Influenza-related Complications Research Articles

Safety of quadrivalent recombinant influenza vaccine in pregnant persons and their infants

BackgroundThe Advisory Committee on Immunization Practices (ACIP) and the American College of Obstetricians and Gynecologists (ACOG) recommend that all pregnant persons receive any licensed, recommended, and age-appropriate inactivated influenza vaccine (SD-IIV) or recombinant influenza vaccine (RIV) to protect against influenza and influenza-related complications. RIV was safe and efficacious in pre- and postlicensure studies, however there is limited RIV safety data in pregnant persons. ObjectiveTo evaluate the safety of quadrivalent recombinant influenza vaccine (RIV4) versus a quadrivalent standard-dose, inactivated influenza (SD-IIV4) in a large cohort of pregnant persons and their infants. Study DesignThis postlicensure observational safety study conducted at Kaiser Permanente Northern California evaluated the subset of pregnant persons vaccinated in routine care as part of a larger cluster-randomized vaccine effectiveness study comparing RIV4 vs. SD-IIV4 (ClinicalTrials.gov NCT03694392). We identified pregnancy (spontaneous abortion, preterm labor, stillbirth/fetal death, congenital/fetal anomalies detected during pregnancy, eclampsia/pre-eclampsia, placental abruption), birth (preterm birth, low birth weight, small for gestational age), and neonatal/infant outcomes (infant death, failure to thrive, congenital anomalies detected after delivery) using diagnostic codes among pregnant persons ≥18 years immunized with RIV4 or SD-IIV4 during the 2018/19 and 2019/20 influenza seasons and their infants. We used conditional logistic regression adjusted for age group, race, ethnicity, trimester of influenza vaccination, comorbidities, and BMI, stratified by gestational age to estimate the odds ratio (OR) of pregnancy outcomes following vaccination with RIV4 vs. SD-IIV4. Using logistic regression, we separately estimated the adjusted OR of birth and neonatal/infant outcomes in the first year of life (eg, death) in infants of RIV4 vs. SD-IIV4 vaccinated pregnant persons. ResultsThe study population included 48,781 pregnant persons (RIV4 = 14,981; SD-IIV4 = 33,800) and 47,394 live births (RIV4 = 14,538; SD-IIV4 = 32,856). There was no statistical difference in any pregnancy outcome or in birth and neonatal/infant outcome between RIV4 vs. SD-IIV4 vaccinated pregnant persons and their infants. ConclusionCompared with receipt of a SD-IIV4 during pregnancy, this large study did not identify any pregnancy, birth, or neonatal/infant safety concerns following receipt of a RIV4 during pregnancy and demonstrates that the safety of RIV4 in pregnancy was similar to SD-IIV4. This study provides additional evidence regarding the safety of influenza vaccination in pregnant persons and further supports ACIP and ACOG recommendations that all pregnant persons receive an inactivated or recombinant influenza vaccine.

Consensus statements for influenza awareness, prevention, and vaccination in Pakistan.

Influenza is a serious underestimated viral infection in Pakistan and influenza vaccination and vaccination awareness are low. The current work aimed to develop consensus on influenza epidemiology, prevention, vaccination, and awareness in Pakistan. A systematic literature search was conducted to develop recommendations on influenza vaccines in Pakistan. Experts' feedback was incorporated using the modified Delphi method. A three-step process was used, with 18 experts from different specialties from Pakistan who participated in voting rounds to achieve a minimum 75% agreement level. Pakistan has a low-immunization-rate and is susceptible to serious influenza outbreaks and influenza-related complications. Influenza circulates year-round in Pakistan but peaks during January and February. The subtype A/H1N1 is predominant. The experts urged vaccination in all individuals ≥ 6 months of age and with no contraindications. They highlighted special considerations for those with comorbidities and specific conditions. The experts agreed that the inactivated influenza vaccine is safe and efficient in pregnant women, immunocompromised, and comorbid respiratory and cardiovascular patients. Finally, the experts recommended conducting promotional and educational programs to raise awareness on influenza and vaccination. This is the first regional consensus on influenza and influenza vaccination in Pakistan with experts' recommendations to increase influenza vaccination and decrease influenza cases and its associated detrimental effects.

