaying virus-like particles (VLPs) was successfully demonstrated. TGly was efficient in maintaining the activity and physical integrity of HA-VLPs for up to 4 h at 50 °C (accelerated stability study), with half-life values ≈ 20-34 h for the best TGly formulations. Importantly, improved storage is achieved at increasingly higher TGly concentrations, hence confirming the importance of TGly content in its protective capacity. In addition, HA-VLPs were stable in TGly for over one month at room temperature (short-term stability study), with no impact on HA titer or particle size distribution. This work highlights the potential of NADES to improve stability of VLP-based vaccines, showing promising protective capacity under non-refrigerated conditions and short-term thermal stress, and thus having a notable impact on vaccine's cold chain.

Ancillary benefits of seasonal influenza vaccination in middle-income countries

While seasonal influenza vaccines (SIV) remain the best method to prevent influenza-associated illnesses, implementing SIV programs may benefit countries beyond disease reduction, strengthening health systems and national immunization programs, or conversely, introduce new challenges. Few studies have examined perceived impacts of SIV introduction beyond disease reduction on health systems; understanding such impacts will be particularly salient in the context of COVID-19 vaccine introduction. We collected qualitative data from key informants-Partnership for Influenza Vaccine Introduction (PIVI) contacts in six middle-income PIVI vaccine recipient countries-to understand perceptions of ancillary benefits and challenges from SIV implementation. Respondents reported benefits associated with SIV introduction, including improved attitudes to SIV among risk groups (characterized by increased demand) and perceptions that SIV introduction improved relationships with other ministries and collaboration with mass media. Challenges included sustaining investment in SIV programs, as vaccine supply did not always meet coverage goals, and managing SIV campaigns.

Protective Intranasal Immunization Against Influenza Virus in Infant Mice Is Dependent on IL-6

Respiratory diseases adversely affect infants and are the focus of efforts to develop vaccinations and other modalities to prevent disease. The infant immune system differs from that of older children and adults in many ways that are as yet ill understood. We have used a C57BL/6 mouse model of infection with a laboratory- adapted strain of influenza (PR8) to delineate the importance of the cytokine IL-6 in the innate response to primary infection and in the development of protective immunity in adult mice. Herein, we used this same model in infant (14 days of age) mice to determine the effect of IL-6 deficiency. Infant wild type mice are more susceptible than older mice to infection, similar to the findings in humans. IL-6 is expressed in the lung in the early response to PR8 infection. While intramuscular immunization does not protect against lethal challenge, intranasal administration of heat inactivated virus is protective and correlates with expression of IL-6 in the lung, activation of lung CD8 cells, and development of an influenza-specific antibody response. In IL-6 deficient mice, this response is abrogated, and deficient mice are not protected against lethal challenge. These studies support the importance of the role of the tissue environment in infant immunity, and further suggest that IL-6 may be helpful in the generation of protective immune responses in infants.

The disease burden of influenza beyond respiratory illness

Although influenza is primarily considered a respiratory infection and causes significant respiratory mortality, evidence suggests that influenza has an additional burden due to broader consequences of the illness. Some of these broader consequences include cardiovascular events, exacerbations of chronic underlying conditions, increased susceptibility to secondary bacterial infections, functional decline, and poor pregnancy outcomes, all of which may lead to an increased risk for hospitalization and death. Although it is methodologically difficult to measure these impacts, epidemiological and interventional study designs have evolved over recent decades to better take them into account. Recognizing these broader consequences of influenza virus infection is essential to determine the full burden of influenza among different subpopulations and the value of preventive approaches. In this review, we outline the main influenza complications and societal impacts beyond the classical respiratory symptoms of the disease.

How involvement of community pharmacies improves accessibility to and awareness about flu vaccination? - An example from Estonia

BACKGROUND

In Estonia, seasonal influenza vaccination coverage is poor, being in recent years the lowest in the older age groups. In 2018 the flu vaccination was first provided at community pharmacies in Estonia. The aims of this study were to evaluate the experience of flu vaccination at community pharmacies by pharmacy customers and to learn about the perception of community pharmacists regarding the immunization service.

METHOD

Two cross-sectional surveys: among pharmacy customers after receiving flu vaccination (n = 257), and for pharmacy professionals (n = 209). Descriptive statistics were calculated in both studies.

