Vaccines for preventing influenza in the elderly

Analysis of R848 as an Adjuvant to Improve Inactivated Influenza Vaccine Immunogenicity in Elderly Nonhuman Primates

Elderly individuals are highly susceptible to developing severe outcomes as a result of influenza A virus (IAV) infection. This can be attributed to alterations that span the aged immune system, which also result in reduced responsiveness to the seasonal inactivated vaccine. Given the rapidly increasing number of individuals in this age group, it is imperative that we develop strategies that can better protect this population from IAV-associated disease. Based on our previous findings that the TLR7/8 agonist resiquimod (R848) could efficiently boost responses in the newborn, another population with decreased vaccine responsiveness, we evaluated this adjuvant in an elderly African green monkey (AGM) model. AGM aged 16-24 years old (equivalent to 64-96 in human years) were primed and boosted with inactivated A/PuertoRico/8/1934 (H1N1) (IPR8) alone or directly linked to R848 (IPR8-R848). We observed increases in the level of circulating virus-specific IgM antibody 10 days following primary vaccination in AGM that were vaccinated with IPR8-R848, but not IPR8 alone. In addition, there were significant increases in virus-specific IgG after boosting selectively in the IPR8-R848 vaccinated animals. These findings provide insights into the ability of R848 to modulate the aged immune system in the context of IAV vaccination.

Associations of statin use with 30-day adverse outcomes among 4 801 406 US Veterans with and without SARS-CoV-2: an observational cohort study

OBJECTIVE

To estimate associations of statin use with hospitalisation, intensive care unit (ICU) admission and mortality at 30 days among individuals with and without a positive test for SARS-CoV-2.

DESIGN

Retrospective cohort study.

SETTING

US Veterans Health Administration (VHA).

PARTICIPANTS

All veterans receiving VHA healthcare with ≥1 positive nasal swab for SARS-CoV-2 between 1 March 2020 and 10 March 2021 (cases; n=231 154) and a comparator group of controls comprising all veterans who did not have a positive nasal swab for SARS-CoV-2 but who did have ≥1 clinical lab test performed during the same time period (n=4 570 252).

MAIN OUTCOMES

Associations of: (1) any statin use, (2) use of specific statins or (3) low-intensity/moderate-intensity versus high-intensity statin use at the time of positive nasal swab for SARS-CoV-2 (cases) or result of clinical lab test (controls) assessed from pharmacy records with hospitalisation, ICU admission and death at 30 days. We also examined whether associations differed between individuals with and without a positive test for SARS-CoV-2.

RESULTS

Among individuals who tested positive for SARS-CoV-2, statin use was associated with lower odds of death at 30 days (OR 0.81 (95% CI 0.77 to 0.85)) but not with hospitalisation or ICU admission. Associations were similar comparing use of each specific statin to no statin. Compared with low-/moderate intensity statin use, high-intensity statin use was not associated with lower odds of ICU admission or death. Over the same period, associations of statin use with 30-day outcomes were significantly stronger among individuals without a positive test for SARS-CoV-2: hospitalisation OR 0.79 (95% CI 0.77 to 0.80), ICU admission OR 0.86 (95% CI 0.81 to 0.90) and death 0.60 (95% CI 0.58 to 0.62; p for interaction all <0.001).

CONCLUSIONS

Associations of statin use with lower adverse 30-day outcomes are weaker among individuals who tested positive for SARS-CoV-2 compared with individuals without a positive test, indicating that statins do not exert SARS-CoV-2 specific effects.

Healthcare Workers' (HCWs) attitudes towards mandatory influenza vaccination: A systematic review and meta-analysis

Influenza is a disease responsible for thousands of deaths every year. Although healthcare workers (HCWs) represent a way of contagion for patients, vaccination coverage among them is low. Mandatory vaccination has been proposed, but controversies remain. This systematic review and meta-analysis aimed to assess the acceptance of mandatory vaccination by HCWs, and to investigate associated characteristics. MEDLINE, Scopus, Embase, PsycInfo, CINAHL and Web of Science were used to search for studies assessing the topic. PRISMA statements were followed. Of the 13,457 univocal records found, 52 studies were included in the systematic review and 40 in the meta-analysis. The pooled proportion of HCWs accepting the policy was of 61% (95% CI: 53%- 68%) but with great heterogeneity between continents (from 54% in Europe to 69% in Asia) and in different professionals (from 40% in nurses to 80% in students). Vaccinated HCWs agreed more frequently with mandatory vaccination than non-vaccinated ones. More studies that consider mandatory vaccination acceptance as the main outcome are needed, but the results of this study confirm that in some settings the majority of HCWs favour mandatory vaccination. This, combined with effects that a flu epidemic could have if overlapped to pandemics with similar symptoms, requires renewed considerations on mandatory vaccination.

Cost-Effectiveness of Pediatric Influenza Vaccination in The Netherlands

OBJECTIVE

This study evaluates the cost-effectiveness of extending the Dutch influenza vaccination program for elderly and medical high-risk groups to include pediatric influenza vaccination, taking indirect protection into account.

METHODS

An age-structured dynamic transmission model was used that was calibrated to influenza-associated GP visits over 4 seasons (2010-2011 to 2013-2014). The clinical and economic impact of different pediatric vaccination strategies were compared over 20 years, varying the targeted age range, the vaccine type for children or elderly and high-risk groups. Outcome measures include averted symptomatic infections and deaths, societal costs and quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios. Costs and QALYs were discounted at 4% and 1.5% annually.

RESULTS

At an assumed coverage of 50%, adding pediatric vaccination for 2- to 17-year-olds with quadrivalent live-attenuated vaccine to the current vaccination program for elderly and medical high-groups with quadrivalent inactivated vaccine was estimated to avert, on average, 401 820 symptomatic cases and 72 deaths per year. Approximately half of averted symptomatic cases and 99% of averted deaths were prevented in other age groups than 2- to 17-year-olds due to herd immunity. The cumulative discounted 20-year economic impact was 35 068 QALYs gained and €1687 million saved, that is, the intervention was cost-saving. This vaccination strategy had the highest probability of being the most cost-effective strategy considered, dominating pediatric strategies targeting 2- to 6-year-olds or 2- to 12-year-olds or strategies with trivalent inactivated vaccine.

CONCLUSION

Modeling indicates that introducing pediatric influenza vaccination in The Netherlands is cost-saving, reducing the influenza-related disease burden substantially.

Utility of Healthcare System-Based Interventions in Improving the Uptake of Influenza Vaccination in Healthcare Workers at Long-Term Care Facilities: A Systematic Review

Healthcare workers (HCWs) in long-term care facilities (LTCFs) can represent a source of influenza infection for the elderly. While flu vaccination coverage (VC) is satisfactory in the elderly, HCWs are less likely to be vaccinated. There is no definitive evidence on which types of healthcare system-based interventions at LTCFs would be more useful in improving the vaccination uptake among HCWs. We performed a systematic review in different databases (Pubmed, Cochrane Database of Systematic Reviews, Health Evidence, Web of Science, Cinahl) to provide a synthesis of the available studies on this topic. Among the 1177 articles screened by their titles and abstracts, 27 were included in this review. Most of the studies reported multiple interventions addressed to improve access to vaccination, eliminate individual barriers, or introduce policy interventions. As expected, mandatory vaccinations seem to be the most useful intervention to increase the vaccination uptake in HCWs. However, our study suggests that better results in the vaccination uptake in HCWs were obtained by combining interventions in different areas. Educational campaigns alone could not have an impact on vaccination coverage. LTCFs represent an ideal setting to perform preventive multi-approach interventions for the epidemiological transition toward aging and chronicity.

Seasonal Incidence of Community-acquired Pneumonia: A Retrospective Study in a Tertiary Care Hospital in Kathmandu, Nepal

Introduction

Community-acquired pneumonia (CAP) is the major cause of death in adult and elderly persons with a variety of presentations. Seasonal variation in the incidence of the disease is essential for clinicians and epidemiologists who deal with such diseases. The study was aimed at analysing the clinical profile and outcomes of community-acquired pneumonia during different seasons of the year in a tertiary care hospital, Manmohan Memorial Teaching Hospital (MMTH), of Kathmandu, Nepal.

Method

The aetiology and clinical profile of 378 patients with CAP who were admitted to MMTH over a period of one year were taken into account in this retrospective cross-sectional hospital-based study. Data were retrieved from the hospital medical records section and the Department of Pathology. All patients with a primary diagnosis of CAP admitted to the hospital were included in the study. Monthly and seasonal trends, aetiology, comorbidities, and mortality rates were analysed.