Antivirals to prepare for surges in influenza cases: an economic evaluation of baloxavir marboxil for the Netherlands.

We perform a cost-effectiveness analysis (CEA) and budget impact analysis (BIA) of baloxavir marboxil compared to current care in the Netherlands for patients at risk of influenza-related complications, including patients with comorbidities and the elderly. In the CEA, a decision tree model was developed to assess the cost-effectiveness of baloxavir marboxil for a cohort of 52-year-olds from a societal perspective. A lifetime horizon was taken by incorporating the quality-adjusted life expectancy. The BIA included different epidemiological scenarios, estimating different plausible epidemiological scenarios for seasonal influenza considering the whole Dutch population with an increased risk of influenza complications. The base-case ICER was estimated to be €8,300 per QALY. At the willingness-to-pay threshold of €20,000 per QALY, the probability of being cost effective was 58%. The base-case expected budget impact was €5.7 million on average per year, ranging from €1.5 million to €10.5 million based on the severity of the influenza epidemic and vaccine effectiveness. In the Netherlands, baloxavir is a cost-effective treatment option for seasonal influenza, with a base-case ICER of €8,300 per QALY for the population aged 60years and over and patients at high risk of influenza-related complications. For a large part, this ICER is driven by the reduction of the illness duration of influenza and productivity gains in the working population.

Factors Associated With Influenza Vaccination During Pregnancy: A Real-World Evidence-Based Study.

Pregnant women are at increased risk of influenza-related complications. However, the rate of influenza vaccination among pregnant women in Taiwan is low. By analyzing real-world data in this study, we investigated the factors associated with influenza vaccination during pregnancy in Taiwan. This study was a cross-sectional study. We collected real-world data from 2 databases in Taiwan: the Birth Certificate Database and the National Health Insurance Research Database. The study population was pregnant between October 2014 and December 2016 in Taiwan. The multivariate logistic regression was performed to identify factors associated with influenza vaccination, including maternal sociodemographics, trimester, comorbidities, and health-care utilization. The vaccination rate of among pregnant women was 8.2%. Factors significantly associated with a high likelihood of influenza vaccination were age between 30 and 34 years (odds ratio [OR]: 1.14; 95% confidence interval [CI]: 1.10-1.19), second trimester (OR: 1.80; 95% CI: 1.75-1.85), income equal to or exceeding NT$ 38 201 (OR: 1.92; 95% CI: 1.86-1.99), hypertension (OR: 1.16; 95% CI: 1.05-1.29), cardiovascular disease (OR: 1.29; 95% CI: 1.17-1.42), autoimmune disease (OR: 1.47; 95% CI: 1.38-1.58), and chronic pulmonary disease (OR: 1.24; 95% CI: 1.18-1.31). A low level of urbanization, at least 1 hospitalization in the previous year, and the presence of pregnancy complications (eg, gestational diabetes, preeclampsia, and placenta previa) were associated with a lower likelihood rate of influenza vaccination. The influenza vaccination rate among pregnant women in Taiwan was low. Age, gestational age, income level, urbanization level, hypertension, cardiovascular disease, autoimmune disease, chronic pulmonary disease, and pregnancy complications may be associated with influenza vaccination among pregnant women.

Knowledge, attitudes, beliefs and practices of pregnant women towards the influenza vaccine in Trinidad.