RESULTS

In the pharmacy customers` study, 54.9% received flu vaccination for the first time. Most of the respondents (96.8%) were satisfied with the quality of service. In both studies, community pharmacies were described as an accessible and convenient setting for immunization. Age and working experience of pharmacy professionals influenced the readiness to provide flu immunization, with younger pharmacists (<36 years) keener to be involved in vaccination services (p < 0.01).

EXPERT OPINION

Increasing influenza vaccination in high-risk patient groups is crucial. The involvement of other healthcare professionals, such as community pharmacists, could be key to reaching these patient groups and improving access to vaccination services in general. The development of the pharmacy profession has also shifted from pharmaceutical product based to patient oriented approach with provision of more clinical services. This enables to use professional competency of pharmacists in healthcare more widely. Lack of resources (financial, healthcare professionals, etc.) and an aging population are driving new ways to deliver healthcare more efficiently with the pharmacist working with other healthcare providers taking greater responsibility for patient health outcomes.

CONCLUSION

Vaccination service at community pharmacy has a great potential to expand flu immunization coverage in Estonia. Despite on pharmacy professionals are not allowed to provide vaccination service at the moment, their contribution to increase public awareness about flu vaccination is significant.

COVID-19: Second Wave or Multiple Peaks, Natural Herd Immunity or Vaccine - We Should be Prepared

Between December 31, 2019, and August 30, 2020 (date of this article), the novel coronavirus and its corresponding infection, coronavirus disease (COVID-19), increased to more than 25 million cases, and 843 158 deaths have been registered. Countries around the world have been affected, albeit in different levels and intensities.Despite implementations of preventive public health measures, most countries are seriously preparing for 1 or more waves. The threat of this surge is likely to persist until herd immunity is acquired either by natural infection or through vaccination. However, given the time frame needed for herd immunity to occur and the low probability that a vaccine will be available on a global scale by the coming fall and winter seasons, contingency preparedness plans should be established and put in place for the coming days or months. These plans should help mitigate new peaks of the pandemic while relaxing the social isolation rules, patient, public health, and hospital levels.In this article, we discuss recommendations that practicing physicians and public health agencies should provide to individuals, especially those at risk of infection, to take and implement pre-emptive measures in anticipation of the potential next peak of the pandemic.

Assessment of the benefits of seasonal influenza vaccination: Elements of a framework to interpret estimates of vaccine effectiveness and support robust decision-making and communication

Systematic reviews and meta‐analyses confirm that influenza vaccination reduces the risk of influenza illness by between about 40% and 60% in seasons when circulating influenza stains are well matched to vaccine strains. Influenza vaccine effectiveness (IVE) estimates, however, are often discordant and a source of confusion for decision makers. IVE assessments are increasingly publicized and are often used by policy makers to make decisions about the value of seasonal influenza vaccination. But there is limited guidance on how IVE should be interpreted or used to inform policy. There are several limitations to the use of IVE for decision‐making: (a) IVE studies have methodological issues that often complicate the interpretation of their value; and (b) the full impact of vaccination will almost always be greater than the impact assessed by a point estimate of IVE in specific populations or settings. Understanding the strengths and weaknesses of study methodologies and the fundamental limitations of IVE estimates is important for the accuracy of interpretations and support of policy makers’ decisions. Here, we review a comprehensive set of issues that need to be considered when interpreting IVE and determining the full benefits of influenza vaccination. We propose that published IVE values should be assessed using an evaluative framework that includes influenza‐specific outcomes, types of VE study design, and confounders, among other factors. Better interpretation of IVE will improve the broader assessment of the value of influenza vaccination and ultimately optimize the public health benefits in seasonal influenza vaccination.

Burden of influenza in Romania. A retrospective analysis of 2014/15 - 2018/19 seasons in Romania

Introduction

Influenza is a seasonal epidemic with a heavy negative impact both on population health, and healthcare system utilization; until now, there are only two burden of disease studies in the Romanian context. This study aims to quantify the burden of influenza for the Romanian population for the seasons 2014/15 to 2018/19, using health administrative databases.

Methods

Incidence, hospitalization and mortality rates attributable to influenza as well as total number of influenza cases and deaths were estimated, for each season in the analyzed period, by combining the new cases reported by General Practitioners, Emergency Department presentations, hospitalizations, number of deaths, positivity rate of influenza, and probability to be consulted by a physician. Years of life lost due to premature death attributable to influenza complications were also computed.

