Prevent Influenza Infection Research Articles

Are social inequalities in influenza vaccination coverage in Japan reduced by health policy?

Influenza vaccination is effective to prevent influenza infection. However, findings about association between socioeconomic status and influenza vaccination coverage are controversial. Online survey was conducted among 4995 participants between 20 and 69 years of age throughout Japan, January 2017. We asked about history of receiving vaccination in previous year and socioeconomic status, with their reasons for having vaccination or not. Age stratified multivariable logistic regression model was conducted to estimate the odds ratio (ORs) and 95% confidence intervals (CIs) of receiving vaccine for each educational level and income. Sex, self-reported health status, marital status and income were included as covariates. The rate for receiving influenza vaccine among ≤64 year-olds and ≥65 year-olds was 32.9% and 35.4%, respectively. Among younger adults, vaccination varied by each education: junior high school, 23.6%; senior high school, 27.2%; college, 32.6%; university, 36.2%; and graduate school, 39.8%. Compared to junior high school, those from graduate school tended to be more vaccinated (OR1.88, 95%CI 1.07–3.24). On the contrary, those aged above ≥65 years old received vaccination with no significant differences across education. Likewise, among respondents aged ≤64 year-olds, income was significantly associated with influenza vaccination. Despite being “Managed by school or company” (32.5%), having “No particular reason” was the frequent reason for both receiving influenza vaccination (23.8%) or not (34.3%). Adults with higher educational level were significantly more likely to receive vaccination. Subsidizing influenza vaccination may reduce inequality in receiving vaccination for adults. Strengthening vaccination through various approaches is necessary, such as managing by school or company.

Evaluating the effectiveness of the influenza vaccine during respiratory outbreaks in Singapore’s long term care facilities, 2017

Influenza outbreaks occur periodically in Long Term Care Facilities (LTCFs) and vaccination is critical in preventing influenza infections. We evaluated the influenza vaccine effectiveness (VE) during respiratory outbreaks in LTCFs reported to the Ministry of Health, Singapore in 2017.A test-negative design was used to estimate the ratio of the odds of testing positive for influenza among vaccinated individuals to the odds among unvaccinated individuals. The VE was calculated as (1-odds ratio) × 100%. For adjusted VE, the estimates were derived using logistic regression adjusted for age group, gender, month of illness, and number of days from date of illness onset till to swab collection date. Estimates by influenza subtypes and post-vaccination time periods (15–180 days & 181–365 days) were also calculated using stratified data.264 individuals, with 118 laboratory-confirmed influenza cases [32 A(H1N1)pdm09, 75 A(H3N2), 11 A(untypable)], were included in the analysis. No one was identified to be infected with influenza B. The overall adjusted VE estimate was 40.5% (95% CI: −12.2–68.5%), while the subtype-specific adjusted VE estimates were −43.4% (95% CI: −312.4–50.2%) against A(H1N1)pdm09 and 57.1% (95% CI: 5.7–80.5%) against A(H3N2). At 15–180 days post-vaccination period, the adjusted VEs were 59.3% (95% CI: 18.0–79.8%) against all influenza, 35.4% (95% CI: −123.5–81.3%) against A(H1N1)pdm09 and 67.9% (95% CI: 22.5–86.7%) against A(H3N2). Estimates were not significant at 181–365 days post-vaccination.The influenza vaccine showed varying effectiveness among individuals in Singapore’s LTCFs in 2017, with a higher effectiveness among those who were more recently vaccinated. It remains an important tool in preventing influenza infections, especially for those who are at high risk of influenza-related complications.

Accounting for the Spread of Vaccination Behavior to Optimize Influenza Vaccination Programs

Influenza vaccination is the most efficient approach to prevent influenza infection and its complications. While previous studies considered the externalities of vaccination arising from indirect protection for prediction and control of influenza infection, they often neglected another potential externality of a vaccinated individual – the effect on her environment's decision to become vaccinated. Here we model influenza vaccination as a socially contagious process. Our model uses a contact network we developed based on cellular data of 17 Billion records describing the location of 1.8 million Israeli cellphone users. The model was calibrated to high-quality longitudinal data of weekly influenza vaccination uptake and influenza diagnoses over seven years. We demonstrate how a simple coupled transmission-model accurately captures spatiotemporal patterns of both influenza vaccination uptake and influenza transmission. Our simulations indicate that modeling the vaccination spread alongside the propagation of the disease infection, coupled to each other, reveals complex underlying dynamics regarding the timing of the processes. Specifically, we show that higher overall vaccination coverage leads to a more rapid vaccination process and an earlier onset of the influenza activity. We prove this understanding to be useful to improve the timing of influenza vaccination programs.

