Influenza Vaccination Strategies Research Articles

Seasonal and pandemic influenza: global fatigue versus global preparedness

Seasonal and pandemic influenza: global fatigue versus global preparedness

Vaccination coverage in patients affected by chronic diseases: A 2014 cross-sectional study among subjects hospitalized at Bari Policlinico General Hospital

Subjects affected by at least 1 chronic disease are the target of influenza vaccination strategies because they are at high risk of influenza complications or death. The aim of this cross-sectional study is to evaluate flu and pneumococcal vaccination coverage (VC) in a sample of patients hospitalized at Bari Policlinico General Hospital (South Italy). According to national public health guidelines, these patients should have been vaccinated at hospital discharge by general practitioners. There were 540 patients involved in the study, and the average age was of 46.9 ± 13.4 years (range, 0-64 years). We assessed the vaccination status of 412 of 540 (76.3%) patients. The overall VC was 22.8% (94/412) for influenza and 7.2% (30/412) for pneumococcal vaccine. Doctor recommendation has a pivotal importance in vaccine acceptance, and recent experiences seem to show a high efficacy of the vaccination offer during hospitalization. This model could be helpful to improve influenza and pneumococcal vaccination offers to patient with underlying chronic conditions.

Cost-effectiveness of Strategies for Offering Influenza Vaccine in the Pediatric Emergency Department

ImportanceInfluenza is a significant public health burden, causing morbidity and mortality in children, yet vaccination rates remain low. Vaccination in the pediatric emergency department (PED) setting may be beneficial but, to date, has not been proven to be cost-effective.ObjectiveTo compare the cost-effectiveness of 4 strategies for PED-based influenza vaccine: offering vaccine to all patients, only to patients younger than 5 years, only to high-risk patients (all ages), or to no patients.Design, Setting, and ParticipantsUsing commercial decision analysis software, a cost-effectiveness analysis was performed from January 1, 2016, to June 1, 2017, to compare influenza vaccine strategies at a tertiary, urban, freestanding PED with an estimated 60 000 visits per year among a hypothetical cohort of children visiting the above PED during influenza season. Sensitivity analyses estimated the effect of uncertainties across a variety of input variables (eg, influenza prevalence, vaccine price and effectiveness, and costs of complications).Main Outcomes and MeasuresThe primary outcomes were cost and incremental cost-effectiveness ratio in dollars per influenza case averted. Secondary outcomes included total societal costs, hospitalizations and deaths averted, and quality-adjusted life-years gained.ResultsOffering influenza vaccine to all eligible patients has the lowest cost, at $114.45 (95% CI, $55.48-$245.45) per case of influenza averted. This strategy saves $33.51 (95% CI, $18-$62) per case averted compared with no vaccination, and averages 27 fewer cases of influenza per 1000 patients. Offering vaccine to all patients resulted in 0.72 days (95% CI, 0.18-1.78 days) of quality-adjusted life-years lost, whereas offering to none resulted in 0.91 days (95% CI, 0.25-2.2 days) of quality-adjusted life-years lost. In sensitivity analyses, this strategy remains robustly cost-effective across a wide range of assumptions. In addition to being the most cost-effective strategy regardless of age or risk status, routine vaccination in the PED results in a net societal monetary benefit under many circumstances. In Monte Carlo analysis, offering vaccine to all patients was superior to other strategies in at least 99.8% of cases.Conclusions and RelevanceAlthough few PEDs routinely offer influenza vaccination, doing so appears to be cost-effective, with the potential to significantly reduce the economic (and patient) burden of pediatric influenza.

Efficacy of trivalent influenza vaccine against laboratory-confirmed influenza among young children in a randomized trial in Bangladesh.

