Influenza control in the 21st century: Optimizing protection of older adults

Influenza vaccination in older adults and patients with chronic disorders: A position paper from the Portuguese Society of Pulmonology, the Portuguese Society of Cardiology, the Portuguese Society of Diabetology, the Portuguese Society of Infectious Diseases and Clinical Microbiology, the Portuguese Society of Geriatrics and Gerontology, and the Study Group of Geriatrics of the Portuguese Society of Internal Medicine

Influenza affects millions of people worldwide each year and can lead to severe complications, hospitalizations, and even death, especially among vulnerable populations such as older adults and those with chronic medical conditions. Annual vaccination is considered the most effective measure for preventing influenza and its complications. Despite the widespread availability of influenza vaccines, however, vaccination coverage rates remain suboptimal in several countries. Based on the latest scientific evidence and expert opinions on influenza vaccination in older people and patients with chronic disease, the Portuguese Society of Pulmonology (SPP), the Portuguese Society of Diabetology (SPD), the Portuguese Society of Cardiology (SPC), the Portuguese Society of Geriatrics and Gerontology (SPGG), the Study Group of Geriatrics of the Portuguese Society of Internal Medicine (NEGERMI-SPMI), and the Portuguese Society of Infectious Diseases and Clinical Microbiology (SPDIMC) discussed best practices for promoting vaccination uptake and coverage and drew up several recommendations to mitigate the impact of influenza. These recommendations focus on the efficacy and safety of available vaccines; the impact of influenza vaccination on older adults; patients with chronic medical conditions, namely cardiac and respiratory conditions, diabetes, and immunosuppressive diseases; and health care professionals, optimal vaccination timing, and strategies to increase vaccination uptake and coverage. The resulting position paper highlights the critical role that vaccinations play in promoting public health, raising awareness, and encouraging more people to get vaccinated.

Interseason waning of vaccine-induced hemagglutination inhibition antibody titers and contributing factors to pre-existing humoral immunity against influenza in community-dwelling older adults 75 years and older

BACKGROUND

Seasonal influenza causes significant morbidity and mortality with a disproportionately high disease burden in older adults. Strain-specific hemagglutination-inhibition (HAI) antibody titer is a well-established measure of humoral immunity against influenza and pre-vaccination HAI titer is a valuable indicator of pre-existing humoral immunity at the beginning of each influenza season in highly vaccinated older adults. While vaccine-induced HAI antibody titers are known to wane over time, accurate assessment of their interseason waning has been challenging. This is because pre-vaccination HAI titers are routinely measured using current season vaccine strain antigens instead of the prior season vaccines with which individuals were immunized; as such, they do not accurately represent residual antibody titers from prior season vaccination. This study took advantage of available pre-vaccination HAI titers measured using both current and prior season vaccine strain antigens in a longitudinal influenza immunization study with participants enrolled for multiple consecutive influenza seasons from 2014 through 2017. Influenza A virus (IAV) H3N2 and influenza B virus (IBV) strains in the vaccine formula changed in 2015 and again in 2016 season. IAV H1N1 vaccine strain remained the same from 2014 through 2016 seasons, but changed in 2017. We also investigated factors contributing to pre-existing humoral immunity.

RESULTS

Interseason waning of HAI titers was evident, but rates of waning varied among vaccine strains and study seasons, from 18% (p = .43) to 61% (p < .01). Rates of waning were noticeably greater when pre-vaccination HAI titers were measured by the routine approach, i.e., using current season vaccine strain antigens, from 33% (p = .12) to 83% (p < .01), adjusting for age at prior study season, sex, race, and education. This was largely because the routinely measured pre-vaccination HAI titers underrepresented residual HAI titers from prior season vaccinations. Moreover, interseason antibody waning and prior season post-vaccination HAI titers had significant and independent associations with pre-vaccination HAI titers.

CONCLUSIONS

The routinely measured pre-vaccination HAI titer overestimates interseason HAI antibody waning as it underestimates residual antibody titers from prior season vaccination when virus strains in the vaccine formula change. Moreover, interseason antibody waning and prior season post-vaccination HAI titers independently contribute to pre-existing humoral immunity in this highly vaccinated, community-dwelling older adult population.

Cost-effectiveness of the adjuvanted quadrivalent influenza vaccine in the elderly Belgian population

BACKGROUND

Between 2015 and 2019, when 62% of Belgian adults aged ≥ 65 years were vaccinated with standard quadrivalent influenza vaccines, influenza caused an average of 3,905 hospitalizations and 347 premature deaths per year in older adults. The objective of the present analysis was to estimate the cost-effectiveness of the adjuvanted quadrivalent influenza vaccine (aQIV) compared to the standard (SD-QIV) and high-dose (HD-QIV) vaccines in elderly Belgians.

RESEARCH DESIGN AND METHODS

The analysis was based on a static cost-effectiveness model that captured the evolution of patients infected with influenza and was customized with available national data.

RESULTS

Vaccinating adults aged ≥ 65 years with aQIV instead of SD-QIV would decrease the number of hospitalizations by 530 and the number of deaths by 66 in the 2023-2024 influenza season. aQIV was cost-effective compared to SD-QIV with an incremental cost of €15,227/quality-adjusted life year (QALY). aQIV is cost-saving when compared to HD-QIV in the subgroup of institutionalized elderly adults who were granted reimbursement for this vaccine.

CONCLUSION

In a health care system striving to improve the prevention of infectious diseases, a cost-effective vaccine such as aQIV is a key asset to reduce the number of influenza-related hospitalizations and premature deaths in older adults.

PLAIN LANGUAGE SUMMARY

A flu vaccine containing a unique immune boosting additive reduces medical spending by reducing flu hospitalizations and early deaths in the elderly.

Preliminary evidence that daily light exposure enhances the antibody response to influenza vaccination in patients with dementia

Enhancing lighting conditions in institutions for individuals with dementia improves their sleep, circadian rhythms and well-being. Here, we report first findings that exposure to brighter light during daytime may support the immune response to the annual influenza vaccination. Eighty older institutionalised patients suffering from dementia (54 women and 26 men) continuously wore an activity tracker for 8 weeks to assess individual light exposure and rest-activity cycles. We analysed the patients’ immune response from two blood samples taken before and 4 weeks after the annual influenza vaccination. Individual antibody concentrations to three influenza virus strains (H3N2, H1N1, IB) were quantified via hemagglutination inhibition assays. By quantifying individual light exposure profiles (including daylight), we classified the patients into a low and a high light exposure group based on a median illuminance of 392.6 lux. The two light exposure groups did not differ in cognitive impairment severity, age or gender distribution. However, patients in the high light exposure group showed a significantly greater circadian rest-activity amplitude (i.e., more daytime activity and less nighttime activity) along with a significantly greater antibody titer increase to the H3N2 vaccine than patients in the low light exposure group, despite similar pre-vaccination concentrations. Sufficient seroprotective responses to all three influenza virus strains were attained for ≥75% of participants. These data provide preliminary evidence for a potentially enhanced immune response in patients with dementia when they received more daily light. Future studies are needed to determine whether regular daily light exposure may have beneficial effects on the human immune system, either directly or via a stabilising circadian sleep-wake rhythms.