Influenza vaccination of pregnant women in Paris, France: Knowledge, attitudes and practices among midwives.

IntroductionIn France, midwives have been authorized to prescribe vaccines since 2016. Yet vaccination coverage among pregnant women remains low. Understanding the knowledge, attitudes and practices of midwives regarding influenza vaccination could help improve coverage.MethodsA cross-sectional survey was conducted in 2017 among midwives practicing in the public and private sectors in Paris using an online questionnaire. Multivariate logistic regression analysis of the data was conducted.ResultsThe response rate was 31% (n = 208/669). Overall, knowledge of influenza vaccine recommendations and of vaccine safety and effectiveness was high except regarding new-born immunity and influenza vaccine characteristics. Only 10% of midwives systematically prescribed the vaccine. Reported influenza vaccine uptake among midwives was 39%.ConclusionEfforts to improve the knowledge of midwives regarding the safety and effectiveness of vaccinating pregnant women in order to prevent influenza infection in newborns are necessary. Increasing vaccine uptake in both midwives and pregnant women will require adjusting education strategies.

Efficient influenza A virus production in high cell density using the novel porcine suspension cell line PBG.PK2.1

Seasonal and pandemic influenza respiratory infections are still a major public health issue. Vaccination is the most efficient way to prevent influenza infection. One option to produce influenza vaccines is cell-culture based virus propagation. Different host cell lines, such as MDCK, Vero, AGE1.CR or PER.C6 cells have been shown to be a good substrate for influenza virus production. With respect to the ease of scale-up, suspension cells should be preferred over adherent cells. Ideally, they should replicate different influenza virus strains with high cell-specific yields. Evaluation of new cell lines and further development of processes is of considerable interest, as this increases the number of options regarding the design of manufacturing processes, flexibility of vaccine production and efficiency.Here, PBG.PK2.1, a new mammalian cell line that was developed by ProBioGen AG (Germany) for virus production is presented. The cells derived from immortal porcine kidney cells were previously adapted to growth in suspension in a chemically-defined medium. Influenza virus production was improved after virus adaptation to PBG.PK2.1 cells and optimization of infection conditions, namely multiplicity of infection and trypsin concentration. Hemagglutinin titers up to 3.24 log10(HA units/100 µL) were obtained in fed-batch mode in bioreactors (700 mL working volume). Evaluation of virus propagation in high cell density culture using a hollow-fiber based system (ATF2) demonstrated promising performance: Cell concentrations of up to 50 × 106 cells/mL with viabilities exceeding 95%, and a maximum HA titer of 3.93 log10(HA units/100 µL). Analysis of glycosylation of the viral HA antigen expressed showed clear differences compared to HA produced in MDCK or Vero cell lines. With an average cell-specific productivity of 5000 virions/cell, we believe that PBG.PK2.1 cells are a very promising candidate to be considered for next-generation influenza virus vaccine production.

Epidemiology, Diagnosis, Treatment, and Prevention of Influenza Infection in Oncology Patients.

Influenza infection causes increased morbidity and higher mortality in patients receiving treatment of underlying cancer, particularly in those with hematological malignancy or patients who have undergone hematopoietic stem-cell transplantation. The illness is characterized by seasonality and nonspecific clinical manifestations of upper respiratory infection at a time when other respiratory illnesses are common in the community, making the diagnosis challenging. However, accurate and timely diagnosis by new molecular techniques is crucial in the management of immunocompromised patients, because delays in initiating appropriate therapy can have devastating consequences. Emergence of viral resistance to currently used antiviral agents is of concern, particularly in immunocompromised hosts, and warrants continued monitoring and surveillance. Early and effective treatment improves outcomes, but optimal therapeutic strategies in patients with cancer are not well defined. Health care and research efforts should focus on defining treatment guidelines in patients with cancer and attempt to improve on current vaccination strategies.