Few trials have evaluated influenza vaccine efficacy (VE) in young children, a group particularly vulnerable to influenza complications. We aimed to estimate VE against influenza in children aged <2 years in Bangladesh; a subtropical setting, where influenza circulation can be irregular. Children aged 6-23 months were enrolled 1:1 in a parallel, double-blind, randomized controlled trial of trivalent inactivated influenza vaccine (IIV3) versus inactivated polio vaccine (IPV); conducted August 2010-March 2014 in Dhaka, Bangladesh. Children received two pediatric doses of vaccine, one month apart, and were followed for one year for febrile and respiratory illness. Field assistants conducted weekly home-based, active surveillance and ill children were referred to the study clinic for clinical evaluation and nasopharyngeal wash specimen collection. Analysis included all children who received a first vaccine dose and compared yearly incidence of reverse transcription polymerase chain reaction (RT-PCR)-confirmed influenza between trial arms. The VE was estimated as 1-(rate ratio of illness) × 100%, using unadjusted Poisson regression. The trial was registered with ClinicalTrials.gov, number NCT01319955. Across four vaccination rounds, 4081 children were enrolled and randomized, contributing 2576 child-years of observation to the IIV3 arm and 2593 child-years to the IPV arm. Influenza incidence was 10 episodes/100 child-years in the IIV3 arm and 15 episodes/100 child-years in the IPV arm. Overall, the VE was 31% (95% confidence interval 18, 42%) against any RT-PCR-confirmed influenza. The VE varied by season, but was similar by influenza type/subtype and participant age and sex. Vaccination of young children with IIV3 provided a significant reduction in laboratory-confirmed influenza; however, exploration of additional influenza vaccine strategies, such as adjuvanted vaccines or standard adult vaccine doses, is warranted to find more effective influenza vaccines for young children in low-income countries.

Poor outcomes among elderly patients hospitalized for influenza-like illness

Background and objective: Global Influenza Hospital Surveillance Network is a worldwide initiative that aims to document the burden of influenza infections among acute admissions and vaccine effectiveness in particular countries. As a partner of this platform, we aimed to determine the frequency of influenza infections among acute admissions with influenza-like illness and the outcomes of enrolled patients during the 2015–2016 influenza season in selected hospitals in Turkey.Patients and methods: The investigators screened the hospital admission registries, chart review or available records, and screened all patients hospitalized in the previous 24–48 hours or overnight in the predefined wards or emergency room. A total of 1351 patients were screened for enrollment in five tertiary care referral hospitals in Ankara and 774 patients (57.3% of the initial screened population) were eligible for swabbing. All of the eligible patients who consented were swabbed and tested for influenza with real-time polymerase chain reaction (PCR) based methods.Results: Overall, influenza positivity was detected in 142 patients (18.4%). The predominant influenza strain was A H1N1pdm09. Outcomes were worse among elderly patients, regardless of the presence of the influenza virus. Half of the patients over 65 years of age were admitted to the intensive care unit, while one third required any mode of mechanical ventilation and one fourth died in the hospital in that particular episode.Conclusion: These findings can guide hospitals to plan and prepare for the influenza season. Effective influenza vaccination strategies, particularly aimed at the elderly and adults with chronic diseases, can provide an opportunity for prevention of deaths due to influenza-like illness.

Antibody-dependent phagocytosis (ADP) responses following trivalent inactivated influenza vaccination of younger and older adults

Globally the most commonly utilised immunisation against influenza is the trivalent inactivated influenza vaccine (TIV) derived from an A/H1N1, an A/H3N2 and aB type influenza virus. Vaccine effectiveness of TIV varies year to year, depending on how well antigenically matched the strains in the vaccine are compared to circulating strains [1,2]. Moreover, vaccine effectiveness can vary within certain subpopulations such as HIV-positive, young children and the elderly. Decreased vaccine effectiveness in the elderly is associated with impaired Ab production, as measured by standard hemagglutination inhibition (HAI) assays. We investigated the level of Antibody Dependent Phagocytosis (ADP)-mediating Abs induced by the 2008-TIV in healthy Australian adults aged over and under 60years to determine if this immune function was also reduced in the elderly. We utilised an ADP assay that measures the uptake of IgG-opsonised HA-coated fluorescent microspheres by a monocytic cell line. We also measured HA-specific Abs that are close enough to bind to dimeric FcγRIIa ectodomains in an ELISA-based assay. Furthermore, we compared the extent of cross-reactive recognition of diverse influenza strains by ADP-mediating Abs found in pre- and post-vaccination sera in both of these groups. We found that young adults and older adults mounted similar ADP activity against HAs contained in the 2008-TIV, despite older adults have diminished HI responses. The level of cross-reactive antibodies against other HAs was limited in both groups. We conclude that seasonal influenza vaccination elicits limited cross-reactive ADP to HA in both young and older adults. New influenza vaccination strategies that elicit cross-reactive and polyfunctional antibodies are needed.