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Data from individual light exposures and circadian rest-activity cycles in 80 institutionalised patients with dementia.

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Blood samples were taken before and 4 weeks after the annual influenza vaccination.

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Patients with on average higher light exposure had higher specific antibody titer ratios after the influenza strain H3N2 vaccine.

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Circadian rest-activity amplitude and inter-daily stability were also higher in the group with higher daily light exposures.

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The results provide preliminary evidencefor beneficial effects of light on the immune system in patients with dementia.

Immunogenicity and safety of high-dose quadrivalent influenza vaccine in older adults in Taiwan: A phase III, randomized, multi-center study

BACKGROUND

High-dose influenza vaccine offers better protection against influenza/associated complications compared with standard-dose formulation. We evaluated immunogenicity and safety of high-dose influenza vaccine (QIV-HD) and standard-dose (QIV-SD) in older adults (≥ 65 years) in Taiwan.

METHODS

This was a phase III, randomized, modified double-blind, active-controlled, multi-center, descriptive study in older adults. Participants (N = 165) were randomized 1:1 to receive QIV-HD or QIV-SD vaccine (clinicaltrials.gov#NCT04537234).

RESULTS

For all four influenza strains, geometric means titers (GMTs) of hemagglutination inhibition were higher for the QIV-HD than QIV-SD with adjusted GMT ratios (95 % CI) of 2.65 (1.87-3.75) for A/H1N1; 1.76 (1.31-2.38) for A/H3N2; 2.60 (1.90-3.56) for B/Victoria; and 2.01 (1.57-2.56) for B/Yamagata. The seroconversion was higher for QIV-HD than QIV-SD with similar safety profiles across both groups.

CONCLUSION

QIV-HD was highly immunogenic for four influenza strains and have acceptable safety profile in older adults aged ≥ 65 years in Taiwan.

Importance and value of adjuvanted influenza vaccine in the care of older adults from a European perspective - A systematic review of recently published literature on real-world data

BACKGROUND

There is an urgent need for improved influenza vaccines especially for older adults due to the presence of immunosenescence. It is therefore highly relevant to compare enhanced influenza vaccines with traditional influenza vaccines with respect to their effectiveness.

OBJECTIVE

To compare vaccine efficacy and effectiveness of adjuvanted influenza vaccines (aTIV/aQIV) vs. non-adjuvanted standard-dose (TIV/QIV) and high-dose (TIV-HD/QIV-HD) influenza vaccines regarding influenza-related outcomes in older adults, complementing findings from the European Centre for Disease Prevention and Control (ECDC)'s systematic review of enhanced seasonal influenza vaccines from February 2020.

METHODS

A systematic literature search was conducted in Embase and MEDLINE to identify randomised controlled trials, observational studies and systematic reviews, published since ECDC's systematic review (between 7 February 2020 and 6 September 2021). Included studies were appraised with either the Cochrane Risk of Bias tool, ROBINS-I or AMSTAR 2.

RESULTS

Eleven analyses from nine real-world evidence (RWE) studies comprising ∼53 million participants and assessing the relative vaccine effectiveness (rVE) of aTIV vs. TIV, QIV and/or TIV-HD in adults aged ≥65 years over the 2006/07-2008/09 and 2011/12-2019/20 influenza seasons were identified. Nine analyses found that aTIV was significantly more effective than TIV and QIV in reducing influenza-related outcomes by clinical setting and suspected influenza outbreaks (rVE ranging from 7.5% to 25.6% for aTIV vs. TIV and 7.1% to 36.3% for aTIV vs. QIV). Seven analyses found similar effectiveness of aTIV vs. TIV-HD in reducing influenza-related medical encounters, inpatient stays and hospitalisations/emergency room visits. In three analyses, aTIV was significantly more effective than TIV-HD in reducing influenza-related medical encounters and office visits (rVE ranging from 6.6% to 16.6%). Risk of bias of identified studies was moderate to high.

CONCLUSIONS

Our study suggests that both adjuvanted and high-dose vaccines are effective alternatives for vaccination programmes in older adults and preferable over conventional standard-dose vaccines.

A phase 1 dose-sparing, randomized clinical trial of seasonal trivalent inactivated influenza vaccine combined with MAS-1, a novel water-in-oil adjuvant/delivery system

BACKGROUND

New influenza vaccines are needed to increase vaccine efficacy. Adjuvants may allow hemagglutinin (HA) dose-sparing with enhanced immunogenicity. MAS-1 is an investigational low viscosity, free-flowing, water-in-oil emulsion-based adjuvant/delivery system comprised of stable nanoglobular aqueous droplets.

METHODS

A phase 1, double-blind, safety and immunogenicity, HA dose escalation, randomized clinical trial was conducted. MAS-1 adjuvant with 1, 3, 5 or 9 µg per HA derived from licensed seasonal trivalent high dose inactivated influenza vaccine (IIV, Fluzone HD 60 µg per HA) in a 0.3 mL dose were compared to standard dose IIV (Fluzone SD, 15 µg per HA). Safety was measured by reactogenicity, adverse events, and clinical laboratory tests. Serum hemagglutination inhibition (HAI) antibody titers were measured for immunogenicity.

RESULTS

Seventy-two subjects, aged 18-47 years, received one dose of either 0.3 mL adjuvanted vaccine or SD IIV intramuscularly. Common injection site and systemic reactions post-vaccination were mild tenderness, induration, pain, headache, myalgia, malaise and fatigue. All reactions resolved within 14 days post-vaccination. Safety laboratory measures were not different between groups. Geometric mean antibody titers, geometric mean fold increases in antibody titer, seroconversion rates and seroprotection rates against vaccine strains were in general higher and of longer duration (day 85 and 169 visits) with MAS-1-adjuvanted IIV at all doses of HA compared with SD IIV. Adjuvanted vaccine induced higher antibody responses against a limited number of non-study vaccine influenza B and A/H3N2 viruses including ones from subsequent years.

CONCLUSION

MAS-1 adjuvant in a 0.3 mL dose volume provided HA dose-sparing effects without safety concerns and induced higher HAI antibody and seroconversion responses through at least 6 months, demonstrating potential to provide greater vaccine efficacy throughout an influenza season in younger adults. In summary, MAS-1 may provide enhanced, more durable and broader protective immunity compared with non-adjuvanted SD IIV. Clinical Trial Registry: ClinicalTrials.gov # NCT02500680.

MAS-1, a novel water-in-oil adjuvant/delivery system, with reduced seasonal influenza vaccine hemagglutinin dose may enhance potency, durability and cross-reactivity of antibody responses in the elderly

BACKGROUND

Increased influenza vaccine efficacy is needed in the elderly at high-risk for morbidity and mortality due to influenza infection. Adjuvants may allow hemagglutinin (HA) dose-sparing with enhanced immunogenicity. MAS-1 is an investigational water-in-oil emulsion-based adjuvant/delivery system comprised of stable nanoglobular aqueous droplets.

METHODS

A phase 1, randomized, double-blind, safety and immunogenicity, adjuvant dose escalation trial was conducted in persons aged 65 years and older. MAS-1 adjuvant dose volumes at 0.3 mL or 0.5 mL containing 9 µg per HA derived from licensed seasonal trivalent influenza vaccine (IIV, Fluzone HD 60 µg per HA, Sanofi Pasteur) were compared to high dose (HD) IIV (Fluzone HD). Safety was measured by reactogenicity, adverse events, and safety laboratory measures. Immunogenicity was assessed by serum hemagglutination inhibition (HAI) antibody titers.