Pregnant women and their babies are at increased risk of influenza-related complications. The World Health Organisation recommends influenza vaccination to this high-risk population as the highest priority. A knowledge, attitudes,beliefs, and practices (KAP) of pregnant women towards the influenza vaccine in Trinidad. It was disseminated to 480 pregnant women attending the clinic and completed by 146 yielding a response rate of 30%. Women who received the vaccine in a past pregnancy were nine times more likely to consider taking the vaccine in the current pregnancy. There was a statistically significant difference in vaccine uptake based on the source of information received by participants about the influenza vaccine (χ2 (3) = 9.864, P = 0.020), with the highest mean score for uptake shown in women who received information from a health care provider. A moderate, positive correlation was found between knowledge and vaccine uptake (rs (143) =0.430, P < 0.01), a weak, positive correlation between perceived susceptibility and vaccine uptake (rs (143) = 0.264, P < 0.01), and a weak, positive correlation between knowledge and perceived susceptibility (rs (143) = 0.229, P < 0.01). The study findings highlight that the source of information significantly influences vaccine uptake, with health care providers being the most influential source. This underscores the role of primary care physicians in providing accurate and up-to-date information about influenza vaccination to pregnant women. There is a need for accurate information and recommendations to be given to pregnant women by all health care workers including primary care physicians in order to increase vaccine uptake and reduce maternal and neonatal morbidity and mortality.

Influenza's burden: an umbrella review about complications, hospitalizations and mortality

Abstract Background Influenza virus infection is a major cause of morbidity and mortality worldwide, placing high costs to health systems, yet the quantification of its clinical burden remains debated and undervalued. We conducted an umbrella review to provide a summary of current knowledge on the topic. Methods We searched PubMed-MEDLINE, Web of Science, and the Cochrane library for both systematic reviews and metanalysis of observational studies reporting quantitative assessment of seasonal influenza clinical burden in terms of complications, hospitalizations, and deaths, published up to 30th April 2022. English records were considered for inclusion. We collated together quantitative measures across different outcomes. Results We identified 17 systematic reviews and 10 systematic reviews with meta-analyses published between 2005 and 2022, which included 1321 primary studies conducted from 1918 to 2020 and covering more than 15 million subjects. Of the 27 systematic reviews, 9 (33%) focused on the general population of all ages, 3 (11%) on subjects aged 18 years or older, and 10 (37%) on the paediatric population. Lastly, three reviews (11%) focused on pregnant women, and 2 (7%) on other special populations. Twenty-one (78%) reviews included studies from different countries. Preliminary results show children aged ≤5 years, and adults aged ≥65 mostly contribute to the morbidity and mortality burden of influenza: the hospitalization rate for influenza-related complications is higher in paediatric subjects than in adults (0.27-10% vs 0.02-0.43%) while the highest mortality rate occurs in over65, ranging from 0.12% at community level to 13% among inpatients. Results suggest also a triggering role by influenza for hearth attack in at-cardiovascular risk patients. Conclusions Despite variability in estimates, depending on the setting, the geographic area, and the population considered, influenza carries a significant clinical burden, especially - but not only - in fragile groups. Key messages • Influenza still poses a significant threat to health systems, which should be addressed with appropriate preventive strategies. • The best preventive strategy to reduce the flu burden is vaccination, especially in at-risk groups.

Progress in research of influenza vaccination in pregnant women

Influenza is an acute respiratory infectious disease caused by influenza virus. Pregnancy is associated with physiologic and immunological changes that may increase the risk for influenza virus infection and influenza-related complications. Influenza vaccination is the most effective way to prevent influenza virus infection. WHO and many countries have classified pregnant women as a priority population for influenza vaccination, however, there are still many challenges for promoting influenza vaccination in pregnant women in China, influenza vaccination coverage in pregnant women remains low and some influenza vaccine package inserts list pregnancy as an absolute contraindication. In this paper, we summarize the research progress in the effects of influenza infection and influenza vaccination during pregnancy both at home and abroad, then discuss the strategies to promote influenza vaccination in pregnancy for the purpose of providing reference for the related research and policy development in China.

Real-World Evidence in Cost-Effectiveness Analysis of Enhanced Influenza Vaccines in Adults ≥ 65 Years of Age: Literature Review and Expert Opinion.