Results

On average, 591,151 cases/season attributable to influenza were estimated during the period 2014/15 - 2018/19. The highest rates for incidence, hospitalization and presentation to emergency department were found in the age groups 0-4 years and 65 years and above. Influenza mortality rate was estimated at 3 per 100,000 persons and the 65 and above age group had the highest rate.

Conclusions

About 3% of the total Romanian population is estimated to develop an influenza attributable disease in a non-pandemic season. An overall increasing trend of the mortality rate attributable to influenza may be also underlined. On average, a person loses 12 years due to premature death caused by complications of influenza.

Communicating Benefits from Vaccines Beyond Preventing Infectious Diseases

Despite immunisation being one of the greatest medical success stories of the twentieth century, there is a growing lack of confidence in some vaccines. Improving communication about the direct benefits of vaccination as well as its benefits beyond preventing infectious diseases may help regain this lost confidence. A conference was organised at the Fondation Merieux in France to discuss what benefits could be communicated and how innovative digital initiatives can used for communication. During this meeting, a wide range of indirect benefits of vaccination were discussed. For example, influenza vaccination can reduce hospitalisations and deaths in older persons with diabetes by 45% and 38%, respectively, but the link between influenza and complications from underlying chronic non-communicable diseases such as diabetes is frequently underestimated. Vaccination can reduce antimicrobial resistance (AMR), which is growing, by reducing the incidence of infectious disease (though direct and indirect or herd protection), by reducing the number of circulating AMR strains, and by reducing the need for antimicrobial use. Disease morbidity and treatment costs in the elderly population are likely to rise substantially, with the ageing global population. Healthy ageing and life-course vaccination approaches can reduce the burden of vaccine-preventable diseases, such as seasonal influenza and pneumococcal diseases, which place a significant burden on individuals and society, while improving quality of life. Novel disease surveillance systems based on information from Internet search engines, mobile phone apps, social media, cloud-based electronic health records, and crowd-sourced systems, contribute to improved awareness of disease burden. Examples of the role of new techniques and tools to process data generated by multiple sources, such as artificial intelligence, to support vaccination programmes, such as influenza and dengue, were discussed. The conference participants agreed that continual efforts are needed from all stakeholders to ensure effective, transparent communication of the full benefits and risks of vaccination.

Impact of influenza vaccination programmes among the elderly population on primary care, Portugal, Spain and the Netherlands: 2015/16 to 2017/18 influenza seasons

Background

To increase the acceptability of influenza vaccine, it is important to quantify the overall benefits of the vaccination programme.

Aim

To assess the impact of influenza vaccination in Portugal, Spain and the Netherlands, we estimated the number of medically attended influenza-confirmed cases (MAICC) in primary care averted in the seasons 2015/16 to 2017/18 among those ≥ 65 years.

Methods

We used an ecological approach to estimate vaccination impact. We compared the number of observed MAICC (n) to the estimated number that would have occurred without the vaccination programme (N). To estimate N, we used: (i) MAICC estimated from influenza surveillance systems, (ii) vaccine coverage, (iii) pooled (sub)type-specific influenza vaccine effectiveness estimates for seasons 2015/16 to 2017/18, weighted by the proportion of virus circulation in each season and country. We estimated the number of MAICC averted (NAE) and the prevented fraction (PF) by the vaccination programme.

Results

The annual average of NAE in the population ≥ 65 years was 33, 58 and 204 MAICC per 100,000 in Portugal, Spain and the Netherlands, respectively. On average, influenza vaccination prevented 10.7%, 10.9% and 14.2% of potential influenza MAICC each season in these countries. The lowest PF was in 2016/17 (4.9–6.1%) with an NAE ranging from 24 to 69 per 100,000.

Conclusions

Our results suggest that influenza vaccination programmes reduced a substantial number of MAICC. Together with studies on hospitalisations and deaths averted by influenza vaccination programmes, this will contribute to the evaluation of the impact of vaccination strategies and strengthen public health communication.

Spread of vaccine hesitancy in France: What about YouTube™?

OBJECTIVES

This work characterises the information about vaccination available on YouTube™ in France.

METHODS

YouTube™ (www.YouTube.com) was searched using "vaccines" as a keyword. Videos in French with at least 10,000 views were identified. For each video, specific descriptive information including the opinion on vaccination was identified. To study the anti-vaccine reaction linked to a change in French policy on vaccination, the main arguments used in videos with negative opinions on vaccination uploaded in 2017 and 2018 were also collected.