RESULTS

Forty-five subjects, aged 65-83 years, were randomly assigned to receive 9 µg per HA in 0.3 mL MAS-1 (15 subjects) or HD IIV (15 subjects) followed by groups randomly assigned to receive 9 µg per HA in 0.5 mL MAS-1 (10 subjects) or HD IIV (5 subjects). Injection site tenderness, induration, and pain, and headache, myalgia, malaise and fatigue were common, resolving before day 14 post-vaccination. Clinically significant late-onset injection site reactions occurred in four of ten subjects at the 0.5 mL adjuvant dose. Safety laboratory measures were within acceptable limits. MAS-1-adjuvanted IIV enhanced mean antibody titers, mean-fold increases in antibody titer, and seroconversion rates against vaccine strains for at least 168 days post-vaccination and enhanced cross-reactive antibodies against some non-study vaccine influenza viruses.

CONCLUSION

MAS-1 adjuvant provided HA dose-sparing without safety concerns at the 0.3 mL dose, but the 0.5 mL dose caused late injection site reactions. MAS-1-adjuvanted IIV induced higher HAI antibody responses with prolonged durability including against historical strains, thereby providing greater potential vaccine efficacy in the elderly throughout an influenza season. Clinical Trial Registry: ClinicalTrials.gov # NCT02500680.

Imagining a Personalized Scenario Selectively Increases Perceived Risk of Viral Transmission for Older Adults

The COVID-19 pandemic has created a serious and prolonged public-health emergency. Older adults have been at substantially greater risk of hospitalization, ICU admission, and death due to COVID-19; as of February 2021, over 81% of COVID-19-related deaths in the U.S. occurred for people over the age of 651,2. Converging evidence from around the world suggests that age is the greatest risk factor for severe COVID-19 illness and for the experience of adverse health outcomes3,4. Therefore, effectively communicating health-related risk information requires tailoring interventions to older adults' needs5. Using a novel informational intervention with a nationally-representative sample of 546 U.S. residents, we found that older adults reported increased perceived risk of COVID-19 transmission after imagining a personalized scenario with social consequences. Although older adults tended to forget numerical information over time, the personalized simulations elicited increases in perceived risk that persisted over a 1-3 week delay. Overall, our results bear broad implications for communicating information about health risks to older adults, and they suggest new strategies to combat annual influenza outbreaks.

High-dose influenza vaccination and mortality among predominantly male, white, senior veterans, United States, 2012/13 to 2014/15

Introduction

It is unclear whether high-dose influenza vaccine (HD) is more effective at reducing mortality among seniors.

Aim

This study aimed to evaluate the relative vaccine effectiveness (rVE) of HD.

Methods

We linked electronic medical record databases in the Veterans Health Administration (VHA) and Medicare administrative files to examine the rVE of HD vs standard-dose influenza vaccines (SD) in preventing influenza/pneumonia-associated and cardiorespiratory mortality among VHA-enrolled veterans 65 years or older during the 2012/13, 2013/14 and 2014/15 influenza seasons. A multivariable Cox proportional hazards model was performed on matched recipients of HD vs SD, based on vaccination time, location, age, sex, ethnicity and VHA priority level.

Results

Among 569,552 person-seasons of observation, 207,574 (36%) were HD recipients and 361,978 (64%) were SD recipients, predominantly male (99%) and white (82%). Pooling findings from all three seasons, the adjusted rVE estimate of HD vs SD during the high influenza periods was 42% (95% confidence interval (CI): 24–59) against influenza/pneumonia-associated mortality and 27% (95% CI: 23–32) against cardiorespiratory mortality. Residual confounding was evident in both early and late influenza periods despite matching and multivariable adjustment. Excluding individuals with high 1-year predicted mortality at baseline reduced the residual confounding and yielded rVE of 36% (95% CI: 10–62) and 25% (95% CI: 12–38) against influenza/pneumonia-associated and cardiorespiratory mortality, respectively. These were confirmed by results from two-stage residual inclusion estimations.

Discussion

The HD was associated with a lower risk of influenza/pneumonia-associated and cardiorespiratory death in men during the high influenza period.

Development of vaccines at the time of COVID-19

In December 2019, a working group of the European Academy of Microbiology assembled to discuss various aspects of vaccines and vaccinations. The meeting was organised by Jörg Hacker and Eliora Z. Ron and took place in the offices of the Leopoldina (German National Academy of Sciences Leopoldina). Several important issues were addressed and a major part of the discussion focused on the need to develop new vaccines, especially to protect against pathogens that constitute a pandemic threat. Following the rapid and unpredicted spread of COVID-19 in the first seven months of 2020, the need to develop vaccines for pandemic viruses rapidly has been clearly established. Thus, this paper will concentrate on points that were highlighted by the recent COVID-19 pandemic and lessons learnt therefrom.

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.

Recombinant HA-based vaccine outperforms split and subunit vaccines in elicitation of influenza-specific CD4 T cells and CD4 T cell-dependent antibody responses in humans

Although traditional egg-based inactivated influenza vaccines can protect against infection, there have been significant efforts to develop improved formats to overcome disadvantages of this platform. Here, we have assessed human CD4 T cell responses to a traditional egg-based influenza vaccine with recently available cell-derived vaccines and recombinant baculovirus-derived vaccines. Adults were administered either egg-derived Fluzone^®, mammalian cell-derived Flucelvax^® or recombinant HA (Flublok^®). CD4 T cell responses to each HA protein were assessed by cytokine EliSpot and intracellular staining assays. The specificity and magnitude of antibody responses were quantified by ELISA and HAI assays. By all criteria, Flublok vaccine exhibited superior performance in eliciting both CD4 T cell responses and HA-specific antibody responses, whether measured by mean response magnitude or percent of responders. Although the mechanism(s) underlying this advantage is not yet clear, it is likely that both qualitative and quantitative features of the vaccines impact the response.

Frailty Hinders Recovery From Influenza and Acute Respiratory Illness in Older Adults

BACKGROUND

We examined frailty as a predictor of recovery in older adults hospitalized with influenza and acute respiratory illness.

METHODS

A total of 5011 patients aged ≥65 years were admitted to Canadian Serious Outcomes Surveillance Network hospitals during the 2011/2012, 2012/2013, and 2013/2014 influenza seasons. Frailty was measured using a previously validated frailty index (FI). Poor recovery was defined as death by 30 days postdischarge or an increase of more than 0.06 (≥2 persistent new health deficits) on the FI. Multivariable logistic regression controlled for age, sex, season, influenza diagnosis, and influenza vaccination status.

RESULTS

Mean age was 79.4 (standard deviation = 8.4) years; 53.1% were women. At baseline, 15.0% (n = 750) were nonfrail, 39.3% (n = 1971) were prefrail, 39.8% (n = 1995) were frail, and 5.9% (n = 295) were most frail. Poor recovery was experienced by 21.4%, 52.0% of whom had died. Frailty was associated with lower odds of recovery in all 3 seasons: 2011/2012 (odds ratio [OR] = 0.70; 95% confidence interval [CI], 0.59-0.84), 2012/2013 (OR = 0.72; 95% CI, 0.66-0.79), and 2013/2014 (OR = 0.75; 95% CI, 0.69-0.82); results varied by season, influenza status, vaccination status, and age.