Novel Rigid Glycomimetics to Inhibit Influenza Infection

Small‐molecule anti‐influenza agents, such as zanamivir and oseltamivir are neuraminidase (NA) inhibitors limit the release of progeny virions from infected cells through competitive binding to the viral NA. However, these drugs do not block infection. Vaccination is the most common approach for preventing influenza infection, but vaccine creation takes approximately 6 months and requires prior knowledge of the circulating virus strains. The impact of this limitation was evident in the 2009 swine flu pandemic, against which the seasonal vaccine was completely ineffective. The urgent need to develop complementary strategies to vaccination or NA inhibition is emphasized by the fact that between 2006 and 2009 seasonal flu developed almost complete resistance to oseltamivir, resulting from a single spontaneous mutation in the viral NA.As a potential alternative to current flu antivirals, we are developing glycomimetics that block the interaction between the viral hemagglutinin (HA) and the host glycans that serve as flu‐receptors. This interaction is essential for viral adhesion, and the universal receptor for flu A [15] and B [16] viruses is Sia‐Gal (sialic acid, Sia, a.k.a. neuraminic acid, linked to galactose, Gal). HAs from either human (H1N1) or avian‐infective (N5N1) flu strains bind to di‐ or trisaccharides terminating in Sia‐Gal regardless of whether the Sia‐Gal linkage is α2,6 or α2,3. This observation suggested that a small Sia‐Gal glycomimetic might be developed that could inhibit a broad range of flu A strains, including flu B, and was critical in the design of our glycomimetic framework (FB127).Here were report that FB127 shows dose‐dependent inhibition of the infection of MDCK cells by a range of flu viruses from group 1 (H1N1, H5N1), group 2 (H3N2), and flu B, and that the influenza neutralizing ability of FB127 is within the same range as reported for glycodendrimers. Because FB127 is a synthetic small molecule, it can be rationally modified, and manufactured with a high degree of quality control and reproducibility. In this regard, FB127 is amenable to a number of formulations, including aerosol, oral, and intravenous routes that provide great flexibility in drug delivery.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Conserved HA-peptide NG34 formulated in pCMV-CTLA4-Ig reduces viral shedding in pigs after a heterosubtypic influenza virus SwH3N2 challenge.

Swine influenza viruses (SIVs), the causal agents of swine influenza, are not only important to control due to the economic losses in the swine industry, but also can be pandemic pathogens. Vaccination is one of the most relevant strategies to control and prevent influenza infection. Current human vaccines against influenza induce strain-specific immunity and annual update is required due to the virus antigenic shift phenomena. Previously, our group has reported the use of conserved hemagglutinin peptides (HA-peptides) derived from H1-influenza virus as a potential multivalent vaccine candidate. Immunization of swine with these HA-peptides elicited antibodies that recognized and neutralized heterologous influenza viruses in vitro and demonstrated strong hemagglutination-inhibiting activity. In the present work, we cloned one HA-peptide (named NG34) into a plasmid fused with cytotoxic T lymphocyte-associated antigen (CTLA4) which is a molecule that modifies T cell activation and with an adjuvant activity interfering with the adaptive immune response. The resulting plasmid, named pCMV-CTLA4-Ig-NG34, was administered twice to animals employing a needle-free delivery approach. Two studies were carried out to test the efficacy of pCMV-CTLA4-Ig-NG34 as a potential swine influenza vaccine, one in seronegative and another in seropositive pigs against SIV. The second one was aimed to evaluate whether pCMV-CTLA4-Ig-NG34 vaccination would overcome maternally derived antibodies (MDA). After immunization, all animals were intranasally challenged with an H3N2 influenza strain. A complete elimination or significant reduction in the viral shedding was observed within the first week after the challenge in the vaccinated animals from both studies. In addition, no challenged heterologous virus load was detected in the airways of vaccinated pigs. Overall, it is suggested that the pCMV-CTLA4-Ig-NG34 vaccine formulation could potentially be used as a multivalent vaccine against influenza viruses.