Cost-effectiveness and public health impact of alternative influenza vaccination strategies in high-risk adults.

High-dose trivalent inactivated influenza vaccine (HD-IIV3) or recombinant trivalent influenza vaccine (RIV) may increase influenza vaccine effectiveness (VE) in adults with conditions that place them at high risk for influenza complications. This analysis models the public health impact and cost-effectiveness (CE) of these vaccines for 50-64year-olds. Markov model CE analysis compared 5 strategies in 50-64year-olds: no vaccination; only standard-dose IIV3 offered (SD-IIV3 only), only quadrivalent influenza vaccine offered (SD-IIV4 only); high-risk patients receiving HD-IIV3, others receiving SD-IIV3 (HD-IIV3 & SD-IIV3); and high-risk patients receiving HD-IIV3, others receiving SD-IIV4 (HD-IIV3 & SD-IIV4). In a secondary analysis, RIV replaced HD-IIV3. Parameters were obtained from U.S. databases, the medical literature and extrapolations from VE estimates. Effectiveness was measured as 3%/year discounted quality adjusted life year (QALY) losses avoided. The least expensive strategy was SD-IIV3 only, with total costs of $99.84/person. The SD-IIV4 only strategy cost an additional $0.91/person, or $37,700/QALY gained. The HD-IIV3 & SD-IIV4 strategy cost $1.06 more than SD-IIV4 only, or $71,500/QALY gained. No vaccination and HD-IIV3 & SD-IIV3 strategies were dominated. Results were sensitive to influenza incidence, vaccine cost, standard-dose VE in the entire population and high-dose VE in high-risk patients. The CE of RIV for high-risk patients was dependent on as yet unknown parameter values. Based on available data, using high-dose influenza vaccine or RIV in middle-aged, high-risk patients may be an economically favorable vaccination strategy with public health benefits. Clinical trials of these vaccines in this population may be warranted.

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OBJECTIVES/SPECIFIC AIMS: (1) Evaluate safety of a novel influenza vaccination strategy in patients with plasma cell disorders. (2) Measure laboratory-confirmed influenza infection rates following a novel influenza vaccination strategy in patients with plasma cell disorders. (3) Evaluate clinical correlates of response following a novel influenza vaccination strategy in patients with plasma cell disorders. METHODS/STUDY POPULATION: We conducted a double-blind, randomized study over the 2015–16 flu season, comparing 2 doses of Fluzone® High-Dose influenza vaccination (separated by 30 d) to the current standard of care influenza vaccination. Patients were allocated to the experimental arm in 2:1 ratio compared with standard of care arm. Standard of care influenza vaccination was considered single age-based vaccination (standard dose for those &lt;65 y and high dosefor those ≥65 y) and patients in this arm received a saline placebo injection at 30 days to assist in blinding. Eligibility criteria allowed any patient with a PCD and no contraindication to trivalent inactivated influenza vaccine. The primary endpoint was laboratory-confirmed flu infection rate. Protocol-driven surveillance screened patients for flu-like illnesses and performed laboratory testing for influenza until the end of the flu season in May 2016. Secondary endpoints include HAI titer serologic response rates, clinical correlates of protection from influenza infection, and exploratory studies of cell-mediated immunity through characterization of T cell subpopulations, cytokine profiles, and flu-specific T-cell responsiveness. RESULTS/ANTICIPATED RESULTS: In total, 122 plasma cell disorder patients were enrolled (97 with disease requiring therapy and 25 with asymptomatic gammopathy). Of those 48 patients received a single standard of care influenza vaccination and 74 patients received 2 doses of Fluzone® high-dose vaccine. Median age was 67 years (range 42–90). This 2-dose vaccination strategy was safely tolerated in all patients with no grade 2 adverse events attributed to vaccine. With close clinical follow-up, only 4% of patients receiving 2 vaccine doses developed laboratory confirmed influenza Versus 8.3% of those receiving single vaccine. When compared to the expected CDC influenza infection rate of 10%–15%, 1 sample, 2-tailed binomial testing revealed patients receiving 2 vaccines experienced a significantly lower rate of infection than the expected rate (p&lt;0.05) whereas those receiving single vaccine showed no significant difference (p=0.38). DISCUSSION/SIGNIFICANCE OF IMPACT: This randomized study demonstrates that the 2 dose strategy of Fluzone® high-dose influenza vaccine is safely tolerated in patients with plasma cell disorders and associated with significantly less than expected laboratory-confirmed influenza infections. The results suggest that this novel vaccination strategy may have a clinical benefit in reducing influenza infections in plasma cell disorder patients and thus may have practice changing implications. Final analyses of serologic responses, clinical correlates of response, and cell-mediated immune correlates may provide valuable insights into in vivo “immune-competence” in patients with plasma cell disorders.