Results 

Of 378 patients with CAP, 160 patients (42.3%) had associated chronic obstructive pulmonary disease (COPD), 92 patients (24.3%) had hypertension (HTN), 59 patients (15.6%) had diabetes, 12 patients (3.1%) had active pulmonary tuberculosis, seven patients (1.85%) had kidney disease, and the remaining 48 patients (12.6%) had only CAP. Seasonal variation of CAP was noted in 131 patients (35%) in the winter, 98 (26%) in autumn, 86 (23%) in spring, and 63 patients (16%) in summer seasons. None of the patients were vaccinated against influenza and pneumococcus. The most common organism isolated in CAP was Acinetobacter calcoaceticus baumannii (ACB) complex (4.7%), which was more distinguished in the winter season. The second most isolated organism was Pseudomonas aeruginosa (2.6%). The most common clinical presentation was fever (63%), followed by cough (47%) and shortness of breath (47%). Sputum culture was found to be positive in 51 cases (13.4%). Among 378 patients, 78 patients (20.6%) received treatment in the Intensive Care Unit (ICU) and the rest of the patients received treatment in the general medical ward. The mortality rate was found to be 6.6%.

Conclusion

An incidence of sputum-positive CAP was found in 51 cases (13.4%). The most common organism was ACB complex, followed by Pseudomonas aeruginosa, which were sensitive to polymyxins. Both of them were predominant in the winter and spring.

Do various personal hygiene habits protect us against influenza-like illness?

BACKGROUND

Several studies have reported an association between improvements in hand hygiene and the reductions in rates of intestinal parasitic diseases. However, only a some have addressed its link to the frequency of influenza-like illness. The current study aimed to find the correlation between personal hygiene habits and the frequency of influenza-like illness.

METHODS

A cross-sectional study targeting 3000 participants conducted in Riyadh city, Saudi Arabia. A systematic random sampling methodology was applied for participant from different part of Riyadh city using a computer generating system. The researcher first started by calling each participant. A full explanation was given to each participant in details (from the purpose of the research, consent to answer the questionnaire, to the explanation of the outcome definition). Each point of the questionnaire was explained to them to make sure they had excellent comprehension, and therefore, respond accurately. Descriptive statistics and Odds Ratio and its 95% confidence intervals were used to determine the association between frequency of influenza-like illness and the studied variables.

RESULTS

Two thousand eighty-two (69.4%) completed the questionnaire. The participants who spent 5-10 s in handwashing with soap and rubbing were at increased risk of more frequent influenza-like illness (odds ratio = 1.37, 1.08-1.75). Handwashing with soap and rubbing after handshaking is an independent protective habit against frequent influenza-like illness (adjusted OR = 0.59, 0.37-0.94).

CONCLUSION

The decrease of the frequency of influenza-like illness could be done through the following: getting the influenza vaccine annually, washing hands with soap and hand rubbing not less than 15 s after getting out of the bathroom, before and after handshaking and before eating. Soap companies should invent soaps that take less rubbing time to kill bacteria, and subsequently may maximize compliance in the community.

Heterologous Two-Dose Vaccination with Simian Adenovirus and Poxvirus Vectors Elicits Long-Lasting Cellular Immunity to Influenza Virus A in Healthy Adults

Background

T-cell responses against highly conserved influenza antigens have been previously associated with protection. However, these immune responses are poorly maintained following recovery from influenza infection and are not boosted by inactivated influenza vaccines. We have previously demonstrated the safety and immunogenicity of two viral vectored vaccines, modified vaccinia virus Ankara (MVA) and the chimpanzee adenovirus ChAdOx1 expressing conserved influenza virus antigens, nucleoprotein (NP) and matrix protein-1 (M1). We now report on the safety and long-term immunogenicity of multiple combination regimes of these vaccines in young and older adults.

Methods

We conducted a Phase I open-label, randomized, multi-center study in 49 subjects aged 18–46 years and 24 subjects aged 50 years or over. Following vaccination, adverse events were recorded and the kinetics of the T cell response determined at multiple time points for up to 18 months.

Findings

Both vaccines were well tolerated. A two dose heterologous vaccination regimen significantly increased the magnitude of pre-existing T-cell responses to NP and M1 after both doses in young and older adults. The fold-increase and peak immune responses after a single MVA-NP + M1 vaccination was significantly higher compared to ChAdOx1 NP + M1. In a mixed regression model, T-cell responses over 18 months were significantly higher following the two dose vaccination regimen of MVA/ChAdOx1 NP + M1.

Interpretation

A two dose heterologous vaccination regimen of MVA/ChAdOx1 NP + M1 was safe and immunogenic in young and older adults, offering a promising vaccination strategy for inducing long-term broadly cross-reactive protection against influenza A.

Funding Source

Medical Research Council UK, NIHR BMRC Oxford.

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Heterologous prime-boost vaccination regimens of MVA/ChAdOx1 NP+M1 are safe and immunogenic in young and older adults

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All MVA/ChAdOx1 NP+M1 regimens tested significantly increased cross-reactive T-cells

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Responses were durable and were maintained 18 months after vaccination

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The fold-increase after a single MVA-NP+M1 vaccination was significantly higher compared to ChAdOx1 NP+M1

Current seasonal influenza vaccines induce antibody responses to external glycoproteins, which are highly susceptible to the accumulation of mutations within antigenic sites, allowing escape from serological immunity conferred by prior infection or vaccination. In this phase I clinical study, we present the results of using two replication-deficient viral vectors expressing conserved influenza A antigens in four different vaccination regimens, administered at intervals of either 8 weeks or one year. We found that vaccination was safe and boosted T cell responses to influenza antigens substantially, with a further increase after the second vaccination, both in young and older adults.

Vaccines for preventing influenza in the elderly

BACKGROUND

The consequences of influenza in the elderly (those age 65 years or older) are complications, hospitalisations, and death. The primary goal of influenza vaccination in the elderly is to reduce the risk of death among people who are most vulnerable. This is an update of a review published in 2010. Future updates of this review will be made only when new trials or vaccines become available. Observational data included in previous versions of the review have been retained for historical reasons but have not been updated because of their lack of influence on the review conclusions.

OBJECTIVES

To assess the effects (efficacy, effectiveness, and harm) of vaccines against influenza in the elderly.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 11), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register; MEDLINE (1966 to 31 December 2016); Embase (1974 to 31 December 2016); Web of Science (1974 to 31 December 2016); CINAHL (1981 to 31 December 2016); LILACS (1982 to 31 December 2016); WHO International Clinical Trials Registry Platform (ICTRP; 1 July 2017); and ClinicalTrials.gov (1 July 2017).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs assessing efficacy against influenza (laboratory-confirmed cases) or effectiveness against influenza-like illness (ILI) or safety. We considered any influenza vaccine given independently, in any dose, preparation, or time schedule, compared with placebo or with no intervention. Previous versions of this review included 67 cohort and case-control studies. The searches for these trial designs are no longer updated.

DATA COLLECTION AND ANALYSIS

Review authors independently assessed risk of bias and extracted data. We rated the certainty of evidence with GRADE for the key outcomes of influenza, ILI, complications (hospitalisation, pneumonia), and adverse events. We have presented aggregate control group risks to illustrate the effect in absolute terms. We used them as the basis for calculating the number needed to vaccinate to prevent one case of each event for influenza and ILI outcomes.

MAIN RESULTS

We identified eight RCTs (over 5000 participants), of which four assessed harms. The studies were conducted in community and residential care settings in Europe and the USA between 1965 and 2000. Risk of bias reduced our certainty in the findings for influenza and ILI, but not for other outcomes.Older adults receiving the influenza vaccine may experience less influenza over a single season compared with placebo, from 6% to 2.4% (risk ratio (RR) 0.42, 95% confidence interval (CI) 0.27 to 0.66; low-certainty evidence). We rated the evidence as low certainty due to uncertainty over how influenza was diagnosed. Older adults probably experience less ILI compared with those who do not receive a vaccination over the course of a single influenza season (3.5% versus 6%; RR 0.59, 95% CI 0.47 to 0.73; moderate-certainty evidence). These results indicate that 30 people would need to be vaccinated to prevent one person experiencing influenza, and 42 would need to be vaccinated to prevent one person having an ILI.The study providing data for mortality and pneumonia was underpowered to detect differences in these outcomes. There were 3 deaths from 522 participants in the vaccination arm and 1 death from 177 participants in the placebo arm, providing very low-certainty evidence for the effect on mortality (RR 1.02, 95% CI 0.11 to 9.72). No cases of pneumonia occurred in one study that reported this outcome (very low-certainty evidence). No data on hospitalisations were reported. Confidence intervaIs around the effect of vaccines on fever and nausea were wide, and we do not have enough information about these harms in older people (fever: 1.6% with placebo compared with 2.5% after vaccination (RR 1.57, 0.92 to 2.71; moderate-certainty evidence)); nausea (2.4% with placebo compared with 4.2% after vaccination (RR 1.75, 95% CI 0.74 to 4.12; low-certainty evidence)).