Efficient filtration strategies for the clarification of influenza virus-like particles derived from insect cells

Vaccination remains the most effective available tool for preventing influenza infection, which affects millions of people annually. The virus is constantly mutating, requiring annual immunization. Vaccine production should be achieved in a very short period to cope with global requirements for seasonal treatment. Moreover, pandemic outbreaks require quick production of large amounts of vaccines. Virus-like particles (VLP) have become a promising alternative for influenza vaccines due to their versatility, immunogenicity and safety profile. However, the diversity of virus surface epitopes contributes to a variability in downstream purification, that could ultimately affect manufacturability and necessitate yearly redevelopment of processes. Therefore, there is a demand for development of better and faster influenza vaccine bioprocesses. Clarification is a critical step, not well characterized for most of the purification processes, but with a strong impact on the downstream performance. For that purpose, we have undertaken an effort to develop a clarification platform for the manufacturing of several influenza strains, mono and multivalent, at different production scales (1L–11L). Both normal and tangential flow filtration approaches were evaluated in terms of product recovery and removal of impurities. The selected clarification train results in essentially 100% product recovery with a turbidity value below 10 NTU, as well as high impurity clearance. Most importantly, these results are independent of strain, cell viability and turbidity at harvest time. The developed clarification framework may be applied to different influenza strains, contributing to a speed-up of vaccine manufacturing.

Can the Health Belief Model and moral responsibility explain influenza vaccination uptake among nurses?

The aim of this study was to examine the prevalence and the factors associated with influenza vaccination among nurses in Hong Kong based on the Health Belief Model. The role of moral responsibility was also examined. Influenza vaccination is the most effective way to prevent influenza infection. Nurses are recommended to receive influenza vaccination annually. However, the rate of vaccination among nurses in Hong Kong is low. A cross-sectional study. A survey was conducted among 214 nurses between January - March 2017. The prevalence of having ever received influenza vaccination, having received influenza vaccination in the last influenza season and having intention to receive influenza vaccination in the coming influenza season were 64.5%, 29.0% and 23.3% respectively. Results from multiple stepwise logistic regressions showed that perceived benefits of influenza vaccination and having received recommendations from colleagues were associated with higher chances of having ever received influenza vaccination. Perceived susceptibility of influenza, perceived benefits of influenza vaccination and perceived moral responsibility were associated with higher chances of having received influenza vaccination in the last influenza season, whereas perceived barriers of influenza vaccination were associated with lower chances. Furthermore, perceived susceptibility of influenza and perceived benefits of influenza vaccination were associated with higher chances of having the intention to receive influenza vaccination in the coming influenza season, whereas perceived barriers were associated with lower chances. The moderating effect of perceived moral responsibility was not significant. Health promotion should make use of the Health Belief Model and increase moral responsibility to increase influenza vaccination rate among nurses.

Effectiveness of hand hygiene practices in preventing influenza virus infection in the community setting: A systematic review.

BackgroundHand hygiene is known to be an effective infection prevention and control measure in health care settings. However, the effectiveness of hand hygiene practices in preventing influenza infection and transmission in the community setting is not clear.ObjectiveTo identify, review and synthesize available evidence on the effectiveness of hand hygiene in preventing laboratory-confirmed or possible influenza infection and transmission in the community setting.MethodsA systematic review protocol was established prior to conducting the review. Three electronic databases (MEDLINE, Embase and the Cochrane Library) were searched to identify relevant studies. Two reviewers independently screened the titles, abstracts and full-texts of studies retrieved from the database searches for potential eligibility. Data extraction and quality assessment of included studies were performed by a single reviewer and validated by a second reviewer. Included studies were synthesized and analyzed narratively.ResultsA total of 16 studies were included for review. Studies were of low methodological quality and there was high variability in study design, setting, context and outcome measures. Nine studies evaluated the effectiveness of hand hygiene interventions or practices in preventing laboratory-confirmed or possible influenza infection in the community setting; six studies showed a significant difference, three studies did not. Seven studies assessed the effectiveness of hand hygiene practices in preventing laboratory-confirmed or possible influenza transmission in the community setting; two studies found a significant difference and five studies did not.ConclusionThe effectiveness of hand hygiene against influenza virus infection and transmission in the community setting is difficult to determine based on the available evidence. In light of its proven effectiveness in other settings, there is no compelling evidence to stop using good hand hygiene practice to reduce the risk of influenza infection and transmission in the community setting.

A Perspective on Nanoparticle Universal Influenza Vaccines.