CONCLUSIONS

Increasing frailty is associated with lower odds of recovery, and persistent worsening frailty is an important adverse outcome of acute illness.

Non-ventilator health care-associated pneumonia (NV-HAP): Long-term care

Nonventilator health care-associated pneumonia (NV-HAP) is costly and preventable with significant impact on patient morbidity and mortality. This chapter outlines the increased risk of NV-HAP among individuals residing in long-term care facilities and the incidence of pneumonia in this health care setting which accounts for up to 18% of all persons admitted to acute care hospital for pneumonia. A description of prevention strategies with detail on modifiable and Nonmodifiable risk factors for acquiring pneumonia are presented along with the need for a robust interdisciplinary team and approach for this vulnerable population. In addition, the lack of active surveillance and infection prevention expertise may result in the spread of pathogens that can cause NVHAP outbreaks.

Immune modulatory capacity of probiotic lactic acid bacteria and applications in vaccine development

Vaccination is one of the most important prevention tools providing protection against infectious diseases especially in children below the age of five. According to estimates, more than 5 million lives are saved annually by the implementation of six standard vaccines, including diphtheria, hepatitis B, Haemophilus influenza type b, polio, tetanus and yellow fever. Despite these efforts, we are faced with challenges in developing countries where increasing population and increasing disease burden and difficulties in vaccine coverage and delivery cause significant morbidity and mortality. Additionally, the high cost of these vaccines is also one of the causes for inappropriate and inadequate vaccinations in these regions. Thus, developing cost-effective vaccine strategies that could provide a stronger immune response with reduced vaccination schedules and maximum coverage is of critical importance. In last decade, different approaches have been investigated; among which live bacterial vaccines have been the focus of attention. In this regard, probiotic lactic acid bacteria have been extensively studied as safe and effective vaccine candidates. These microorganisms represent the largest group of probiotic bacteria in the intestine and are generally recognised as safe (GRAS) bacteria. They have also attracted attention due to their immunomodulatory actions and their effective role as novel vaccine adjuvants. A significant property of these bacteria is their ability to mimic natural infections, while intrinsically possessing mucosal adjuvant properties. Additionally, as live bacterial vaccines are administered orally or nasally, they have higher acceptance and better safety, but also avoid the risk of contamination due to needles and syringes. In this review, we emphasise the role of probiotic Lactobacillus strains as putative oral vaccine carriers and novel vaccine adjuvants.

How the Respiratory Epithelium Senses and Reacts to Influenza Virus

The human lung is constantly exposed to the environment and potential pathogens. As the interface between host and environment, the respiratory epithelium has evolved sophisticated sensing mechanisms as part of its defense against pathogens. In this review, we examine how the respiratory epithelium senses and responds to influenza A virus, the biggest cause of respiratory viral deaths worldwide.

Kinetically Deposited Copper Antimicrobial Surfaces

Bacterial and viral contamination of contact surfaces increases the risk of infection. A great deal of work has been done on the capabilities of copper and its alloys to protect against a variety of microorganisms endangering public health, particularly in healthcare and food processing applications. This work has conclusively shown the effectiveness of copper for touch surface disinfection; however, the optimum microstructural characteristics of the copper surface have not been established. The sterilization effectiveness of three kinetically sprayed copper surfaces and two copper feedstocks were examined. The surfaces were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) and influenza A virus. After a two-hour exposure to the surfaces, the surviving microorganisms were assayed, and the results contrasted. These tests showed substantial antimicrobial differences between the coatings generated by the spray techniques and those obtained by different feedstock powders. The significance of the copper spray application was demonstrated, and the application-dependent mechanism for antimicrobial effectiveness was explained.

Analysis of relative effectiveness of high-dose versus standard-dose influenza vaccines using an instrumental variable method

BACKGROUND

Observational studies of the relative effectiveness of influenza vaccines are essential for public health decision making. Their estimates, however, are subject to bias due to unmeasured confounders. Instrumental variable (IV) methods can control for observed and unobserved confounders.

METHODS

We used linked electronic medical record databases in the Veterans Health Administration (VHA) as well as Medicare administrative files to examine the relative vaccine effectiveness (rVE) of high-dose influenza vaccine (HD) versus standard-dose influenza vaccines (SD) in preventing hospitalizations among VHA-enrolled Veterans ≥65 years of age during 5 influenza seasons (2010-2011 through 2014-2015). Using multivariable IV Poisson regression modeling to address unmeasured confounding and bias, we analyzed the data by each season and through longitudinal analysis of all five seasons.

FINDINGS

We included 3,638,924 person-influenza seasons of observation where 158,636 (4%) were among HD vaccine recipients and 3,480,288 (96%) were among SD vaccine recipients. Of the 1,728,562 Veterans, 1,702,824 (98.5%) were male and 1,299,412 (75%) were non-Hispanic white. Based on the longitudinal analysis of all five seasons, the IV-adjusted rVE estimate of HD vs. SD was 10% (95% CI, 8-12%) against all-cause hospitalization; 18% (95% CI, 15-21%) against cardiorespiratory-associated hospitalization; and 14% (95% CI, 6-22%) against influenza/pneumonia-associated hospitalization. The findings by season were similar.

INTERPRETATION

Our analysis of VHA clinical data collected from approximately 1.7 million Veterans 65 years and older during five seasons demonstrates that high-dose influenza vaccine is more effective than standard-dose influenza vaccines in preventing influenza- or pneumonia-associated hospitalizations, cardiorespiratory hospitalizations, and all-cause hospitalizations.

Influenza and the Surgeon

BACKGROUND

The influenza virus is a pathogenic virus responsible for large numbers of deaths and long-term disabilities worldwide. Although the very young, the very old, and immunocompromised individuals are most susceptible, the effects of the influenza virus can be observed across the entire spectrum of individuals.

DISCUSSION

Infection with the influenza virus induces a substantial inflammatory and immunologic response and induces marked pulmonary inflammation. Many aspects of influenza affect surgical patients directly. Vaccines are one of the most effective measures aimed at reducing the prevalence and severity of many infectious diseases, including the influenza virus. Vaccination programs remain one of the highest priorities across the spectrum of countries, research institutions such as the National Institutes of Health, international health agencies such as the World Health Organization (WHO), and major non-profit organizations.

CONCLUSION

This review addresses aspects of the immune and inflammatory response to influenza, with a focus on the elderly population and healthcare providers who may act as reservoirs for virus transmission to the vulnerable surgical population.

Clinical Advances in Viral-Vectored Influenza Vaccines

Influenza-virus-mediated disease can be associated with high levels of morbidity and mortality, particularly in younger children and older adults. Vaccination is the primary intervention used to curb influenza virus infection, and the WHO recommends immunization for at-risk individuals to mitigate disease. Unfortunately, influenza vaccine composition needs to be updated annually due to antigenic shift and drift in the viral immunogen hemagglutinin (HA). There are a number of alternate vaccination strategies in current development which may circumvent the need for annual re-vaccination, including new platform technologies such as viral-vectored vaccines. We discuss the different vectored vaccines that have been or are currently in clinical trials, with a forward-looking focus on immunogens that may be protective against seasonal and pandemic influenza infection, in the context of viral-vectored vaccines. We also discuss future perspectives and limitations in the field that will need to be addressed before new vaccines can significantly impact disease levels.