RESULTS

We identified 166 videos: 120 (72.2%) were considered anti-vaccine videos and 46 (27.8%) were pro-vaccine; 92 (55%) were uploaded between 2017 and 2018. The anti-vaccine videos had been viewed 5,129,215 times and the pro-vaccine videos 2,371,048 times. The three most widely used anti-vaccination arguments were in regard to side effects (75.8%), pharmaceutical lobbying (61.3%), and the presence of adjuvants (51.6%).

CONCLUSION

Health professionals should be aware of the widely disseminated vaccination misinformation available on the Internet. Health professionals and health authorities must invest in these platforms, perhaps in collaboration with popular channels, to inform users accurately and to refute arguments put forward by anti-vaccine videos. Increasing and maintaining vaccination use is vital for vaccines to achieve success, particularly in France where vaccine hesitancy is strong.

Influenza Vaccination Experiences of Pregnant Women as a Predictor of the Intention to Become Vaccinated in Future Pregnancies in Spain

A good perception of the vaccines administered during pregnancy favors immunization coverage, which is still not optimal for the influenza vaccine. To understand the predisposition towards vaccination in future pregnancies, a study was performed that evaluated the experiences of women with the vaccine or influenza. A cross-sectional study was conducted through telephone interviews given to a total of 683 postpartum women in two health departments from the Valencia Community (Spain). This interview asked about their intention of becoming vaccinated in future pregnancies and whether they were favor or against vaccination. Most of them, 98.5% (n = 673 [95% CI: 97.6–99.4]) (p < 0.001) declared having received the systematic vaccines throughout their lives. The ones who were vaccinated against influenza, 91.9% (n = 387 [95% CI: 89.2–94.6]) (p < 0.001) manifested they would do so in future pregnancies. The probability of future non-vaccination was modeled, which was related to an unfavorable opinion towards vaccines (OR = 4.07 [95% CI: 2.01–8.24]) (p < 0.001), having suffered from influenza during pregnancy (OR = 3.84 [95% CI: 1.41–10.42]) (p < 0.05), and not having been vaccinated during previous pregnancies (OR = 38.47 [95% CI: 23.58–62.76]) (p < 0.001). Vaccination during pregnancy increases the intent of vaccination in the future.

Increasing healthcare workers' uptake of seasonal influenza vaccination in a tertiary-care pediatric hospital in Greece with a low-cost, tailor-made, multifaceted strategy

BACKGROUND

Healthcare workers' (HCW) seasonal influenza vaccination (SIV) is critical to prevent nosocomial influenza. However, HCW vaccination rates remain unacceptably low in many European institutions. A two-year three-step initiative was implemented at a tertiary-care pediatric hospital with 750 beds in Athens, Greece with the aim of increasing SIV among HCW.

METHODS

Α cross-sectional anonymous survey of HCWs was conducted during the 2015-16 influenza season with the aim to evaluate attitudes, knowledge, and specific barriers and facilitators for SIV. Stratified analysis was used to identify factors associated with no prior history of influenza vaccination. Multifaceted interventions were implemented in the 2016-2017 season. These included 1) education around influenza disease and SIV, and 2) communication of availability and opportunity (time and place) of SIV. Interventions were designed to target HCWs with the lowest SIV rates in the previous three years.

RESULTS

We achieved a 67% response rate, with 363 respondents (106 doctors, 145 nurses, 101 other hospital staff; 11 did not provide their profession). Most (64%) had not been vaccinated in the previous three years; only 14% received the vaccine annually. Non-vaccination rates were significantly higher among nurses (76%) and cleaning and food-service workers (73%) compared to doctors (40%) (P < 0.001). Protection of self, family, patients and colleagues were the most common motivations. Concerns about the safety and effectiveness of the vaccine, the belief that one does not belong to a high-risk group were the most common barriers. The interventions led to an increase in SIV uptake by the HCWs in the hospital, from 19% to 31%.

CONCLUSIONS

In a country with very low reported rates of vaccination among HCWs, a simple, low-cost, tailor-made intervention strategy can lead to an increase in SIV uptake. Stratifying data according to vaccination history may reveal a diversity of targets for improvement that might otherwise be missed.