Annually recurring seasonal influenza causes massive economic loss and poses severe threats to public health worldwide. The current seasonal influenza vaccines are the most effective means of preventing influenza infections but possess major weaknesses. Seasonal influenza vaccines require annual updating of the vaccine strains. However, it is an unreachable task to accurately predict the future circulating strains. Vaccines with mismatched strains dramatically compromise the vaccine efficacy. In addition, the seasonal influenza vaccines are ineffective against an unpredictable pandemic. A universal influenza vaccine would overcome these weaknesses of the seasonal vaccines and abolish the threat of influenza pandemics. One approach under investigation is to design influenza vaccine immunogens based on conserved, type-specific amino acid sequences and conformational epitopes, rather than strain-specific. Such vaccines can elicit broadly reactive humoral and cellular immunity. Universal influenza vaccine development has intensively employed nanotechnology because the structural and morphological properties of nanoparticles dramatically improve vaccine immunogenicity and the induced immunity duration. Layered protein nanoparticles can decrease off-target immune responses, fine-tune antigen recognition and processing, and facilitate comprehensive immune response induction. Herein, we review the designs of effective nanoparticle universal influenza vaccines, the recent discoveries of specific nanoparticle features that contribute to immunogenicity enhancement, and recent progress in clinical trials.

Impact of Pharmacy-Initiated Interventions on Influenza Vaccination Rates in Pediatric Solid Organ Transplant Recipients.

In solid organ transplant (SOT) recipients, influenza infection can lead to subsequent graft dysfunction and death. Vaccination is the most effective approach to preventing influenza infection; however, vaccination rates are low, and interventions to optimize vaccine coverage are needed. The purpose of this study was to evaluate if pharmacy-initiated screening and recommendations for influenza immunization improve the rate of vaccination in pediatric SOT recipients. We performed a retrospective pre-post chart review of all kidney, liver, and heart transplant recipients followed by Children's Healthcare of Atlanta/Emory University transplant services between September 1, 2011, and February 16, 2017. Influenza vaccination coverage and influenza rates before (2011-2013) and after (2014-2016) the implementation of pharmacy-driven vaccination in SOT recipients were assessed. A total of 822 patients were included; 101 (13%) of these patients were diagnosed with influenza, and 40 (5%) were hospitalized secondarily during the study period. Vaccination coverage increased over time (144 [36%] patients vaccinated in 2011 vs 430 [74%] in 2016; P < .001). Influenza diagnosis rates decreased between the 2 eras (P = .006). The median time in which 50% of the population was vaccinated decreased over time from 163 days in 2012 to 94 days in 2016 (P < .001). Within the constraints of the pre-post study design, we observed a significant increase in influenza vaccination rates after implementation of a transplant pharmacy-initiated screening and vaccination program. The number of patients diagnosed with influenza and the time to vaccination decreased after our pharmacy intervention. All efforts should be made to increase compliance with influenza vaccination; pharmacy-initiated interventions can improve protection against influenza infection in pediatric SOT recipients.

Prevalence, knowledge, attitude, and practices associated with influenza vaccination among healthcare workers in primary care centers in Jazan, Saudi Arabia: A crosssectional study

Purpose: To assess the prevalence, knowledge, attitude and practices of health care workers (HCWs) in Jazan Province regarding the annual influenza vaccination program.Methods: A cross-sectional, self-administered questionnaire-based study was conducted among HCWs (n = 368) at the primary 18 health care centers in Jazan, Saudi Arabia during the period January – April, 2016.Results: The overall vaccination coverage was 87.0 % in the previous year and 79.9 % in the last 5 years. In all, 97 % of males and 59.5 % of females considered influenza as a serious disease (p = 0.005). Regarding prevention of influenza infection, 91.2 % of respondents believed that HCWs were at risk of influenza infection, while 62.5 % considered vaccination as the best preventive measure (p = 0.003). The most common reasons for receiving vaccine were “to protect oneself or one’s family” (99.4 %), while the most common reason for not taking the vaccine was “fear of side effects” (49 %).Conclusion: HCWs exhibit positive attitudes toward influenza vaccine, and notwithstanding the high vaccine coverage in Jazan Province. However, influenza vaccine campaigns should include information to enhance the awareness of HCWs about the risk of exposure to influenza, and information about the adverse reactions to influenza vaccine.Keywords: Healthcare workers, Influenza vaccine, Risk of exposure, Adverse reactions.