AUTHORS' CONCLUSIONS

Older adults receiving the influenza vaccine may have a lower risk of influenza (from 6% to 2.4%), and probably have a lower risk of ILI compared with those who do not receive a vaccination over the course of a single influenza season (from 6% to 3.5%). We are uncertain how big a difference these vaccines will make across different seasons. Very few deaths occurred, and no data on hospitalisation were reported. No cases of pneumonia occurred in one study that reported this outcome. We do not have enough information to assess harms relating to fever and nausea in this population.The evidence for a lower risk of influenza and ILI with vaccination is limited by biases in the design or conduct of the studies. Lack of detail regarding the methods used to confirm the diagnosis of influenza limits the applicability of this result. The available evidence relating to complications is of poor quality, insufficient, or old and provides no clear guidance for public health regarding the safety, efficacy, or effectiveness of influenza vaccines for people aged 65 years or older. Society should invest in research on a new generation of influenza vaccines for the elderly.

Vaccinations in Older Adults

Vaccines are important for preventing infections in adults aged ≥65 years. Older adults are at increased risk for complications from vaccine-preventable illnesses due to age-associated changes in immune function and chronic medical comorbidities. Vaccination rates for older adults remain low despite widely accepted practice guidelines. Recommended vaccinations for older adults include (1) influenza; (2) pneumococcal; (3) herpes zoster; (4) tetanus, diphtheria, pertussis; and (5) hepatitis B. Cost influences vaccination rates in older adults.

The Importance of Frailty in the Assessment of Influenza Vaccine Effectiveness Against Influenza-Related Hospitalization in Elderly People

Background

Influenza is an important cause of morbidity and mortality among older adults. Even so, effectiveness of influenza vaccine for older adults has been reported to be lower than for younger adults, and the impact of frailty on vaccine effectiveness (VE) and outcomes is uncertain. We aimed to study VE against influenza hospitalization in older adults, focusing on the impact of frailty.

Methods

We report VE of trivalent influenza vaccine (TIV) in people ≥65 years of age hospitalized during the 2011-2012 influenza season using a multicenter, prospective, test-negative case-control design. A validated frailty index (FI) was used to measure frailty.

Results

Three hundred twenty cases and 564 controls (mean age, 80.6 and 78.7 years, respectively) were enrolled. Cases had higher baseline frailty than controls (P = .006). In the fully adjusted model, VE against influenza hospitalization was 58.0% (95% confidence interval [CI], 34.2%-73.2%). The contribution of frailty was important; adjusting for frailty alone yielded a VE estimate of 58.7% (95% CI, 36.2%-73.2%). VE was 77.6% among nonfrail older adults and declined as frailty increased.

Conclusions

Despite commonly held views that VE is poor in older adults, we found that TIV provided good protection against influenza hospitalization in older adults who were not frail, though VE diminished as frailty increased.

Clinical Trials Registration

NCT01517191.

Perspectives on benefit-risk decision-making in vaccinology: Conference report

Benefit/risk (B/R) assessment methods are increasingly being used by regulators and companies as an important decision-making tool and their outputs as the basis of communication. B/R appraisal of vaccines, as compared with drugs, is different due to their attributes and their use. For example, vaccines are typically given to healthy people, and, for some vaccines, benefits exist both at the population and individual level. For vaccines in particular, factors such as the benefit afforded through herd effects as a function of vaccine coverage and consequently impact the B/R ratio, should also be taken into consideration and parameterized in B/R assessment models. Currently, there is no single agreed methodology for vaccine B/R assessment that can fully capture all these aspects. The conference "Perspectives on Benefit-Risk Decision-making in Vaccinology," held in Annecy (France), addressed these issues and provided recommendations on how to advance the science and practice of B/R assessment of vaccines and vaccination programs.

The Clinical Impact and Cost Effectiveness of Quadrivalent Versus Trivalent Influenza Vaccination in Finland

BACKGROUND

Trivalent influenza vaccines encompass one influenza B lineage; however, predictions have been unreliable on which of two antigenically distinct circulating lineages will dominate. Quadrivalent seasonal influenza vaccines contain strains from both lineages. This analysis assesses the cost effectiveness of switching from trivalent inactivated influenza vaccination (TIV) in Finland to quadrivalent vaccination, using inactivated (QIV) or live-attenuated (Q-LAIV) vaccines.

METHODS

A transmission model simulated the dynamics of influenza infection while accounting for indirect (herd) protection. Prior distributions for key transmission parameters were repeatedly sampled and simulations that fitted the available information on influenza in Finland were recorded. The resulting posterior parameter distributions were used in a probabilistic sensitivity analysis in which economic parameters were sampled, simultaneously encompassing uncertainty in the transmission and economic parameters. The cost effectiveness of a range of trivalent and quadrivalent vaccine policies over a 20-year time horizon was assessed from both a societal and payer perspective in 2014 Euros.

RESULTS

The simulated temporal incidence pattern of symptomatic infections corresponded well with case surveillance data. A switch from the current TIV to Q-LAIV in children (2 to <18 years) and to QIV in other ages was estimated to annually avert approximately 76,100 symptomatic infections (95 % range 36,700-146,700), 11,500 primary care consultations (6100-20,000), 540 hospitalisations (240-1180), and 72 deaths (32-160), and was cost-saving relative to TIV (€374 million averted [€161-€752], in 2014 Euros, discounted at 3 %). This scenario had the highest probability of being the most cost-effective scenario considered.

CONCLUSIONS

This analysis demonstrates that quadrivalent vaccination is expected to be highly cost effective, reducing the burden of influenza-related disease.

Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics - a systematic literature review

AIM

The evidence needed for tropical countries to take informed decisions on influenza vaccination is scarce. This article reviews policy, availability, use and effectiveness of seasonal influenza vaccine in tropical and subtropical countries.

METHOD

Global health databases were searched in three thematic areas - policy, availability and protective benefits in the context of human seasonal influenza vaccine in the tropics and subtropics. We excluded studies on monovalent pandemic influenza vaccine, vaccine safety, immunogenicity and uptake, and disease burden.

RESULTS

Seventy-four countries in the tropics and subtropics representing 60% of the world's population did not have a national vaccination policy against seasonal influenza. Thirty-eight countries used the Northern Hemisphere and 21 countries the Southern Hemisphere formulation. Forty-six countries targeted children and 57 targeted the elderly; though, the age cut-offs varied. Influenza vaccine supply increased twofold in recent years. However, coverage remained lower than five per 1000 population. Vaccine protection against laboratory-confirmed influenza in the tropics ranged from 0% to 42% in the elderly, 20-77% in children and 50-59% in healthy adults. Vaccinating pregnant women against seasonal influenza prevented laboratory-confirmed influenza in both mothers (50%) and their infants <6 months (49-63%).

CONCLUSION

Guidelines on vaccine composition, priority risk groups and vaccine availability varied widely. The evidence on vaccine protection was scarce. Countries in the tropics and subtropics need to strengthen and expand their evidence-base required for making informed decisions on influenza vaccine introduction and expansion, and how much benefit to expect.

The success of microneedle-mediated vaccine delivery into skin

Microneedles (MNs) are designed to specifically target the outermost, skin barrier layer, the stratum corneum, creating transient pathways for minimally invasive transcutaneous delivery. It is reported that MNs can facilitate delivery without stimulating the pain receptors or damaging blood vessels that lie beneath, thus being perceived as painless and associated with reduced bleeding. This immunocompetence of the skin, coupled with its ease of access, makes this organ an attractive vaccination site. The purpose of this review was to collate primary scientific literature pertaining to MN-mediated in vivo vaccination programmes. A total of 62 original research articles are presented, compiling vaccination strategies in 6 different models (mouse, rat, guinea pig, rabbit, pig, macaque and human). Vaccines tested span a wide range of viral, bacterial and protozoan pathogens and includes 7 of the 13 vaccine-preventable diseases, as defined by the WHO. This review highlights the paucity of available clinical trial data. MN-delivered vaccines have demonstrated safety and immunogenicity in pre-clinical models and boast desirable attributes such as painless administration, thermostability, dose-sparing capacity and the potential for self-administration. These advantages should contribute to enhanced global vaccine access.