Construction and Immunogenicity of a Novel Multivalent Vaccine Prototype Based on Conserved Influenza Virus Antigens

Influenza, an acute, highly contagious respiratory disease, remains a significant threat to public health. More effective vaccination strategies aimed at inducing broad cross-protection not only against seasonal influenza variants, but also zoonotic and emerging pandemic influenza strains are urgently needed. A number of conserved protein targets to elicit such cross-protective immunity have been under investigation, with long alpha-helix (LAH) from hemagglutinin stalk and ectodomain of matrix protein 2 ion channel (M2e) being the most studied ones. Recently, we have reported the three-dimensional structure and some practical applications of LAH expressed in Escherichia coli system (referred to as tri-stalk protein). In the present study, we investigated the immunogenicity and efficacy of a panel of broadly protective influenza vaccine prototypes based on both influenza tri-stalk and triple M2e (3M2e) antigens integrated into phage AP205 virus-like particles (VLPs). While VLPs containing the 3M2e alone induced protection against standard homologous and heterologous virus challenge in mice, only the combination of both conserved influenza antigens into a single VLP fully protected mice from a high-dose homologous H1N1 influenza infection. We propose that a combination of genetic fusion and chemical coupling techniques to expose two different foreign influenza antigens on a single particle is a perspective approach for generation of a broadly-effective vaccine candidate that could protect against the constantly emerging influenza virus strains.

Host immune response-inspired development of the influenza vaccine

Objective

To assess the current and future development of influenza vaccines.

Data Sources

PubMed searches were performed cross-referencing the keywords influenza, influenza vaccine, host immune response, correlates of protection, vaccine development, vaccine efficacy. Articles were reviewed for additional citations.

Study Selections

Articles were reviewed and selected on the basis of relevance to subject matter.

Results

In this review, we first introduce the influenza virus, its nomenclature, and the concepts of antigenic drift and shift. Second, we discuss the status of currently licensed influenza virus vaccines. We briefly focus on influenza vaccine responses beyond hemagglutination inhibition that may correlate with protection against influenza viruses of different subtypes. Third, we explain how studying host responses to influenza infection and vaccination with advanced serologic methods, B-cell receptor sequencing, and transcriptomic profiling can guide the development of improved influenza virus vaccines. Fourth, we provide 2 suggestions on how current influenza vaccines can be optimized by redirecting immune responses toward conserved viral antigens and the use of adjuvants.

Conclusion

Influenza vaccine design can benefit from novel insights obtained from the study of host responses to influenza virus infection and vaccination. Integration of the large amount of available clinical and preclinical data requires systems approaches that can elucidate novel correlates of protection and will guide further development of influenza vaccine.

Influenza vaccine effectiveness against hospitalization with laboratory-confirmed influenza in Greece: A pooled analysis across six seasons, 2013-2014 to 2018-2019

BACKGROUND

Monitoring seasonal influenza Vaccine Effectiveness (VE) is key to inform vaccination strategies and sustain uptake. Pooling data across multiple seasons increases precision and allows for subgroup analyses, providing more conclusive evidence. Our aim was to assess VE against hospitalization with laboratory-confirmed influenza in Greece over six seasons, from 2013 to 2014 to 2018-2019, using routinely collected surveillance data.

METHODS

Swab samples from hospitalized patients across the country were tested for influenza by RT-PCR. We used the test-negative design, with patients testing positive for influenza serving as cases and those testing negative serving as controls. VE was calculated as one minus the Odds Ratio (OR) for influenza vaccination, estimated by mixed-effects logistic regression and adjusted for age, sex, hospitalization type (being in intensive care or not), time from symptom onset to swabbing, and calendar time. Stratified estimates by age and hospitalization type were obtained, and also subgroup estimates by influenza type/subtype and season. Antigenic and genetic characterization of a subset of circulating influenza strains was performed.

RESULTS

A total of 3,882 test-positive cases and 5,895 test-negative controls were analyzed. Across all seasons, adjusted VE was 45.5% (95% CI: 31.6-56.6) against all influenza, 62.8% against A(H1N1)pdm09 (95% CI: 40.7-76.7), 28.2% against A(H3N2) (95% CI: 12.0-41.3) and 45.5% against influenza B (95% CI: 29.1-58.1). VE was slightly lower for patients aged 60 years and over, and similar between patients hospitalized inside or outside intensive care. Circulating A(H1N1)pdm09 and B strains were antigenically similar to the vaccine strains, whereas A(H3N2) were not.

CONCLUSION

Our results confirm the public health benefits from seasonal influenza vaccination, despite the suboptimal effectiveness against A(H3N2) strains. Continued monitoring of VE is essential, and routinely collected surveillance data can be valuable in this regard.