A systematic review and meta-analysis of the direct epidemiological and economic effects of seasonal influenza vaccination on healthcare workers.

BackgroundInfluenza vaccination is a commonly used intervention to prevent influenza infection in healthcare workers (HCWs) and onward transmission to other staff and patients. We undertook a systematic review to synthesize the latest evidence of the direct epidemiological and economic effectiveness of seasonal influenza vaccination among HCW.MethodsWe conducted a systematic search of MEDLINE/PubMed, Scopus, and Cochrane Central Register of Controlled Trials from 1980 through January 2018. All studies comparing vaccinated and non-vaccinated (i.e. placebo or non-intervention) groups of HCWs were included. Research articles that focused on only patient-related outcomes or monovalent A(H1N1)pdm09 vaccines were excluded. Two reviewers independently selected articles and extracted data. Pooled-analyses were conducted on morbidity outcomes including laboratory-confirmed influenza, influenza-like illnesses (ILI), and absenteeism. Economic studies were summarized for the characteristics of methods and findings.ResultsThirteen articles met eligibility criteria: three articles were randomized controlled studies and ten were cohort studies. Pooled results showed a significant effect on laboratory-confirmed influenza incidence but not ILI. While the overall incidence of absenteeism was not changed by vaccine, ILI absenteeism was significantly reduced. The duration of absenteeism was also shortened by vaccination. All published economic evaluations consistently found that the immunization of HCW was cost saving based on crude estimates of avoided absenteeism by vaccination. No studies, however, comprehensively evaluated both health outcomes and costs of vaccination programs to examine cost-effectiveness.DiscussionOur findings reinforced the influenza vaccine effects in reducing infection incidence and length of absenteeism. A better understanding of the incidence of absenteeism and comprehensive economic program evaluations are required to ensure the best possible management of ill HCWs and the investment in HCW immunization in increasingly constrained financial environments. These steps are fundamental to establish sustainability and cost-effectiveness of vaccination programs and underpin HCW immunization policy.

Improving influenza vaccination rates in pediatric subspecialty clinics

Specific Aim Influenza-associated mortality accounts for scores of pediatric deaths each year and patients with complex medical conditions are at highest risk for complications. Annual influenza vaccination is the most effective method for preventing influenza infection. Our goal was to improve influenza vaccination screening and delivery for pediatric subspecialty patients at the University of Chicago Comer Children’s Hospital. By creating an enhanced clinical decision support (CDS) tool to notify providers if a patient may need a vaccine and through development of a monthly clinic-level feedback tool, we hoped to increase screening by …

Development of Pyrosequencing-Based Assay for Analyzing the Origin of Genes in Preparing Reassortant LAIV Candidates

Live attenuated influenza vaccine (LAIV) is an effective measure to prevent influenza infection. The vaccine strain for LAIV is derived by reassortment of epidemic influenza strain with cold-adapted master donor virus (MDV) in developing chicken embryos. Molecular analysis of genomic composition of generated reassortants to select appropriate candidate for LAIV is a critical stage of vaccine strain development. Method of analysis permitting quick and precise detection of the genome composition of reassortants is required. The purpose of this study was to develop pyrosequencing-based assay using PyroMark Q24 for analysis of the origin of genes in preparing reassortant LAIV candidates for influenza A vaccine strains based on A/Leningrad/134/17/57 master donor virus and influenza B vaccine strains based on B/USSR/60/69 or B/Leningrad/14/77/55 master donor viruses, respectively. Objectives included development of primers set for genotyping of influenza A and B reassortants by pyrosequencing, establishing optimal dispensation order and assessment of effectiveness of protocol application for detecting the source of genes in virus samples. We have shown that a unified genome analysis protocol using PyroMark Q24 system is able to detect the source of internal genes in reassortant influenza strain by pyrosequencing. It allows analyzing the genome composition by a sensitive and specific innovative method in the first stages of vaccine strain development.

Universal Vaccines and Vaccine Platforms to Protect against Influenza Viruses in Humans and Agriculture.