Hygiene Behaviors Associated with Influenza-Like Illness among Adults in Beijing, China: A Large, Population-Based Survey

The objective of this study was to identify possible hygiene behaviors associated with the incidence of ILI among adults in Beijing. In January 2011, we conducted a multi-stage sampling, cross-sectional survey of adults living in Beijing using self-administered anonymous questionnaires. The main outcome variable was self-reported ILI within the past year. Multivariate logistic regression was used to identify factors associated with self-reported ILI. A total of 13003 participants completed the questionnaires. 6068 (46.7%) of all participants reported ILI during the past year. After adjusting for demographic characteristics, the variables significantly associated with a lower likelihood of reporting ILI were regular physical exercise (OR 0.80; 95% CI 0.74–0.87), optimal hand hygiene (OR 0.87; 95% CI 0.80–0.94), face mask use when going to hospitals (OR 0.87; 95% CI 0.80–0.95), and not sharing of towels and handkerchiefs (OR 0.68; 95% CI 0.63–0.73). These results highlight that personal hygiene behaviors were potential preventive factors against the incidence of ILI among adults in Beijing, and future interventions to improve personal hygiene behaviors are needed in Beijing.

Aging-dependent alterations in gene expression and a mitochondrial signature of responsiveness to human influenza vaccination

To elucidate gene expression pathways underlying age-associated impairment in influenza vaccine response, we screened young (age 21-30) and older (age ≥65) adults receiving influenza vaccine in two consecutive seasons and identified those with strong or absent response to vaccine, including a subset of older adults meeting criteria for frailty. PBMCs obtained prior to vaccination (Day 0) and at day 2 or 4, day 7 and day 28 post-vaccine were subjected to gene expression microarray analysis. We defined a response signature and also detected induction of a type I interferon response at day 2 and a plasma cell signature at day 7 post-vaccine in young responders. The response signature was dysregulated in older adults, with the plasma cell signature induced at day 2, and was never induced in frail subjects (who were all non-responders). We also identified a mitochondrial signature in young vaccine responders containing genes mediating mitochondrial biogenesis and oxidative phosphorylation that was consistent in two different vaccine seasons and verified by analyses of mitochondrial content and protein expression. These results represent the first genome-wide transcriptional profiling analysis of age-associated dynamics following influenza vaccination, and implicate changes in mitochondrial biogenesis and function as a critical factor in human vaccine responsiveness.

Vaccination in the elderly: what can be recommended?

The age-associated increased susceptibility to infectious disease would suggest that vaccination should be a route to promote healthy aging and keep our seniors autonomous and independent. While vaccination represents a cost-effective and efficient strategy at community level, the ability of the immune system to mount a protective immune response is still unpredictable at the level of the individual. Thus, at a similar age, some individuals, including the elderly, might still be 'good' responders while some other, even younger, would definitely fail to mount a protective response. In this review, the current burden of vaccine-preventable diseases in the aging and aged population will be detailed with the aim to identify the ideal vaccine candidates over the age of 50 years. This article will conclude with potential strategies to reduce, as best as possible, this burden and the imperative need to overcome barriers in extending current vaccine coverage towards to a lifelong vaccine schedule.

The impact of vaccination on influenza-related respiratory failure and mortality in hospitalized elderly patients over the 2013-2014 season

BACKGROUND

Seasonal Influenza ("the flu") is a respiratory illness caused by influenza viruses. Yearly influenza vaccination is considered to be protective against illness and/or severity of illness and is recommended by CDC for all individuals > 6 months of age. However, the effectiveness of influenza vaccine in older individuals has come under question.

OBJECTIVES

To describe the clinical characteristics and treatment outcomes of patients admitted to an academic tertiary care Veterans Administration hospital with influenza during the 2013-2014 influenza season and determine the impact, if any, of prior influenza vaccination upon patient outcomes.

METHODS

Medical electronic records were searched for all patients admitted to the Little Rock Veterans Administration Hospital with proven influenza during the 2013-2014 influenza season. Cohorts of vaccinated and non-vaccinated patients were then compared to determine the impact of prior influenza vaccination upon respiratory-failure and mortality.

RESULTS

Seventy patients met selection criteria. Mean age was 66 years. Sixty-four (91%) patients had at least one underlying co-morbid condition; these conditions included COPD, congestive heart failure, diabetes, and cancer. 60/70 (85%) tested positive for Influenza A, and 43 tested positive for H1N1. Oseltamivir was initiated in 55 (78%) patients. Forty-four percent of the patients had been vaccinated. When separated by vaccination status, those who had been vaccinated had higher rates of ICU admission, need for mechanical or non-invasive ventilation, and mortality. All but mortality reached statistical significance.

CONCLUSION

The data suggest that there was no protective effect from prior vaccination in preventing hospital admission, respiratory failure, and mortality in this population of older men admitted to the hospital with influenza.

Prolonged proinflammatory cytokine production in monocytes modulated by interleukin 10 after influenza vaccination in older adults

We evaluated in vivo innate immune responses in monocyte populations from 67 young (aged 21-30 years) and older (aged ≥65 years) adults before and after influenza vaccination. CD14(+)CD16(+) inflammatory monocytes were induced after vaccination in both young and older adults. In classical CD14(+)CD16(-) and inflammatory monocytes, production of tumor necrosis factor α and interleukin 6, as measured by intracellular staining, was strongly induced after vaccination. Cytokine production was strongly associated with influenza vaccine antibody response; the highest levels were found as late as day 28 after vaccination in young subjects and were substantially diminished in older subjects. Notably, levels of the anti-inflammatory cytokine interleukin 10 (IL-10) were markedly elevated in monocytes from older subjects before and after vaccination. In purified monocytes, we found age-associated elevation in phosphorylated signal transducer and activator of transcription-3, and decreased serine 359 phosphorylation of the negative IL-10 regulator dual-specificity phosphatase 1. These findings for the first time implicate dysregulated IL-10 production in impaired vaccine responses in older adults.

Socioeconomic impact of seasonal (epidemic) influenza and the role of over-the-counter medicines

The substantial economic impact of influenza on society results primarily from lost work time and reduced productivity of patients and caregivers and increased use of medical resources. Additionally, since the 1980s, aging of the US population has meant rising influenza-related morbidity and mortality. According to the most current published data on this topic, in 2003 the total economic burden of influenza epidemics in the USA across all age groups was US$87.1 billion. As of February 2013, overall vaccine effectiveness for the 2012/2013 season was estimated to be 56 %. The Centers for Disease Control and Prevention's National Center for Immunization and Respiratory Diseases has concluded that more effective vaccines and vaccination strategies are needed. Moderate efficacy of the influenza vaccine, continued questions regarding the value of treatment with antivirals, and a growing self-care movement have led to increased use of over-the-counter (OTC) medicines, which play a vital role in managing symptoms associated with mild to moderate influenza and provide an estimated US$102 billion in annual savings for the US healthcare system. A primary benefit to society of using OTC medicines to manage influenza is decreased use of the healthcare system, thereby mitigating the socioeconomic burden of influenza. Considering the stresses placed on the US healthcare system and the substantial productivity losses resulting from seasonal influenza as well as the growing self-care movement, OTC medicines will play an important role in the course of future influenza epidemics.

Big Data Usage Patterns in the Health Care Domain: A Use Case Driven Approach Applied to the Assessment of Vaccination Benefits and Risks. Contribution of the IMIA Primary Healthcare Working Group

BACKGROUND

Generally benefits and risks of vaccines can be determined from studies carried out as part of regulatory compliance, followed by surveillance of routine data; however there are some rarer and more long term events that require new methods. Big data generated by increasingly affordable personalised computing, and from pervasive computing devices is rapidly growing and low cost, high volume, cloud computing makes the processing of these data inexpensive.

OBJECTIVE

To describe how big data and related analytical methods might be applied to assess the benefits and risks of vaccines.

METHOD

We reviewed the literature on the use of big data to improve health, applied to generic vaccine use cases, that illustrate benefits and risks of vaccination. We defined a use case as the interaction between a user and an information system to achieve a goal. We used flu vaccination and pre-school childhood immunisation as exemplars.

RESULTS

We reviewed three big data use cases relevant to assessing vaccine benefits and risks: (i) Big data processing using crowdsourcing, distributed big data processing, and predictive analytics, (ii) Data integration from heterogeneous big data sources, e.g. the increasing range of devices in the "internet of things", and (iii) Real-time monitoring for the direct monitoring of epidemics as well as vaccine effects via social media and other data sources.

CONCLUSIONS

Big data raises new ethical dilemmas, though its analysis methods can bring complementary real-time capabilities for monitoring epidemics and assessing vaccine benefit-risk balance.