Influenza vaccination can benefit most populations, including adults ≥ 65 years of age, who are at greater risk of influenza-related complications. In many countries, enhanced vaccines, such as adjuvanted, high-dose, and recombinant trivalent/quadrivalent influenza vaccines (aTIV/aQIV, HD-TIV/HD-QIV, and QIVr, respectively), are recommended in older populations to provide higher immunogenicity and increased relative vaccine efficacy/effectiveness (rVE) than standard-dose vaccines. This review explores how efficacy and effectiveness data from randomized controlled trials and real-world evidence (RWE) are used in economic evaluations. Findings from published cost-effectiveness analyses (CEA) on enhanced influenza vaccines for older adults are summarized, and the assumptions and approaches used in these CEA are assessed alongside discussion of the importance of RWE in CEA. Results from many CEA showed that adjuvanted and high-dose enhanced vaccines were cost-effective compared with standard vaccines, and that differences in rVE estimates and acquisition price may drive differences in cost-effectiveness estimates between enhanced vaccines. Overall, RWE and CEA provide clinical and economic rationale for enhanced vaccine use in people ≥ 65 years of age, an at-risk population with substantial burden of disease. Countries that consider RWE when making vaccine recommendations have preferentially recommended aTIV/aQIV, as well as HD-TIV/HD-QIV and QIVr, to protect older individuals.

Cost-effectiveness of routine annual influenza vaccination by age and risk status

BackgroundThe epidemiology of circulating seasonal influenza strains changed following the 2009 pandemic influenza A(H1N1). A universal influenza vaccination recommendation has been implemented and new vaccine types have become available post-2009. The objective of this study was to evaluate the cost-effectiveness of routine annual influenza vaccination in the context of this new evidence. MethodsA state transition simulation model was constructed to estimate the health and economic outcomes of influenza vaccination compared to no vaccination for hypothetical US cohorts stratified by age and risk status. Model input parameters were derived from multiple sources, including post-2009 vaccine effectiveness data from the US Flu Vaccine Effectiveness Network. The analysis used societal and healthcare sector perspectives and a one-year time horizon, except permanent outcomes were also included. The primary outcome was the incremental cost-effectiveness ratio (ICER) in dollars per quality-adjusted life years (QALYs) gained. ResultsCompared to no vaccination, vaccination yielded ICERs lower than $95,000/QALY for all age and risk groups, except for non-high-risk adults 18–49 years ($194,000/QALY). Vaccination was cost-saving for adults ≥50 years at higher risk for influenza-related complications. Results were most sensitive to changes in the probability of influenza illness. Performing the analysis from the healthcare sector perspective, excluding vaccination time costs, delivering vaccinations in lower-cost settings, and including productivity losses improved the cost-effectiveness of vaccination. Sensitivity analysis revealed that vaccination remains below $100,000/QALY for older persons ≥65 years at vaccine effectiveness estimates as low as 4 %. ConclusionsCost-effectiveness of influenza vaccination varied by age and risk status and was less than $95,000/QALY for all subgroups, except for non-high-risk working-age adults. Results were sensitive to the probability of influenza illness and vaccination was more favorable under certain scenarios. Vaccination for higher risk subgroups resulted in ICERs below $100,000/QALY even at low levels of vaccine effectiveness or circulating virus.

Summary of the National Advisory Committee on Immunization (NACI) Statement-Recommendations on Fractional Influenza Vaccine Dosing in the Event of a Shortage: Pandemic preparedness.