The anti-influenza M2e antibody response is promoted by XCR1 targeting in pig skin

XCR1 is selectively expressed on a conventional dendritic cell subset, the cDC1 subset, through phylogenetically distant species. The outcome of antigen-targeting to XCR1 may therefore be similar across species, permitting the translation of results from experimental models to human and veterinary applications. Here we evaluated in pigs the immunogenicity of bivalent protein structures made of XCL1 fused to the external portion of the influenza virus M2 proton pump, which is conserved through strains and a candidate for universal influenza vaccines. Pigs represent a relevant target of such universal vaccines as pigs can be infected by swine, human and avian strains. We found that cDC1 were the only cell type labeled by XCR1-targeted mCherry upon intradermal injection in pig skin. XCR1-targeted M2e induced higher IgG responses in seronegative and seropositive pigs as compared to non-targeted M2e. The IgG response was less significantly enhanced by CpG than by XCR1 targeting, and CpG did not further increase the response elicited by XCR1 targeting. Monophosphoryl lipid A with neutral liposomes did not have significant effect. Thus altogether M2e-targeting to XCR1 shows promises for a trans-species universal influenza vaccine strategy, possibly avoiding the use of classical adjuvants.

From Variation of Influenza Viral Proteins to Vaccine Development.

Recurrent influenza epidemics and occasional pandemics are one of the most important global public health concerns and are major causes of human morbidity and mortality. Influenza viruses can evolve through antigen drift and shift to overcome the barriers of human immunity, leading to host adaption and transmission. Mechanisms underlying this viral evolution are gradually being elucidated. Vaccination is an effective method for the prevention of influenza virus infection. However, the emergence of novel viruses, including the 2009 pandemic influenza A (H1N1), the avian influenza A virus (H7N9), and the highly pathogenic avian influenza A virus (HPAI H5N1), that have infected human populations frequently in recent years reveals the tremendous challenges to the current influenza vaccine strategy. A better vaccine that provides protection against a wide spectrum of various influenza viruses and long-lasting immunity is urgently required. Here, we review the evolutionary changes of several important influenza proteins and the influence of these changes on viral antigenicity, host adaption, and viral pathogenicity. Furthermore, we discuss the development of a potent universal influenza vaccine based on this knowledge.

Viral pathogens among elderly people with acute respiratory infections in Shanghai, China: Preliminary results from a laboratory-based surveillance, 2012-2015.

Acute respiratory infections (ARIs), with viral pathogens as the major contributors, are the most common illnesses worldwide, and increase the morbidity and mortality among the elderly population. The clinical and pathological features of elderly people with ARIs need to be identified for disease intervention. From January 1, 2012 through December 31, 2015, respiratory specimens from patients above 60 years old with ARIs were collected from the outpatient and inpatient settings of six sentinel hospitals in Pudong New Area. Each specimen was tested via multiplex polymerase chain reaction (PCR) for eight target viral etiologies including influenza, human rhinovirus (HRV), human para‐influenza virus (PIV), adenovirus (ADV), respiratory syncytial virus (RSV), human metapneumovirus (hMPV), human coronavirus (hCoVs), and human bocavirus (hBoV). A total of 967 elderly patients with ARIs were enrolled, including 589 (60.91%) males, and the median age was 73 years old. 306 (31.64%) patients were tested positive for any one of the eight viruses, including 276 single infections and 30 co‐infections. Influenza was the predominant virus (14.17%, 137/967), detected from 21.35% (76/356) of the outpatients and 9.98% (61/611) of the inpatients. Influenza infections presented two annual seasonal peaks during winter and summer. Compared with non‐influenza patients, those with influenza were more likely to have fever, cough, sore throat, and fatigue. This study identified influenza as the leading viral pathogen among elderly with ARIs, and two seasonal epidemic peaks were observed in Shanghai. An influenza vaccination strategy needs to be advocated for the elderly population.