Costs and benefits of influenza vaccination: more evidence, same challenges

Seasonal influenza vaccination coverage in most EU/EEA remains suboptimal. Providers’ and users’ confidence in influenza vaccines is undermined by reports of moderate to low vaccine effectiveness and by the lack of solid evidence on disease burden. A study from Preaud and co. indicates that even with current levels of vaccine effectiveness, increasing vaccination coverage would significantly reduce disease burden and health cost. The results of the study should be interpreted cautiously because some of the assumptions are not generalizable or are imprecise, especially those on vaccine coverage, disease burden and health cost. Increasing vaccination coverage in EU/EEA countries is very challenging. Multifaceted approaches and country specific strategies are needed to address vaccine hesitancy in health care workers and in the population, and to manage organisational and financial obstacles. One key element for increasing vaccination coverage is the development of better influenza vaccines, e.g. vaccines that are more effective, provide longer lasting immunity and do not require annual administration. Vaccine producers should consider this as the highest research priority in the field of influenza vaccine development.

A cross-sectional study to investigate pneumococcal vaccination in the elderly in a low income county: patient knowledge, awareness, and attitudes of vaccination and prevalence rates by socioeconomic status

BACKGROUND

Pneumonia represents the leading cause of infection-related death and the fifth cause of overall mortality, in the elderly. With increasing age, the human immune system undergoes characteristic changes which lead to increased incidence and severity of infectious diseases and to insufficient protection following vaccination as antibody response of elderly vaccines are weaker and decline faster.

OBJECTIVE

Knowledge and Attitude toward Pneumonia and its Vaccination in elderly patients.

RESULT

Among low SES, 54.9% (549/1000) while from high SES, 91.8% (918) responded that they had heard about pneumonia before (P<0.05). 79.5% (795/1000) patients of high SES had heard about pneumococcal vaccination while only 28.8% (288/1000) patients from low SES had heard about pneumococcal vaccine. Only 2.3% of low SES patients were immunized for pneumococcal vaccine while 16.5% high SES patients were vaccinated. Reported reason for not being immunized were; did not hear, no body advised, vaccine is too expensive, and ignored thinking it is not necessary.

METHOD

We conducted a cross-sectional study on 2000 elderly patients who were admitted in medicine and surgery wards of Civil Hospital Karachi and Aga Khan University Hospital Karachi from the period of October to December 2012 to determine their knowledge and attitude toward pneumonia and its vaccination in elderly. Study group was divided into low and high socio-economic status on the basis of patients coming to government Hospital i.e., civil hospital and private hospital i.e., Aga khan hospital. Data was collected through convenient sampling technique. Exclusion criteria were patients below 60 years and those who didn't give consent to be part of study.

CONCLUSION

Aside from introducing public awareness program about elderly vaccination at state level, free of cost vaccination of elderly individuals should be done.

Tailored vaccines targeting the elderly using whole inactivated influenza vaccines bearing cytokine immunomodulators

Influenza and its complications disproportionately affect the elderly, leading to high morbidity and mortality in this ever-increasing population. Despite widespread vaccination efforts, the current influenza vaccines are less effective in the elderly; hence newer vaccine strategies are needed to improve their efficacy in this age group. We have previously shown that co-presentation of cytokines on the surface of inactivated influenza virus particles affords better protection from lethal homotypic viral challenge in young adult mice than conventional non-adjuvanted whole inactivated vaccine. Here, we determined the efficacy of these vaccine formulations in Balb/c mice "aged" to 17 months ("aged mice") along with the addition of a membrane-bound interleukin-12 (IL-12) vaccine formulation. Our investigations found that a single low-dose intramuscular vaccination with inactivated whole influenza vaccine co-presenting IL-12 was sufficient to provide enhanced protection from subsequent influenza challenge as compared with non-adjuvanted whole inactivated vaccine. Our results indicate that incorporation of cytokines such as IL-12 in a membrane-bound formulation in whole inactivated vaccine may provide a means to lower the vaccine dose while eliciting enhanced protective responses in the elderly, an age group that responds poorly to current vaccination regimens.

The burden of influenza in England by age and clinical risk group: a statistical analysis to inform vaccine policy

OBJECTIVES

To assess the burden of influenza by age and clinical status and use this to inform evaluations of the age and risk-based influenza vaccination policy in the United Kingdom.

METHODS

Weekly laboratory reports for influenza and 7 other respiratory pathogens were extracted from the national database and used in a regression model to estimate the proportion of acute respiratory illness outcomes attributable to each pathogen.

RESULTS

Influenza accounted for ∼10% of the attributed respiratory admissions and deaths in hospital. Healthy children under five had the highest influenza admission rate (1.9/1000). The presence of co-morbidities increased the admission rate by 5.7 fold for 5-14 year olds (from 0.1 to 0.56/1000), the relative risk declining to 1.8 fold in 65+ year olds (from 0.46 to 0.84/1000). The majority (72%) of influenza-attributable deaths in hospital occurred in 65+ year olds with co-morbidities. Mortality in children under 15 years was low with around 12 influenza-attributable deaths in hospital per year in England; the case fatality rate was substantially higher in risk than non-risk children. Infants under 6 months had the highest consultation and admission rates, around 70/1000 and 3/1000 respectively.

CONCLUSIONS

Additional strategies are needed to reduce the remaining morbidity and mortality in the high-risk and elderly populations, and to protect healthy children currently not offered the benefits of vaccination.

Correlation between human leukocyte antigen class II alleles and HAI titers detected post-influenza vaccination

Influenza is a major cause of morbidity and mortality. Despite vaccination, many elderly recipients do not develop a protective antibody response. To determine whether Human Leukocyte Antigen (HLA) alleles modulate seroprotection to influenza, a cohort of HLA class II-typed high-risk vaccine recipients was investigated. Haemagglutinin inhibition (HAI) titres were measured 14–40 days post-subunit vaccination. Seroprotection was defined as HAI titres reaching 40 or greater for all three vaccine strains. HLA-DRB1*04∶01 and HLA-DPB1*04∶01 alleles were detected at higher frequencies in seroprotected compared with non-seroprotected individuals. Thus, the presence of certain HLA class II alleles may determine the magnitude of antibody responses to influenza vaccination.

Influenza vaccine effectiveness against hospitalisation with confirmed influenza in the 2010-11 seasons: a test-negative observational study

Immunisation programs are designed to reduce serious morbidity and mortality from influenza, but most evidence supporting the effectiveness of this intervention has focused on disease in the community or in primary care settings. We aimed to examine the effectiveness of influenza vaccination against hospitalisation with confirmed influenza. We compared influenza vaccination status in patients hospitalised with PCR-confirmed influenza with patients hospitalised with influenza-negative respiratory infections in an Australian sentinel surveillance system. Vaccine effectiveness was estimated from the odds ratio of vaccination in cases and controls. We performed both simple multivariate regression and a stratified analysis based on propensity score of vaccination. Vaccination status was ascertained in 333 of 598 patients with confirmed influenza and 785 of 1384 test-negative patients. Overall estimated crude vaccine effectiveness was 57% (41%, 68%). After adjusting for age, chronic comorbidities and pregnancy status, the estimated vaccine effectiveness was 37% (95% CI: 12%, 55%). In an analysis accounting for a propensity score for vaccination, the estimated vaccine effectiveness was 48.3% (95% CI: 30.0, 61.8%). Influenza vaccination was moderately protective against hospitalisation with influenza in the 2010 and 2011 seasons.

Influenza vaccination coverage rates among adults before and after the 2009 influenza pandemic and the reasons for non-vaccination in Beijing, China: a cross-sectional study

Background

To optimize the vaccination coverage rates in the general population, the status of coverage rates and the reasons for non-vaccination need to be understood. Therefore, the objective of this study was to assess the changes in influenza vaccination coverage rates in the general population before and after the 2009 influenza pandemic (2008/2009, 2009/2010, and 2010/2011 seasons), and to determine the reasons for non-vaccination.

Methods

In January 2011 we conducted a multi-stage sampling, retrospective, cross-sectional survey of individuals in Beijing who were ≥ 18 years of age using self-administered, anonymous questionnaires. The questionnaire consisted of three sections: demographics (gender, age, educational level, and residential district name); history of influenza vaccination in the 2008/2009, 2009/2010, and 2010/2011 seasons; and reasons for non-vaccination in all three seasons. The main outcome was the vaccination coverage rate and vaccination frequency. Differences among the subgroups were tested using a Pearson’s chi-square test. Multivariate logistic regression was used to determine possible determinants of influenza vaccination uptake.