Cost-effectiveness analysis of different seasonal influenza vaccines in the elderly Italian population

In the perspective of reaching at least 75% influenza vaccination coverage in the elderly and substantial budget constraints, Italian decision makers are facing important challenges in determining an optimal immunization strategy for this growing and particularly vulnerable population. Four different influenza vaccines are currently available for Italian older adults aged 65 years or above, namely trivalent inactivated vaccines (TIVs), MF59-adjuvanted TIV (MF59-TIV), intradermal TIV (ID-TIV) and quadrivalent inactivated vaccines (QIVs). The present study is the first to compare the cost-effectiveness profiles of virtually all possible public health strategies, including the aforementioned four vaccine formulations as well non-vaccination. For this purpose, a decision tree model was built ex novo; the analysis was conducted from the third-payer perspective in the timeframe of one year. All available vaccines were cost-effective compared with non-vaccination. However, MF59-TIV had the most favorable economic profile in the Italian elderly population. Indeed, compared with non-vaccination, it was deemed highly cost-effective with an incremental cost-effectiveness ratio (ICER) of €10,750 per quality-adjusted life year (QALY). The ICER was much lower (€4,527/QALY) when MF59-TIV was directly compared with TIV. ID-TIV and QIV were dominated by MF59-TIV as the former comparators were associated with greater total costs and lower health benefits. Both deterministic and probabilistic sensitivity analyses confirmed robustness of the base case results. From the economic perspective, MF59-TIV should be considered as a preferential choice for Italian older adults aged 65 years or above.

Phase 4, Post-Marketing Safety Surveillance of the MF59-Adjuvanted Influenza Vaccines FLUAD® and VANTAFLU® in South Korean Subjects Aged ≥65 Years

Backgroud

Influenza vaccination is recommended for adults aged ≥65 years as they are at high risk of significant morbidity and mortality. This open-label, multicenter, post-marketing surveillance study assessed the safety of the MF59-adjuvanted trivalent inactivated subunit influenza vaccine, which is marketed as FLUAD^® and VANTAFLU^®, in South Korean subjects aged ≥65 years.

Materials and Methods

Solicited local and systemic adverse events (AEs) were collected from day 1 to 4 of the study. All unsolicited AEs and serious AEs (SAEs) were recorded from day 1 until study termination (day 29).

Results

Of the 770 subjects enrolled (FLUAD^®, n = 389; VANTAFLU^®, n = 381), 39% overall experienced any solicited AE. Local AEs were reported by 33% of subjects overall; with the most common events being injection-site pain (30%) and tenderness (27%). Systemic AEs were reported by 19% of subjects overall with the most common events being myalgia (11%) and fatigue (8%).

Conclusion

These results show that the MF59-adjuvanted influenza vaccine known as FLUAD^® or VANTAFLU^® had acceptable safety profiles in older adults (aged ≥65 years) in South Korea.

Aging, cytomegalovirus (CMV) and influenza vaccine responses

Influenza vaccination is less effective in elderly as compared to young individuals. Several studies have identified immune biomarkers able to predict a protective humoral immune response to the vaccine. In this review, we summarize current knowledge on the effects of aging on influenza vaccine responses and on biomarkers so far identified, and we discuss the relevance of latent cytomegalovirus (CMV) infection on these vaccine responses.

Waning protection of influenza vaccination during four influenza seasons, 2011/2012 to 2014/2015

BACKGROUND

Concerns have been raised about intraseasonal waning of the protection conferred by influenza vaccination.

METHODS

During four influenza seasons, we consecutively recruited individuals aged 18years or older who had received seasonal influenza vaccine and were subsequently admitted to the hospital for influenza infection, asassessed by reverse transcription polymerase chain reaction. We estimated the adjusted odds ratio (aOR) of influenza infection by date of vaccination, defined by tertiles, as early, intermediate or late vaccination. We used a test-negative approach with early vaccination as reference to estimate the aOR of hospital admission with influenza among late vaccinees. We conducted sensitivity analyses by means of conditional logistic regression, Cox proportional hazards regression, and using days between vaccination and hospital admission rather than vaccination date.

RESULTS

Among 3615 admitted vaccinees, 822 (23%) were positive for influenza. We observed a lower risk of influenza among late vaccinees during the 2011/2012 and 2014/2015A(H3N2)-dominant seasons: aOR=0.68 (95% CI: 0.47-1.00) and 0.69 (95% CI: 0.50-0.95). We found no differences in the risk of admission with influenza among late versus early vaccinees in the 2012/2013A(H1N1)pdm09-dominant or 2013/2014B/Yamagata lineage-dominant seasons: aOR=1.18 (95% CI: 0.58-2.41) and 0.98 (95% CI: 0.56-1.72). When we restricted our analysis to individuals aged 65years or older, we found a statistically significant lower risk of admission with influenza among late vaccinees during the 2011/2012 and 2014/2015A(H3N2)-dominant seasons: aOR=0.61 (95% CI: 0.41-0.91) and 0.69 (95% CI: 0.49-0.96). We observed 39% (95% CI: 9-59%) and 31% (95% CI: 5-50%) waning of vaccine effectiveness among participants aged 65years or older during the two A(H3N2)-dominant seasons. Similar results were obtained in the sensitivity analyses.

CONCLUSION

Waning of vaccine protection was observed among individuals aged 65years old or over in two A(H3N2)-dominant influenza seasons.

Impact of Aging and Cytomegalovirus on Immunological Response to Influenza Vaccination and Infection

The number of people over the age of 60 is expected to double by 2050 according to the WHO. This emphasizes the need to ensure optimized resilience to health stressors in late life. In older adults, influenza is one of the leading causes of catastrophic disability (defined as the loss of independence in daily living and self-care activities). Influenza vaccination is generally perceived to be less protective in older adults, with some studies suggesting that the humoral immune response to the vaccine is further impaired in cytomegalovirus (CMV)-seropositive older people. CMV is a β-herpes virus infection that is generally asymptomatic in healthy individuals. The majority of older adults possess serum antibodies against the virus indicating latent infection. Age-related changes in T-cell-mediated immunity are augmented by CMV infection and may be associated with more serious complications of influenza infection. This review focuses on the impact of aging and CMV on immune cell function, the response to influenza infection and vaccination, and how the current understanding of aging and CMV can be used to design a more effective influenza vaccine for older adults. It is anticipated that efforts in this field will address the public health need for improved protection against influenza in older adults, particularly with regard to the serious complications leading to loss of independence.