Canada's pandemic vaccine strategy.

The Public Health Agency of Canada has a mandate to prepare and respond to public health events, including influenza pandemics. Pandemic preparedness requires a multifaceted approach with collaboration from all levels of government. The Canadian Pandemic Influenza Preparedness: Planning Guidance for the Health Sector (CPIP) is a guidance document that outlines key health sector preparedness activities designed to ensure Canada is ready to respond to the next influenza pandemic. This article, the first in a series, outlines Canada's pandemic influenza vaccine strategy as described in the CPIP annex on vaccines. The strategy encompasses all elements of a vaccine program including prioritization of the initial vaccine distribution, securing a pandemic vaccine supply, regulatory approval of a pandemic vaccine, vaccine safety, distribution and storage of the vaccine, allocation and vaccine uptake.

PB1 as a potential target for increasing the breadth of T-cell mediated immunity to Influenza A

Abstract Current influenza vaccines are inducing antibody-mediated immunity toward the surface proteins hemagglutinin and neuraminidase. High variability of these proteins results in costly annual evaluation and production of new vaccines, not providing protection against heterosubtypic or emerging pandemic strains. Consequently, there is a need for a new universal influenza vaccine strategy. Unlike the surface proteins, the internal proteins of influenza are highly conserved. By vaccinating systemically and locally with nucleoprotein encoded in an adenovirus (AdNP) we could induce a protective CD8 T-cell response, that lasted up to at least 8 month post vaccination. To increase the breadth of our vaccine by combining construct, we studied the vaccine potential of another influenza protein. We showed that an adenovirus encoding PB1 elicits high numbers of antigen-specific CD8 T cells in mice. However, in vivo killing of peptide loaded cells was lower in PB1-vaccinated mice than in NP-vaccinated mice. This correlated with a poorer protection against challenge. To explain this, T cells from vaccinated mice were co-incubated with naïve splenocytes loaded with decreasing concentrations of peptide. If T cells were immediately added to the co-cultures, similar dose/response curves regarding IFNγ production was observed. However, if the T cells were added 6 hours after loading, cells from PB1-vaccinated mice required a much higher initial concentration of peptide to be activated compared with NP specific cells, indicating a lower stability of the MHC-PB1peptide complex. These results underscore that not only are T-cell quality and quantity crucial to consider in future vaccine design, but also MHC-peptide interactions.

The Doctrine of Original Antigenic Sin: Separating Good From Evil

The term “original antigenic sin” was coined approximately 60 years ago to describe the imprinting by the initial first influenza A virus infection on the antibody response to subsequent vaccination. These studies did not suggest a reduction in the response to current antigens but instead suggested anamnestic recall of antibody to earlier influenza virus strains. Then, approximately 40 years ago, it was observed that sequential influenza vaccination might lead to reduced vaccine effectiveness (VE). This conclusion was largely dismissed after an experimental study involving sequential administration of then-standard influenza vaccines. Recent observations have provided convincing evidence that reduced VE after sequential influenza vaccination is a real phenomenon. We propose that such reduction in VE be termed “negative antigenic interaction,” given that there is no age cohort effect. In contrast, the potentially positive protective effect of early influenza virus infection later in life continues to be observed. It is essential that we understand better the immunologic factors underlying both original antigenic sin and negative antigenic interaction, to support development of improved influenza vaccines and vaccination strategies.

Lower Rates of Influenza Infection Following Two Dose Series of High Dose Vaccination in Plasma Cell Disorders: Results of a Randomized, Double-Blind, Placebo-Assisted Clinical Trial