Results

A total of 13002 respondents completed the questionnaires. The vaccination coverage rates were 16.9% in 2008/2009, 21.8% in 2009/2010, and 16.7% in 2010/2011. Compared to 2008/2009 and 2010/2011, the higher rate in 2009/2010 was statistically significant (χ²=138.96, p<0.001), and no significant difference existed between 2008/2009 and 2010/2011 (χ²=1.296, p=0.255). Overall, 9.4% of the respondents received vaccinations in all three seasons, whereas 70% of the respondents did not get a vaccination during the same period. Based on multivariate analysis, older age and higher level of education were independently associated with increased odds of reporting vaccination in 2009/2010 and 2010/2011. Among participants who reported no influenza vaccinations over the previous three seasons, the most commonly reported reason for non-vaccination was ‘I don’t think I am very likely to catch the flu’ (49.3%).

Conclusions

Within the general population of Beijing the vaccination coverage rates were relatively low and did not change significantly after the influenza pandemic. The perception of not expecting to contract influenza was the predominant barrier to influenza vaccination. Further measures are needed to improve influenza vaccination coverage.

AS03-adjuvanted versus non-adjuvanted inactivated trivalent influenza vaccine against seasonal influenza in elderly people: a phase 3 randomised trial

BACKGROUND

We aimed to compare AS03-adjuvanted inactivated trivalent influenza vaccine (TIV) with non-adjuvanted TIV for seasonal influenza prevention in elderly people.

METHODS

We did a randomised trial in 15 countries worldwide during the 2008-09 (year 1) and 2009-10 (year 2) influenza seasons. Eligible participants aged at least 65 years who were not in hospital or bedridden and were without acute illness were randomly assigned (1:1) to receive either AS03-adjuvanted TIV or non-adjuvanted TIV. Randomisation was done in an internet-based system, with a blocking scheme and stratification by age (65-74 years and 75 years or older). Participants were scheduled to receive one vaccine in each year, and remained in the same group in years 1 and 2. Unmasked personnel prepared and gave the vaccines, but participants and individuals assessing any study endpoint were masked. The coprimary objectives were to assess the relative efficacy of the vaccines and lot-to-lot consistency of the AS03-adjuvanted TIV (to be reported elsewhere). For the first objective, the primary endpoint was relative efficacy of the vaccines for prevention of influenza A (excluding A H1N1 pdm09) or B, or both, that was confirmed by PCR analysis in year 1 (lower limit of two-sided 95% CI had to be greater than zero to establish superiority). From Nov 15, to April 30, in both years, participants were monitored by telephone or site contact and home visits every week or 2 weeks to identify cases of influenza-like illness. After onset of suspected cases, we obtained nasal and throat swabs to identify influenza RNA with real-time PCR. Efficacy analyses were done per protocol. This trial is registered with ClinicalTrials.gov, number NCT00753272.

FINDINGS

We enrolled 43 802 participants, of whom 21 893 were assigned to and received the AS03-adjuvanted TIV and 21 802 the non-adjuvanted TIV in year 1. In the year 1 efficacy cohort, fewer participants given AS03-adjuvanted than non-adjuvanted TIV were infected with influenza A or B, or both (274 [1·27%, 95% CI 1·12-1·43] of 21 573 vs 310 [1·44%, 1·29-1·61] of 21 482; relative efficacy 12·11%, 95% CI -3·40 to 25·29; superiority not established). Fewer participants in the year 1 efficacy cohort given AS03-adjuvanted TIV than non-adjuvanted TIV were infected with influenza A (224 [1·04%, 95% CI 0·91-1·18] vs 270 [1·26, 1·11-1·41]; relative efficacy 17·53%, 95% CI 1·55-30·92) and influenza A H3N2 (170 [0·79, 0·67-0·92] vs 205 [0·95, 0·83-1·09]; post-hoc analysis relative efficacy 22·0%, 95% CI 5·68-35·49).

INTERPRETATION

AS03-adjuvanted TIV has a higher efficacy for prevention of some subtypes of influenza than does a non-adjuvanted TIV. Future influenza vaccine studies in elderly people should be based on subtype or lineage-specific endpoints.

FUNDING

GlaxoSmithKline Biologicals SA.

Pneumonia immunization in older adults: review of vaccine effectiveness and strategies

Vaccination remains the primary preventive strategy in the elderly against Streptococcus pneumoniae and influenza infections. The effectiveness of this strategy in preventing pneumonia has been in doubt despite the increase in vaccination coverage among older adults. Randomized controlled trials (RCTs) and observational studies aimed at determining clinical outcomes and immune response following pneumococcal vaccination have yielded conflicting results. The protective efficacy of pneumococcal vaccination against pneumonia in older adults has not been firmly established due to a lack of RCTs specifically examining patients ≥ 65 years of age. Similarly, the reported benefits of influenza vaccination have been derived from observational data. The assessment of clinical benefit from influenza vaccination in the elderly population is complicated by varying cohorts, virulence of the influenza strain, and matching of vaccine and circulating viral strains. The presence of selection bias and use of nonspecific end points in these studies make the current evidence inconclusive in terms of overall benefit. The development of more immunogenic vaccines through new formulations or addition of adjuvants holds the promise of revolutionizing delivery and improving efficacy. Dismantling existing barriers through education, providing technology assistance predominantly to developing countries, and establishing clear regulatory guidance on pathways for approval are necessary to ensure timely production and equitable distribution.

Implementing an influenza vaccination programme for adults aged ≥65 years in Poland: a cost-effectiveness analysis

BACKGROUND AND OBJECTIVES

Influenza is a common respiratory disease occurring in seasonal patterns, and may lead to severe complications in frail populations such as the elderly. In Poland, influenza vaccination is recommended for people aged ≥65 years; however the vaccine coverage rate in the elderly is very low. The fact that influenza vaccine is neither reimbursed by the National Health Insurance (Narodowy Fundusz Zdrowia [NFZ]) nor financed via a National Immunization Program (NIP) could be a reason for the low coverage rate. This study assessed the cost effectiveness of the full reimbursement of an influenza vaccination programme in Poland for people aged ≥65 years.

METHODS

A decision-analytic model was developed to compare costs and outcomes associated with the current situation in which influenza vaccination is not reimbursed and a new situation in which it would be fully covered by the NFZ. The model was parameterized to Poland using data from the literature and from the Central Statistic Office of Poland. Within the elderly population, 50% were considered to be at high risk of influenza complications. An influenza attack rate of 3.5% was used for calculation purposes. Influenza-associated hospitalizations and death rates were estimated at 439.9 per 100 000 person-years and 79.1 per 100 000 person-years, respectively. Cost estimates were derived from a cost study conducted in Poland. Costs are presented in Polish Zloty (PLN) [2009 mean exchange rate: 1 PLN = €0.232]. Only direct medical costs were included to fit to the NFZ perspective. To reflect the seasonality of influenza, a time horizon of 1 year was chosen. Life-years and quality-adjusted life-years (QALYs) accumulated over future years were discounted at a rate of 5% as recommended by Polish guidelines. Deterministic and probabilistic sensitivity analyses were conducted.

RESULTS

In Poland, the introduction of the public funding of influenza vaccination for people aged ≥65 years would cost PLN 79 million when an increase in coverage rate from 13.5% to 40% is assumed. 23 900 cases of influenza, 1777 hospitalizations and 548 premature deaths would be averted each year due to the influenza vaccination programme. Fifty-seven persons would need to be vaccinated to prevent one case of influenza. To prevent one hospitalization and one death due to influenza, 842 and 2809 individuals would need to be vaccinated, respectively. The new strategy would be very cost effective compared with the current situation with an incremental cost-effectiveness ratio (ICER) of PLN26 118/QALY, which is below the 2009 yearly gross domestic product (GDP) per capita. Deterministic sensitivity analyses demonstrated that the most influential variables for the ICER were vaccine efficacy against death, excess hospitalization rate, utility norms, influenza attack rate, vaccine efficacy against hospitalization, and discount rates. All ICERs computed were below the threshold of 3 GDP per capita. From the probabilistic analysis, the proposed new influenza vaccination programme, if implemented, was predicted to be cost effective from the NFZ perspective with a probability of 100%, given the same threshold.

CONCLUSION

Implementing a vaccination programme in Poland in which influenza vaccination would be fully reimbursed by the NFZ for people aged ≥65 years would be a very cost-effective strategy.