Influenza virus infections pose a significant threat to public health due to annual seasonal epidemics and occasional pandemics. Influenza is also associated with significant economic losses in animal production. The most effective way to prevent influenza infections is through vaccination. Current vaccine programs rely heavily on the vaccine's ability to stimulate neutralizing antibody responses to the hemagglutinin (HA) protein. One of the biggest challenges to an effective vaccination program lies on the fact that influenza viruses are ever-changing, leading to antigenic drift that results in escape from earlier immune responses. Efforts toward overcoming these challenges aim at improving the strength and/or breadth of the immune response. Novel vaccine technologies, the so-called universal vaccines, focus on stimulating better cross-protection against many or all influenza strains. However, vaccine platforms or manufacturing technologies being tested to improve vaccine efficacy are heterogeneous between different species and/or either tailored for epidemic or pandemic influenza. Here, we discuss current vaccines to protect humans and animals against influenza, highlighting challenges faced to effective and uniform novel vaccination strategies and approaches.

National burden of hospitalized and non-hospitalized influenza-associated severe acute respiratory illness in Kenya, 2012-2014.

BackgroundInfluenza‐associated respiratory illness was substantial during the emergence of the 2009 influenza pandemic. Estimates of influenza burden in the post‐pandemic period are unavailable to guide Kenyan vaccine policy.ObjectivesTo update estimates of hospitalized and non‐hospitalized influenza‐associated severe acute respiratory illness (SARI) during a post‐pandemic period (2012‐2014) and describe the incidence of disease by narrow age categories.MethodsWe used data from Siaya County Referral Hospital to estimate age‐specific base rates of SARI. We extrapolated these base rates to other regions within the country by adjusting for regional risk factors for acute respiratory illness (ARI), regional healthcare utilization for acute respiratory illness, and the proportion of influenza‐positive SARI cases in each region, so as to obtain region‐specific rates.ResultsThe mean annual rate of hospitalized influenza‐associated SARI among all ages was 21 (95% CI 19‐23) per 100 000 persons. Rates of non‐hospitalized influenza‐associated SARI were approximately 4 times higher at 82 (95% CI 74‐90) per 100 000 persons. Mean annual rates of influenza‐associated SARI were highest in children <2 years of age with annual hospitalization rates of 147 (95% CI of 134‐160) per 100 000 persons and non‐hospitalization rates of 469 (95% CI 426‐517) per 100 000 persons. For the period 2012‐2014, there were between 8153 and 9751 cases of hospitalized influenza‐associated SARI and 31 785‐38 546 cases of non‐hospitalized influenza‐associated SARI per year.ConclusionsThe highest burden of disease was observed among children <2 years of age. This highlights the need for strategies to prevent influenza infections in this age group.

Influenza vaccine effectiveness against medically attended influenza illness in Beijing, China, 2014/15 season

ABSTRACT Influenza vaccination is the most effective way of preventing influenza infections but its coverage is extremely low in China. Poor influenza vaccine effectiveness (VE) was reported in the 2014/15 season in some Northern Hemisphere countries with a predominance of H3N2 viruses belonging to the 3C.2a clade. However, there is limited information regarding the preventive effect of influenza vaccination for the same season in China, in which H3N2 viruses belonging to the 3C.3a clade predominated. Through influenza virological surveillance in Beijing, China during the 2014/15 season, we estimated the influenza VE against medically attended influenza-like illness (ILI) associated with laboratory-confirmed influenza virus infection using a test-negative design, and the effect of prior vaccination on current vaccination was examined. In total, 9297 patients with ILI were enrolled in this study. Among them, 3434 (36.9%) tested positive for influenza viruses: 2167 (63.1%) for A(H3N2), 1261 (36.7%) for influenza B, and 3 (0.1%) for A(H1N1)pdm09. The adjusted VE was estimated as −25% (95% CI: −70%, 8%) against A(H3N2) and −8% (95% CI: −50%, 23%) against B, with an overall VE of −18% (95% CI: −49%, 6%). The overall VE estimate for patients who received 2014/15 vaccination only was −12% (−57%, 20%), while VE for patients who received both 2013/14 and 2014/15 vaccinations was −27% (−72%, 7%). There was no evidence that the influenza vaccine protected vaccinees against medically attended influenza in Beijing, China during the 2014/15 season.