Background:Plasma cell disorders (PCDs) are commonly associated with immune paresis and these patients are susceptible to common infections, including influenza, which are a major source of morbidity. Although seasonal influenza vaccination is routinely employed in patients with PCDs, the data about its efficacy is limited. One approach to enhancing the efficacy of influenza vaccination is the use of standard dose boosters, and a prior study with multiple myeloma patients suggested modestly improved seroprotection. Another approach may be increasing the amount of antigen in vaccines. Combining the use of higher antigen dose and a booster strategy, we recently reported a pilot study utilizing a two dose series of high-dose influenza vaccine in patients with plasma cell disorders (Branagan, et al, ASH 2015). Specifically, protective hemagglutination antibody inhibition (HAI) titers rose to 49% after one high-dose influenza vaccine and up to 66% following the second dose. These results compared favorably to historical rates of seroprotection achieved in only 5-19% of PCD patients following standard influenza vaccination. Based on these encouraging results, we designed the present randomized study to further evaluate this novel influenza vaccination strategy in PCD patients.Methods:We conducted a double-blind, randomized clinical trial over the 2015-16 flu season, comparing two doses of Fluzone® High-Dose influenza vaccination (separated by 30 days) to the current standard of care influenza vaccination. Patients were allocated to the experimental arm in 2:1 ratio compared to standard of care arm. Standard of care influenza vaccination was considered single age-based vaccination (standard dose <65 years and high-dose ≥ 65 years) and patients in this arm received a saline placebo injection at 30 days to assist in blinding. Eligibility criteria allowed any patient with a plasma cell disorder and no contraindication to trivalent inactivated influenza vaccine. The primary endpoint was laboratory-confirmed flu infection rate. Patients were asked to report all flu-like illnesses for laboratory testing and patients were asked about infectious symptoms at all study visits and at the end of the flu season in May 2016. Secondary endpoints include HAI titer serologic response rates, clinical correlates of protection from influenza infection, and exploratory studies of cell-mediated immunity through characterization of T cell subpopulations, cytokine profiles, and flu-specific T-cell responsiveness.Results:122 total plasma cell disorder patients were enrolled (97 with disease requiring therapy and 25 with asymptomatic gammopathy). Forty-eight patients received a single standard of care influenza vaccination and 74 patients received two doses of Fluzone® High-Dose vaccine. Median age was 67 years (range 42-90). This two-dose vaccination strategy was safely tolerated in all patients with no ³grade 2 adverse events attributed to vaccine. With close clinical follow-up, only 4% of patients receiving two vaccine doses developed laboratory confirmed influenza versus 8.3% of those receiving single vaccine. When compared to the expected CDC influenza infection rate of 10-15%, one sample, two-tailed binomial testing revealed patients receiving two vaccines experienced a significantly lower rate of infection than the expected rate (p<0.05) whereas those receiving single vaccine showed no significant difference (p=0.38). Analysis of HAI titer results, clinical correlates of protection, and measurements of cell-mediated immunity are underway and will be updated for presentation at ASH 2016.Conclusions:This randomized study demonstrates that the two dose strategy of Fluzone® High-Dose influenza vaccine is safely tolerated in patients with plasma cell disorders and associated with significantly less than expected laboratory-confirmed influenza infections. The results suggest that this novel vaccination strategy may have a clinical benefit in reducing influenza infections in PCD patients and thus may have practice changing implications. Final analyses of serologic responses, clinical correlates of response, and cell-mediated immune correlates may provide valuable insights into in vivo "immune-competence" in PCD. DisclosuresNo relevant conflicts of interest to declare.

Cost-Effectiveness and Public Health Effect of Influenza Vaccine Strategies for U.S. Elderly Adults.

To compare the cost-effectiveness of four influenza vaccines available in the United States for persons aged 65 and older: trivalent inactivated influenza vaccine (IIV3), quadrivalent inactivated influenza vaccine (IIV4), a more-expensive high-dose IIV3, and a newly approved adjuvanted IIV3. Cost-effectiveness analysis using a Markov model and sensitivity analyses. A hypothetical influenza vaccination season modeled according to possible U.S. influenza vaccination policies. Hypothetical cohort of individuals aged 65 and older in the United States. Cost-effectiveness and public health benefits of available influenza vaccination strategies in U.S. elderly adults. IIV3 cost $3,690 per quality-adjusted life year (QALY) gained, IIV4 cost $20,939 more than IIV3 per QALY gained, and high-dose IIV3 cost $31,214 more per QALY than IIV4. The model projected 83,775 fewer influenza cases and 980 fewer deaths with high-dose IIV3 than with the next most-effective vaccine: IIV4. In a probabilistic sensitivity analysis, high-dose IIV3 was the favored strategy if willingness to pay is $25,000 or more per QALY gained. Adjuvanted IIV3 cost-effectiveness depends on its price and effectiveness (neither yet determined in the United States) but could be favored if its relative effectiveness is 15% greater than that of IIV3. From economic and public health standpoints, high-dose IIV3 for adults aged 65 years and older is likely to be favored over the other vaccines, based on currently available data. The cost-effectiveness of adjuvanted IIV3 should be reviewed after its effectiveness has been compared with that of other vaccines and its U.S. price is established.