Vaccines for the elderly

Vaccination is the most efficient strategy to prevent infectious disease. The increased vulnerability to infection of the elderly makes them a particularly important target population for vaccination. However, most vaccines are less immunogenic and efficient in the elderly because of age-related changes in the immune system. Vaccination against influenza, Streptococcus pneumoniae and varicella zoster virus is recommended for the elderly in many countries. Various strategies such as the use of adjuvants and novel administration routes are pursued to improve influenza vaccination for the elderly and recent developments in the field of pneumococcal vaccination led to the licensure of protein-conjugated polysaccharide vaccines containing up to 13 serotypes. As antibody titres are generally lower in the elderly and-particularly for inactivated vaccines-decline fast in the elderly, regular booster immunizations, for example against tetanus, diphtheria and, in endemic areas, tick-borne encephalitis, are essential during adulthood to ensure protection of the elderly. With increasing health and travel opportunities in old age the importance of travel vaccines for persons over the age of 60 is growing. However, little is known about immunogenicity and efficacy of travel vaccines in this age group. Despite major advances in the field of vaccinology over the last decades, there are still possibilities for improvement concerning vaccines for the elderly. Novel approaches, such as viral vectors for antigen delivery, DNA-based vaccines and innovative adjuvants, particularly toll-like receptor agonists, will help to achieve optimal protection against infectious diseases in old age.

The potential economic value of a 'universal' (multi-year) influenza vaccine

BACKGROUND

Limitations of the current annual influenza vaccine have led to ongoing efforts to develop a 'universal' influenza vaccine, i.e., one that targets a ubiquitous portion of the influenza virus so that the coverage of a single vaccination can persist for multiple years.

OBJECTIVES

To estimate the economic value of a 'universal' influenza vaccine compared to the standard annual influenza vaccine, starting vaccination in the pediatric population (2-18 year olds), over the course of their lifetime.

PATIENT/METHODS

Monte Carlo decision analytic computer simulation model.

RESULTS

Universal vaccine dominates (i.e., less costly and more effective) the annual vaccine when the universal vaccine cost ≤ $100/dose and efficacy ≥ 75% for both the 5- and 10-year duration. The universal vaccine is also dominant when efficacy is ≥ 50% and protects for 10 years. A $200 universal vaccine was only cost-effective when ≥ 75% efficacious for a 5-year duration when annual compliance was 25% and for a 10-year duration for all annual compliance rates. A universal vaccine is not cost-effective when it cost $200 and when its efficacy is ≤ 50%. The cost-effectiveness of the universal vaccine increases with the duration of protection.

CONCLUSIONS

Although development of a universal vaccine requires surmounting scientific hurdles, our results delineate the circumstances under which such a vaccine would be a cost-effective alternative to the annual influenza vaccine.

Immune aging and autoimmunity

Age is an important risk for autoimmunity, and many autoimmune diseases preferentially occur in the second half of adulthood when immune competence has declined and thymic T cell generation has ceased. Many tolerance checkpoints have to fail for an autoimmune disease to develop, and several of those are susceptible to the immune aging process. Homeostatic T cell proliferation which is mainly responsible for T cell replenishment during adulthood can lead to the selection of T cells with increased affinity to self- or neoantigens and enhanced growth and survival properties. These cells can acquire a memory-like phenotype, in particular under lymphopenic conditions. Accumulation of end-differentiated effector T cells, either specific for self-antigen or for latent viruses, have a low activation threshold due to the expression of signaling and regulatory molecules and generate an inflammatory environment with their ability to be cytotoxic and to produce excessive amounts of cytokines and thereby inducing or amplifying autoimmune responses.

Signal inhibition by the dual-specific phosphatase 4 impairs T cell-dependent B-cell responses with age

T cell-dependent B-cell responses decline with age, suggesting defective CD4 T-cell function. CD4 memory T cells from individuals older than 65 y displayed increased and sustained transcription of the dual-specific phosphatase 4 (DUSP4) that shortened expression of CD40-ligand (CD40L) and inducible T-cell costimulator (ICOS) (both P < 0.001) and decreased production of IL-4, IL-17A, and IL-21 (all P < 0.001) after in vitro activation. In vivo after influenza vaccination, activated CD4 T cells from elderly individuals had increased DUSP4 transcription (P = 0.002), which inversely correlated with the expression of CD40L (r = 0.65, P = 0.002), ICOS (r = 0.57, P = 0.008), and IL-4 (r = 0.66, P = 0.001). In CD4 KO mice reconstituted with DUSP4 OT-II T cells, DUSP4 had a negative effect on the expansion of antigen-specific B cells (P = 0.003) and the production of ova-specific antibodies (P = 0.03) after immunization. Silencing of DUSP4 in memory CD4 T cells improved CD40L (P < 0.001), IL-4 (P = 0.007), and IL-21 (P = 0.04) expression significantly more in the elderly than young adults. Consequently, the ability of CD4 memory T cells to support B-cell differentiation that was impaired in the elderly (P = 0.004) was restored. Our data suggest that increased DUSP4 expression in activated T cells in the elderly in part accounts for defective adaptive immune responses.

Effectiveness of influenza vaccine in aging and older adults: comprehensive analysis of the evidence

Foremost amongst the diseases preventable by vaccination is influenza. Worldwide, influenza virus infection is associated with serious adverse events leading to hospitalization, debilitating complications, and death in elderly individuals. Immunization is considered to be the cornerstone for preventing these adverse health outcomes, and vaccination programs are timed to optimize protection during the annual influenza season. Trivalent inactivated influenza virus vaccines are believed to be both effective and cost-saving; however, in spite of widespread influenza vaccination programs, rates of hospitalization for acute respiratory illness and cardiovascular diseases have been increasing in this population during recent annual influenza seasons. From meta-analyses summarizing estimates of influenza vaccine effectiveness from available observational clinical studies, this review aims to examine how effective current influenza vaccine strategies are in the aging and older adult population and to analyze which are the most important biases that interfere with measurements of influenza vaccine effectiveness. Furthermore, consideration is given to strategies that should be adopted in order to optimize influenza vaccine effectiveness in the face of immune exhaustion.

Public health and economic benefits of new pediatric influenza vaccination programs in Argentina

Background: Argentina’s population was heavily affected by the 2009 influenza pandemic, particularly children, in whom incidence of seasonal influenza is consistently high. Following the pandemic, Argentinean national recommendations for pediatric vaccination against A/H1N1 influenza were defined for all children aged up to five years, in line with programs implemented by national authorities elsewhere. Economic evaluations have found that vaccination programs for this population against seasonal influenza are cost-effective, if not cost-saving in many countries. Recently, Argentina decided to routinely vaccinate against influenza children aged 6–23 mo-old. But, the economic value of such strategies for the country has never been assessed.

 

Methods: A model was developed to assess the value of four different vaccination strategies: (1) no pediatric vaccination; (2) vaccination of 6–23 mo-old children; (3) vaccination of 6–36 mo-old children; (4) vaccination of 6 mo−5 y-old children. We first estimated community health benefits of vaccination then we evaluated the economic and quality-of-life impact of these strategies on the population. Data used in the model come from surveillance networks, published literature, national databases and retrospective hospital-based data.

Results: Pediatric influenza vaccination benefited not only children but also the overall community, due to decreased disease transmission. Our results showed that the recent decision by Argentina to vaccinate 6–23 mo-old children is cost-effective as would be the incremental vaccination of broader age groups.

Conclusions: Results from this study are consistent with previous analyses in other countries confirming that implementing influenza pediatric vaccination programs can be highly cost-effective through individual- and community protection against the disease.

Estimation of the health impact and cost-effectiveness of influenza vaccination with enhanced effectiveness in Canada

Introduction

The propensity for influenza viruses to mutate and recombine makes them both a familiar threat and a prototype emerging infectious disease. Emerging evidence suggests that the use of MF59-adjuvanted vaccines in older adults and young children enhances protection against influenza infection and reduces adverse influenza-attributable outcomes compared to unadjuvanted vaccines. The health and economic impact of such vaccines in the Canadian population are uncertain.

Methods

We constructed an age-structured compartmental model simulating the transmission of influenza in the Canadian population over a ten-year period. We compared projected health outcomes (quality-adjusted life years (QALY) lost), costs, and incremental cost-effectiveness ratios (ICERs) for three strategies: (i) current use of unadjuvanted trivalent influenza vaccine; (ii) use of MF59-adjuvanted influenza vaccine adults ≥65 in the Canadian population, and (iii) adjuvanted vaccine used in both older adults and children aged < 6.

Results

In the base case analysis, use of adjuvanted vaccine in older adults was highly cost-effective (ICER = $2111/QALY gained), but such a program was “dominated” by a program that extended the use of adjuvanted vaccine to include young children (ICER = $1612/QALY). Results were similar whether or not a universal influenza immunization program was used in other age groups; projections were robust in the face of wide-ranging sensitivity analyses.