A trivalent, inactivated influenza vaccine (Vaxigrip®): summary of almost 50 years of experience and more than 1.8 billion doses distributed in over 120 countries

INTRODUCTION

Vaxigrip, a trivalent split-virion, inactivated vaccine available since 1968 has been in use longer than any other influenza vaccine. It is the most widely-used influenza vaccine, with more than 1.8 billion doses distributed in more than 120 countries. Areas covered: The significant body of evidence that confirms the efficacy, effectiveness, immunogenicity, and safety of Vaxigrip in healthy individuals of all ages and at-risk populations is summarized. The results from at least 15 randomized efficacy trials and 15 other studies have demonstrated that vaccination with Vaxigrip is efficacious against various clinical endpoints. It was estimated that more than 37 million laboratory-confirmed influenza episodes, 476,000 influenza-related hospitalizations, and 67,000 influenza-related deaths have been avoided by the more than 1.8 billion doses of Vaxigrip that have been distributed, emphasizing its important public health impact. Expert commentary: This strong evidence base in favor of Vaxigrip provides a robust foundation to support the implementation of the quadrivalent formulation. This quadrivalent formulation of Vaxigrip contains two A and two B influenza strains (VaxigripTetra), and has a similar immunogenicity and safety profile to the trivalent formulation while offering broader protection due to the addition of the second influenza B strain.

Autophagy and Immune Senescence

With extension of the average lifespan, aging has become a heavy burden in society. Immune senescence is a key risk factor for many age-related diseases such as cancer and increased infections in the elderly, and hence has elicited much attention in recent years. As our body's guardian, the immune system maintains systemic health through removal of pathogens and damage. Autophagy is an important cellular 'clearance' process by which a cell internally delivers damaged organelles and macromolecules to lysosomes for degradation. Here, we discuss the most current knowledge of how impaired autophagy can lead to cellular and immune senescence. We also provide an overview, with examples, of the clinical potential of exploiting autophagy to delay immune senescence and/or rejuvenate immunity to treat various age-related diseases.

Recommended immunization schedules for adults: Clinical practice guidelines by the Escmid Vaccine Study Group (EVASG), European Geriatric Medicine Society (EUGMS) and the World Association for Infectious Diseases and Immunological Disorders (WAidid)

Rapid population aging has become a major challenge in the industrialized world and progressive aging is a key reason for making improvement in vaccination a cornerstone of public health strategy. An increase in age-related disorders and conditions is likely to be seen in the near future, and these are risk factors for the occurrence of a number of vaccine-preventable diseases. An improvement in infectious diseases prevention specifically aimed at adults and the elderly can therefore also decrease the burden of these chronic conditions by reducing morbidity, disability, hospital admissions, health costs, mortality rates and, perhaps most importantly, by improving the quality of life. Among adults, it is necessary to identify groups at increased risk of vaccine-preventable diseases and highlight the epidemiological impact and benefits of vaccinations using an evidence-based approach. This document provides clinical practice guidance on immunization for adults in order to provide recommendations for decision makers and healthcare workers in Europe. Although immunization is considered one of the most impactful and cost-effective public health measures that can be undertaken, vaccination coverage rates among adults are largely lower than the stated goal of ≥ 95% among adults, and stronger efforts are needed to increase coverage in this population. Active surveillance of adult vaccine-preventable diseases, determining the effectiveness of the vaccines approved for marketing in the last 5 y, the efficacy and safety of vaccines in immunocompromised patients, as well as in pregnant women, represent the priorities for future research.

Immunogenicity and Safety of Intradermal Influenza Vaccine in the Elderly: A Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

Immunosenescence makes the elderly more susceptible to influenza complications and less responsive to vaccination. An intradermal formulation (IDflu) is one of several strategies being investigated to increase the immunogenicity of influenza vaccines.

OBJECTIVE

The overall goal of the study was to assess the safety and immunogenicity of IDflu compared with the intramuscular route (IMflu) in the elderly.

METHODS

A meta-analysis of randomized controlled trials (RCTs) was performed. Included articles met the following criteria: RCTs; primary studies, not re-analyses or reviews; enrolment of elderly people; comparing the immunogenicity and/or safety of IDflu with IMflu; measuring seroprotection and/or seroconversion rate to assess immunogenicity; measuring local reactions and/or general symptoms and/or other mild local reactions that could affect acceptability of vaccine as safety indicators, according to the European Medicines Agency (EMA) criteria; published through January 2015.

RESULTS

The results of our meta-analysis on seroprotection showed that IDflu is comparable to IMflu for each strain (A/H1N1: risk ratio [RR] 1.02, 95% confidence interval [CI] 0.98-1.07; A/H3N2: RR 1.01, 95% CI 0.99-1.04; B 1.02, 95% CI 0.98-1.08). The seroconversion rate achieved with IDflu was comparable to that of the control group (A/H1N1: RR 1.08, 95% CI 0.97-1.2; A/H3N2: RR 1.08, 95% CI 0.96-1.21; B: RR 1.21, 95% CI 1-1.45). Systemic reactogenicity appeared similar in the two groups, while local reactions were significantly more frequent in the IDflu group.

CONCLUSIONS

The novel IDflu appears to have the adequate balance between immunogenicity and safety in the elderly compared with IMflu, and its utilization may be considered among the possible strategies to enhance the control of seasonal influenza outbreaks according to the existing policy recommendations in the elderly.

Neighborhood Influences on Seasonal Influenza Vaccination among Older African Americans in Atlanta, Georgia

BACKGROUND

Influenza vaccination coverage in the US is lower than the recommended Healthy People 2020 threshold, especially among older African Americans. This analysis explores the complex relationship among neighborhood-level factors, socio behavioral influences, and influenza vaccination outcomes among older African Americans.

METHODS

We analyzed data from 221 Black/African American participants' age ≥50 years living in Atlanta, Georgia. Generalized Estimating Equations for linear and logistic models assessed associations among socio demographic factors, census-tract neighborhood characteristics, and reported 2012-2013 seasonal influenza vaccination receipt, controlling for correlations among individuals within the same census tracts. Evaluated environmental factors included neighborhood deprivation indicators such as vacant housing percentage, vehicle availability, area violent crimes, and racial/ethnic composition.

RESULTS

Reported greater influenza immunization uptake was significantly associated with older age ≥65 years [OR=1.05, p=0.04], positive vaccination attitudes [OR=5.30, p<0.01], having health insurance [OR=14.37, p=0.03], lower perceived neighborhood security [OR=0.51, p=0.02], and lower neighborhood vehicle ownership [OR=1.07, p=0.04], a proxy for neighborhood affluence and transportation ease. Having a post-secondary education was significantly associated with both positive perceived neighborhood security [β=0.28, p=0.02] and positive vaccination attitudes [β=0.27, p=0.02].

CONCLUSION

The findings provide evidence for distal neighborhood-level influences on influenza vaccination uptake among older African Americans. Lower vehicle ownership and lower perceived neighborhood security influenced seasonal influenza immunizations. Those who perceived personal risk, based on reported neighborhood security, displayed intent to obtain the seasonal influenza vaccine. Further investigation of multilevel, socio geographic factors is therefore warranted to more effectively address suboptimal influenza vaccine coverage among this population.

Who benefits most from influenza vaccination policy: a study among the elderly in Beijing, China

Background

Influenza continues to have a major impact on vulnerable populations worldwide, particularly among the elderly (≥60 years of age). Vaccination for targeted groups is recommended by the WHO as the most effective way to control influenza infections. Since 2009, the Beijing municipal government has provided influenza vaccination to the elderly at no out-of-pocket cost to reduce influenza threats and improve related health equality. The study aims to evaluate the equality of the policy, and to analyze factors that bring influences to equality.