A broadly neutralizing anti-influenza antibody reveals ongoing capacity of haemagglutinin-specific memory B cells to evolve.

Understanding the natural evolution and structural changes involved in broadly neutralizing antibody (bnAb) development holds great promise for improving the design of prophylactic influenza vaccines. Here we report an haemagglutinin (HA) stem-directed bnAb, 3I14, isolated from human memory B cells, that utilizes a heavy chain encoded by the IGHV3-30 germline gene. MAb 3I14 binds and neutralizes groups 1 and 2 influenza A viruses and protects mice from lethal challenge. Analysis of VH and VL germline back-mutants reveals binding to H3 and H1 but not H5, which supports the critical role of somatic hypermutation in broadening the bnAb response. Moreover, a single VLD94N mutation improves the affinity of 3I14 to H5 by nearly 10-fold. These data provide evidence that memory B cell evolution can expand the HA subtype specificity. Our results further suggest that establishing an optimized memory B cell pool should be an aim of ‘universal' influenza vaccine strategies.

Cost Effectiveness of Influenza Vaccine for U.S. Children: Live Attenuated and Inactivated Influenza Vaccine.

Prior studies showed that live attenuated influenza vaccine (LAIV) is more effective than inactivated influenza vaccine (IIV) in children aged 2-8 years, supporting the Centers for Disease Control and Prevention (CDC) recommendations in 2014 for preferential LAIV use in this age group. However, 2014-2015 U.S. effectiveness data indicated relatively poor effectiveness of both vaccines, leading CDC in 2015 to no longer prefer LAIV. An age-structured model of influenza transmission and vaccination was developed, which incorporated both direct and indirect protection induced by vaccination. Based on this model, the cost effectiveness of influenza vaccination strategies in children aged 2-8 years in the U.S. was estimated. The base case assumed a mixed vaccination strategy where 33.3% and 66.7% of vaccinated children aged 2-8 years receive LAIV and IIV, respectively. Analyses were performed in 2014-2015. Using published meta-analysis vaccine effectiveness data (83% LAIV and 64% IIV), exclusive LAIV use would be a cost-effective strategy when vaccinating children aged 2-8 years, whereas IIV would not be preferred. However, when 2014-2015 U.S. effectiveness data (0% LAIV and 15% IIV) were used, IIV was likely to be preferred. The cost effectiveness of influenza vaccination in children aged 2-8 years is highly dependent on vaccine effectiveness; the vaccine type with higher effectiveness is preferred. In general, exclusive IIV use is preferred over LAIV use, as long as vaccine effectiveness is higher for IIV than for LAIV.

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

BackgroundInfluenza 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.MethodsBased 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.ResultsFree 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.ConclusionsBeijing’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.

Changes of immunogenic profiles between a single dose and one booster influenza vaccination in hemodialysis patients – an 18-week, open-label trial

Annual influenza vaccination is recommended, but its efficacy in dialysis population is still controversial. Here we aimed to compare the dynamic changes of immune response between various influenza vaccination protocols in hemodialysis patients. A 18-week open label, non-randomized, controlled trial was conducted during 2011–2012. The efficacy between unvaccinated, one- and two-dose regimens were evaluated in 175 hemodialysis patients. Immunogenic profiles were assessed by hemagglutination-inhibition assays. At 3–9 weeks post-vaccination, antibody responses were similar between the one- and two-dose regimens, while the seroprotection rates (antibody titer ≥1:40) for influenza A were 55.6–82.5% in the adult (18–60 years) and 33.3–66.7% in the elderly (>60 years). Meanwhile, the seroprotection rates for influenza B were low (4.0–25.0%). By 18 weeks post-vaccination, the seroprotection rates for influenza A and B declined (0.0–33.3%) in both the adult and elderly receiving one- or two-dose regimens. Of dialysis patients, at most 2.4% developed moderate to severe adverse effects(myalgia and headache) after vaccination. In conclusion, the two-dose regimen could not improve immune responses than the one-dose regimen in hemodialysis patients; meanwhile the induced protective antibodies of both regimens could not be maintained for more than 4 months. Modification of current influenza vaccination strategy in dialysis population should be re-considered.