Interpretation

Based on the best available data, it is projected that replacement of traditional trivalent influenza vaccines with MF59-adjuvanted vaccines would confer substantial benefits to vaccinated and unvaccinated individuals, and would be economically attractive relative to other widely-used preventive interventions.

Cost-effectiveness of influenza vaccination of older adults in the ED setting

OBJECTIVES

Adults older than 50 years are at greater risk for death and severe disability from influenza. Persons in this age group, however, are frequently not vaccinated, despite extensive efforts by physicians to provide this preventive measure in primary care settings. We performed this study to determine if influenza vaccination of older adults in the emergency department (ED) may be cost-effective.

METHODS

Using a probabilistic decision model with quasi-Markov modeling of a typical influenza season, we calculated costs and health outcomes for a hypothetical cohort of patients using parameters from the literature. Three ED-based intervention strategies were compared: (1) no vaccination offered, (2) vaccination offered to patients older than 65 years (limited strategy), and (3) vaccination offered to all patients who are 50 years and older (inclusive strategy). Outcomes were measured as costs, lives saved, and incremental costs per life saved. We performed deterministic and probabilistic sensitivity analyses.

RESULTS

Vaccination of patients 50 years of age and older results in an incremental cost of $34,610 per life saved when compared with the no-vaccination strategy. Limiting vaccination to only those older than 65 years results in an incremental cost of $13,084 per life saved. Results were sensitive to changes in vaccine cost but were insensitive to changes in other model parameters.

CONCLUSIONS

Vaccination of older adults against influenza in the ED setting is cost-effective, especially for those older than 65 years. Emergency departments may be an important setting for providing influenza vaccination to adults who may otherwise have remained unvaccinated.

Importance of employee vaccination against influenza in preventing cases in long-term care facilities

OBJECTIVE

Employees of long-term care facilities (LTCFs) who have contact with residents should be vaccinated against influenza annually to reduce influenza incidence among residents. This investigation estimated the magnitude of the benefit of this recommendation.

METHODS

The New Mexico Department of Health implemented active surveillance in all of its 75 LTCFs during influenza seasons 2006-2007 and 2007-2008. Information about the number of laboratory-confirmed cases of influenza and the proportion vaccinated of both residents and direct-care employees in each facility was collected monthly. LTCFs reporting at least 1 case of influenza (defined alternately by laboratory confirmation or symptoms of influenza-like illness [ILI]) among residents were compared with LTCFs reporting no cases of influenza. Regression modeling was used to obtain adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for the association between employee vaccination coverage and the occurrence of influenza outbreaks. Covariates included vaccination coverage among residents, the staff-to-resident ratio, and the proportion of filled beds.

RESULTS

Seventeen influenza outbreaks were reported during this 2-year period of surveillance. Eleven of these were laboratory confirmed (n = 21 residents) and 6 were defined by ILI (n = 40 residents). Mean influenza vaccination coverage among direct-care employees was 51% in facilities reporting outbreaks and 60% in facilities not reporting outbreaks (P = .12). Increased vaccination coverage among direct-care employees was associated with fewer reported outbreaks of laboratory-confirmed influenza (aOR, 0.97 [95% CI, 0.95-0.99]) and ILI (aOR, 0.98 [95% CI, 0.96-1.00]).

CONCLUSIONS

High vaccination coverage among direct-care employees helps to prevent influenza in LTCFs.

Frailty is associated with impairment of vaccine-induced antibody response and increase in post-vaccination influenza infection in community-dwelling older adults

Annual immunization with a trivalent inactivated vaccine (TIV) is considered efficacious for prevention of seasonal influenza in older adults. However, significant controversy exists in the current literature regarding the clinical effectiveness of TIV immunization in this highly heterogeneous population. Frailty is an important geriatric syndrome characterized by decreased physiologic reserve and increased vulnerability to stressors. Using a validated set of frailty criteria, we conducted a prospective observational study to evaluate TIV-induced strain-specific hemagglutination inhibition (HI) antibody titers and post-vaccination rates of influenza-like illness (ILI) and infection in frail and nonfrail older adults. The results indicate that frailty was associated with significant impairment in TIV-induced strain-specific HI titers and increased rates of ILI and laboratory-confirmed influenza infection. These findings suggest that assessing frailty status in the elderly may identify those who are less likely to respond to TIV immunization and be at higher risk for seasonal influenza and its complications.

Field effectiveness of pandemic and 2009-2010 seasonal vaccines against 2009-2010 A(H1N1) influenza: estimations from surveillance data in France

BACKGROUND

In this study, we assess how effective pandemic and trivalent 2009-2010 seasonal vaccines were in preventing influenza-like illness (ILI) during the 2009 A(H1N1) pandemic in France. We also compare vaccine effectiveness against ILI versus laboratory-confirmed pandemic A(H1N1) influenza, and assess the possible bias caused by using non-specific endpoints and observational data.

METHODOLOGY AND PRINCIPAL FINDINGS

We estimated vaccine effectiveness by using the following formula: VE  =  (PPV-PCV)/(PPV(1-PCV)) × 100%, where PPV is the proportion vaccinated in the population and PCV the proportion of vaccinated influenza cases. People were considered vaccinated three weeks after receiving a dose of vaccine. ILI and pandemic A(H1N1) laboratory-confirmed cases were obtained from two surveillance networks of general practitioners. During the epidemic, 99.7% of influenza isolates were pandemic A(H1N1). Pandemic and seasonal vaccine uptakes in the population were obtained from the National Health Insurance database and by telephonic surveys, respectively. Effectiveness estimates were adjusted by age and week. The presence of residual biases was explored by calculating vaccine effectiveness after the influenza period. The effectiveness of pandemic vaccines in preventing ILI was 52% (95% confidence interval: 30-69) during the pandemic and 33% (4-55) after. It was 86% (56-98) against confirmed influenza. The effectiveness of seasonal vaccines against ILI was 61% (56-66) during the pandemic and 19% (-10-41) after. It was 60% (41-74) against confirmed influenza.

CONCLUSIONS

The effectiveness of pandemic vaccines in preventing confirmed pandemic A(H1N1) influenza on the field was high, consistently with published findings. It was significantly lower against ILI. This is unsurprising since not all ILI cases are caused by influenza. Trivalent 2009-2010 seasonal vaccines had a statistically significant effectiveness in preventing ILI and confirmed pandemic influenza, but were not better in preventing confirmed pandemic influenza than in preventing ILI. This lack of difference might be indicative of selection bias.

Cost-effectiveness of adjuvanted versus nonadjuvanted influenza vaccine in adult hemodialysis patients

BACKGROUND

Currently more than 340,000 individuals are receiving long-term hemodialysis (HD) therapy for end-stage renal disease and therefore are particularly vulnerable to influenza, prone to more severe influenza outcomes, and less likely to achieve seroprotection from standard influenza vaccines. Influenza vaccine adjuvants, chemical or biologic compounds added to a vaccine to boost the elicited immunologic response, may help overcome this problem.

STUDY DESIGN

Economic stochastic decision analytic simulation model.

SETTING & PARTICIPANTS

US adult HD population.

MODEL, PERSPECTIVE, & TIMEFRAME

The model simulated the decision to use either an adjuvanted or nonadjuvanted vaccine, assumed the societal perspective, and represented a single influenza season, or 1 year.

INTERVENTION

Adjuvanted influenza vaccine at different adjuvant costs and efficacies. Sensitivity analyses explored the impact of varying influenza clinical attack rate, influenza hospitalization rate, and influenza-related mortality.

OUTCOMES

Incremental cost-effectiveness ratio of adjuvanted influenza vaccine (vs nonadjuvanted) with effectiveness measured in quality-adjusted life-years.

RESULTS

Adjuvanted influenza vaccine would be cost-effective (incremental cost-effectiveness ratio <$50,000/quality-adjusted life-year) at a $1 adjuvant cost (on top of the standard vaccine cost) when adjuvant efficacy (in overcoming the difference between influenza vaccine response in HD patients and healthy adults) ≥60% and economically dominant (provides both cost savings and health benefits) when the $1 adjuvant's efficacy is 100%. A $2 adjuvant would be cost-effective if adjuvant efficacy was 100%.

LIMITATIONS

All models are simplifications of real life and cannot capture all possible factors and outcomes.

CONCLUSIONS

Adjuvanted influenza vaccine with adjuvant cost ≤$2 could be a cost-effective strategy in a standard influenza season depending on the potency of the adjuvant.