Methods

Based on data from a household survey, concentration index (CI) was calculated to measure the socioeconomic inequality in influenza vaccination. A Logit regression model was used to decompose CI, in which the contribution of each determinant was calculated and the percentages of these contribution were obtained.

Results

Free influenza vaccination at point of use shows significant pro-poor distribution among the elderly in Beijing (CI = −0.115). After the decomposition of CI, the elderly with lower income, higher education, and living in rural areas were more likely to get the influenza vaccination, in which place of residence (contribution percentage = 57 %) held the most contribution of variance.

Conclusions

Beijing’s free influenza vaccination strategy at point of use could provide the poor elderly with equal opportunities to receive preventive health service, showing a significant pro-poor distribution. The poor elderly, who live in rural areas with high education, benefit most from the policy. Further policy interventions should target the population living in urban areas in order to improve the utilization of public health services and health equality.

Modeling Influenza Virus Infection: A Roadmap for Influenza Research

Influenza A virus (IAV) infection represents a global threat causing seasonal outbreaks and pandemics. Additionally, secondary bacterial infections, caused mainly by Streptococcus pneumoniae, are one of the main complications and responsible for the enhanced morbidity and mortality associated with IAV infections. In spite of the significant advances in our knowledge of IAV infections, holistic comprehension of the interplay between IAV and the host immune response (IR) remains largely fragmented. During the last decade, mathematical modeling has been instrumental to explain and quantify IAV dynamics. In this paper, we review not only the state of the art of mathematical models of IAV infection but also the methodologies exploited for parameter estimation. We focus on the adaptive IR control of IAV infection and the possible mechanisms that could promote a secondary bacterial coinfection. To exemplify IAV dynamics and identifiability issues, a mathematical model to explain the interactions between adaptive IR and IAV infection is considered. Furthermore, in this paper we propose a roadmap for future influenza research. The development of a mathematical modeling framework with a secondary bacterial coinfection, immunosenescence, host genetic factors and responsiveness to vaccination will be pivotal to advance IAV infection understanding and treatment optimization.

A Novel Dynamic Model for Health Economic Analysis of Influenza Vaccination in the Elderly

Introduction

New vaccines are being developed to improve the efficacy of seasonal influenza immunization in elderly persons aged ≥65 years. These products require clinical and economic evaluation to aid policy decisions.

Methods

To address this need, a two-part model has been developed, which we have applied to examine the potential clinical and economic impact of vaccinating elderly persons with adjuvanted trivalent inactivated influenza vaccine (aTIV) relative to conventional trivalent (TIV) and quadrivalent (QIV) vaccines. We compared outcomes in the US population for (1) aTIV in persons aged ≥65 years and QIV in all other age cohorts; (2) QIV in all cohorts; (3) TIV in all cohorts. Low, average, and high intensity seasons with low, average, and high vaccine match scenarios were compared. Probabilistic sensitivity analysis was conducted within each discrete scenario to explore the impact of variation in model inputs on potential outcomes.

Results

Assuming current vaccination coverage rates in the US population with (a) 25% better efficacy of adjuvanted versus non-adjuvanted vaccine against any strain and (b) 35% better efficacy of non-adjuvanted vaccine against matched B versus mismatched B strains, use of aTIV in persons aged ≥65 years and QIV in persons <65 years could reduce influenza cases by 11,166–1,329,200, hospitalizations by 1365–43,674, and deaths by 421–11,320 versus use of QIV in all cohorts. These outcomes are reflected in a corresponding increase in quality-adjusted life-years (QALYs) of 3003–94,084. If the prevalence of mismatched influenza B was >54.5% of all circulating strains, use of QIV in all cohorts would offset the clinical benefits of aTIV. Elderly aTIV or QIV vaccination was associated with improved outcomes over non-adjuvanted TIV in many of the scenarios, particularly in low match seasons of any intensity. Total cost savings (including direct and indirect healthcare costs plus productivity impacts) with aTIV in the elderly versus QIV in the whole population ranged from $27 million (low intensity, low match) to $934 million (high intensity, high match). Univariate sensitivity analysis of relative vaccine prices in the average intensity, average match scenario indicated that aTIV could be marginally cost saving relative to QIV at the currently published Medicare price for influenza vaccines offering enhanced efficacy in the elderly. Elderly vaccination with aTIV was associated with a higher overall cost compared with TIV in only two scenarios (low intensity with average or high match); the incremental cost/QALY relative to TIV was $9980 in the average match scenario and $28,800 in the high match scenario.

Conclusions

Vaccination of persons aged ≥65 years with aTIV has the potential to provide clinical and economic benefit relative to QIV and TIV. The new model allows the assessment of various alternative strategies for available influenza vaccines.

Funding

Novartis Vaccines.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-015-0076-8) contains supplementary material, which is available to authorized users.

Estimating the Effect of Influenza Vaccination on Nursing Home Residents' Morbidity and Mortality

OBJECTIVES

To estimate the effect of influenza vaccination on hospitalization and mortality in nursing home (NH) residents.

DESIGN

Retrospective cohort study.

SETTING

Medicare claims data linked to NH Minimum Data Set assessments and Centers for Disease Control and Prevention (CDC) surveillance data from 122 U.S. cities.

PARTICIPANTS

More than 1 million Medicare fee-for-service, long-stay NH residents between 2000 and 2009.

MEASUREMENTS

Weekly facility outcome aggregates of NH resident pneumonia and influenza (P&I) hospitalizations and all-cause mortality and city-level P&I mortality as reported by the CDC were created. The seasonal vaccine match rate for influenza A/H1N1, A/H3N2, and B strains was calculated, and each outcome was compared in seasons of high and low match rates using facility fixed-effects regression models separately for full-year and nonsummer months.

RESULTS

Average weekly all-cause mortality varied across seasons from 3.74 to 4.13 per 1,000 NH residents per week, and hospitalization for P&I varied from 2.05 to 2.43. Vaccine match rates were invariably high for H1N1 but variable across seasons for the other two types. The association between vaccine match and reduction in overall mortality and P&I hospitalizations was strongest for A/H3N2, the influenza strain typically responsible for the most-severe influenza cases. Given the approximately 130,000 deaths and 77,000 P&I hospitalizations of long-stay NH residents during the 32 nonsummer weeks, the model estimated that a 50-percentage-point increase in the A/H3N2 match rate (from <25% to >75%) reduced long-stay NH resident deaths by 2.0% and P&I hospitalizations by 4.2%.

CONCLUSION

Well-matched influenza vaccine prevents P&I hospitalizations and mortality in NH residents.

Live attenuated influenza vaccine tetravalent: a clinical review

Live attenuated influenza vaccine (LAIV) has been available as a trivalent formulation in the EU since 2012. Influenza B strains from two lineages have co-circulated outside Asia in Europe, Israel and North America since the early 2000s. The trivalent vaccine contained a single influenza B lineage virus chosen primarily on the basis of the previous year's circulating lineage. Failure to align the vaccine virus with the circulating virus leaves even vaccinated patients, particularly children, at risk for infection with B viruses from the other lineage. Recently, a tetravalent formulation was approved and use will begin during the 2014-2015 influenza season. Approval of LAIV Tetra was based on the established efficacy and safety of trivalent LAIV and studies demonstrating similar immunogenicity between the trivalent and tetravalent vaccines. Addition of a fourth strain to the vaccine will address the issue of co-circulation of influenza B viruses and provide a broader range of protection.

Maximising influenza vaccination uptake among older people

Older adults aged 65 years and over are particularly vulnerable to seasonal influenza as their immune system is weaker than that of younger adults. The influenza vaccination helps to reduce influenza severity and the incidence of complications, but a range of factors can affect uptake among older people. These factors can be categorised as follows: the system of vaccination; influenza vaccination mistrust and fear of side-effects; health beliefs and behaviours; and other factors. Various interventions to maximise influenza vaccination uptake among older people in the community have been identified, including: interventions to increase community demand, enhance access and improve influenza vaccination among community nurses, as well as provider or system-based interventions and societal interventions. Community nurses have been found to have a positive influence on influenza vaccination uptake and should continue to promote the benefits of influenza vaccination to their patients who are 'persistent decliners'.

B cell function and influenza vaccine responses in healthy aging and disease

Influenza vaccination is less effective in elderly as compared to young individuals. Several studies have addressed the identification of immune biomarkers able to monitor or predict a protective humoral immune response to the vaccine. In this review, we summarize these data, with emphasis on the effects of aging on influenza vaccine-specific B cell responses in healthy individuals and patients with Type-2 Diabetes, HIV and cardiovascular diseases.

Vaccine responsiveness in the elderly: best practice for the clinic

The success of vaccines developed since the beginning of the 20th century, has enabled the conquest of several childhood diseases preventing death and or disability for millions of children. But, globally, the number of children will soon be surpassed by the number of adults over the age of 65. The active lifestyle of these older individuals, coupled with a degree of immune deficiency recognised within this population will lead to a change in the profile of diseases affecting the elderly. The challenge for policy makers and also those involved in primary healthcare is how to protect this population from communicable diseases and keep them healthy, autonomous and independent when vaccines in the main have been developed for use on children and young adults.

2012-2013 Seasonal influenza vaccine effectiveness against influenza hospitalizations: results from the global influenza hospital surveillance network

Background

The effectiveness of currently licensed vaccines against influenza has not been clearly established, especially among individuals at increased risk for complications from influenza. We used a test-negative approach to estimate influenza vaccine effectiveness (IVE) against hospitalization with laboratory-confirmed influenza based on data collected from the Global Influenza Hospital Surveillance Network (GIHSN).

Methods and Findings

This was a multi-center, prospective, active surveillance, hospital-based epidemiological study during the 2012–2013 influenza season. Data were collected from hospitals participating in the GIHSN, including five in Spain, five in France, and four in the Russian Federation. Influenza was confirmed by reverse transcription-polymerase chain reaction. IVE against hospitalization for laboratory-confirmed influenza was estimated for adult patients targeted for vaccination and who were swabbed within 7 days of symptom onset. The overall adjusted IVE was 33% (95% confidence interval [CI], 11% to 49%). Point estimates of IVE were 23% (95% CI, −26% to 53%) for influenza A(H1N1)pdm09, 30% (95% CI, −37% to 64%) for influenza A(H3N2), and 43% (95% CI, 17% to 60%) for influenza B/Yamagata. IVE estimates were similar in subjects <65 and ≥65 years of age (35% [95% CI, −15% to 63%] vs.31% [95% CI, 4% to 51%]). Heterogeneity in site-specific IVE estimates was high (I² = 63.4%) for A(H1N1)pdm09 in patients ≥65 years of age. IVE estimates for influenza B/Yamagata were homogenous (I² = 0.0%).

Conclusions

These results, which were based on data collected from the GIHSN during the 2012–2013 influenza season, showed that influenza vaccines provided low to moderate protection against hospital admission with laboratory-confirmed influenza in adults targeted for influenza vaccination. In this population, IVE estimates against A(H1N1)pdm09 were sensitive to age group and study site. Influenza vaccination was moderately effective in preventing admissions with influenza B/Yamagata for all sites and age groups.

Vaccine-preventable diseases: from paediatric to adult targets

The morbidity and mortality related to many communicable infectious diseases have significantly decreased in Western countries largely because of the use of antibiotics, and the implementation of well-planned vaccination strategies and national immunisation schedules specifically aimed at infants and children. However, although immunisation has proved to be highly effective for public health, more effort is needed to improve the currently sub-optimal rates of vaccination against various diseases among adults who may be at risk because of their age, medical condition or occupation. The vaccines currently licenced in Western countries are safe, immunogenic and effective against many infectious diseases and their complications, but the availability of newer vaccines or vaccines with new indications, the evolving ecology and epidemiology of many infections, population ageing, and other demographic changes (i.e. the increasing prevalence of chronic comorbidities and immunodeficiencies, mass migration, new working relationships, and widespread international tourism) require changes in the approach to immunisation. There is now a need for appropriate preventive measures for adults and the elderly aimed at protecting people at risk by using every possible catch-up opportunity and recommending specific age-related schedules on the basis of local epidemiology.

High TNF-α levels in resting B cells negatively correlate with their response

Aging significantly decreases the influenza vaccine-specific response as we and others have previously shown. Based on our previous data in aged mice, we hypothesize that the inflammatory status of the individual and of B cells themselves would impact B cell function. We here show that the ability to generate a vaccine-specific antibody response is negatively correlated with levels of serum TNF-α. Moreover, human unstimulated B cells from elderly make higher levels of TNF-α than those from young individuals, and these positively correlate with serum TNF-α levels. These all negatively correlate with B cell function, measured by activation-induced cytidine deaminase, the enzyme of class switch recombination and somatic hypermutation. Only memory B cells (either IgM or switched), but not naïve B cells, make appreciable levels of TNF-α and more in elderly as compared to young individuals. Finally, an anti-TNF-α antibody can increase the response in cultured B cells from the elderly, suggesting that TNF-α secreted by memory B cells affects IgM memory B cells and naïve B cells in an autocrine and/or paracrine manner. Our results show an additional mechanism for reduced B cell function in the elderly and propose B cell-derived TNF-α as another predictive biomarker of in vivo and in vitro B cell responses.

Dose response kinetics of CD8 lymphocytes from young animals transfused into old animals and challenged with influenza

Transfusion of autologous leukocytes after prolonged storage has been proposed as a means of rejuvenating the immune system of older individuals. The rationale for this approach is that age related immune decline is associated with a diminished pool of naïve T cells following atrophy of the thymus and reduction in thymic output. The presence of high levels of naïve T cells within the blood of young individuals could provide a boost to the immune system of an older “self” through a rejuvenation of the naïve T cell pool. However what remains unresolved is whether the cells could be incorporated effectively into the T cell pool of the host and whether effectors could be generated. Using CD45 congenic mice in our experiments we show that the transfusion of young donor cells into older congenic host animals leads to their successful incorporation into the peripheral T cell pool. When the recipients were challenged with influenza virus, specific effector CD8 cells were generated which were of both host and donor origin. We found no relationship between the number of responder cells of donor origin at the time of assay and the number of cells injected.