At the commencement of a pandemic, it is important to consider the impact of respiratory infections on the health system and the possibility of vaccine shortages due to increased demand. In the event of an influenza vaccine shortage, a strategy for administration of fractional influenza vaccine doses might be considered. This article reviews the available evidence for efficacy, effectiveness, immunogenicity and safety of fractional influenza vaccine dosing, and summarizes the National Advisory Committee on Immunization (NACI) recommendations on fractional dosing strategies by public health programs in Canada. Two rapid literature reviews were undertaken to evaluate the efficacy, effectiveness, immunogenicity and safety of fractional influenza vaccine dosing via the intramuscular or intradermal route. The NACI evidence-based process was used to assess the quality of eligible studies, summarize and analyze the findings, and apply an ethics, equity, feasibility and acceptability lens to develop recommendations. There was limited evidence for the effectiveness of fractional influenza vaccine dosing. Fractional dosing studies were primarily conducted in healthy individuals, mainly young children and infants, with no underlying chronic conditions. There was fair evidence for immunogenicity and safety. Feasibility issues were identified with intradermal use in particular. NACI recommended that, in the event of a significant population-level shortage of influenza vaccine, a full-dose influenza vaccine should continue to be used, and existing vaccine supply should be prioritized for those considered to be at high risk or capable of transmitting to those at high risk of influenza-related complications or hospitalizations. NACI recommended against the use of fractional doses of influenza vaccine in any population.

Different dosages of methylprednisolone therapy for acute necrotizing encephalopathy of childhood: a 6-year multicenter retrospective study.

Different dosages of methylprednisolone therapy for acute necrotizing encephalopathy of childhood: a 6-year multicenter retrospective study.

Influenza vaccination trend and related factors among patients with diabetes in Korea: Analysis using a nationwide database.

Subjects with diabetes are at higher risk of serious influenza-related complications. We aimed to investigate the yearly trend of influenza vaccination and factors associated with being unvaccinated for influenza in subjects with diabetes using a nationwide observational study performed within the recent decade. Among 105,732 subjects from the Korea National Health and Nutrition Examination Survey between 2007 and 2019, 8,632 with diabetes were included. We investigated the yearly trend of influenza vaccination and factors associated with being unvaccinated for influenza. During the study period, the prevalence of influenza vaccination in subjects with diabetes showed a tendency to increase every year, reaching almost 60% in 2019, which was higher than the rate in subjects without diabetes. Younger age (adjusted hazard ratio (aHR) [95% CI] 11.29 [8.63-14.75] for < 50 years; 6.16 [5.21-7.29] for 50-65 years), male (aHR 1.67 [1.52-1.87]), current smoker (aHR 1.31 [1.00-1.72], lower-income status (aHR 1.46 [1.17, 1.84]), and high education level (aHR 1.30 [1.01-1.67]) were associated with being unvaccinated. Also, a poorer glycemic control with HbA1c ≥ 9% was found to be correlated with unvaccinated status (aHR 1.48 [1.15-1.90]). The influenza vaccination rate is still unsatisfactory in subjects with diabetes. Young age, males, low-income level, high education level, and poor glycemic control were associated with unvaccinated status. Considering the risk-benefits of influenza vaccination in patients with diabetes, physicians should make an effort to increase vaccination rates, especially in low vaccination rate groups.

Neurological complications associated with influenza in hospitalized children.

Influenza is a known respiratory and potential neurotropic virus. This study aimed to determine the prevalence and outcomes of influenza-related neurological complications among hospitalized children. All medical records of hospitalized children aged <18 years old diagnosed with influenza at a tertiary care hospital in Bangkok were retrospectively reviewed. Influenza infection was confirmed by rapid antigen or reverse transcription polymerase chain reaction tests. Neurological characteristics and clinical outcomes were analyzed using the Pediatric Cerebral Performance Category Scale. From 2013 to 2018, 397 hospitalized children with a median age of 3.7 years (interquartile range [IQR]: 1.6-6.9) were included. The prevalence of neurological complications, including seizure or acute encephalopathy, was 16.9% (95% confidence interval [CI]: 13.3-20.9). Influenza A and B were identified in 73.1% and 26.9% of the patients, respectively. Among 39 (58.2%) acute symptomatic seizure cases, 25 (37.3%) children had simple febrile seizures, 7 (10.4%) had repetitive seizures, and 7 (10.4%) had provoked seizures with pre-existing epilepsy. For 28 (41.8%) encephalopathy cases, the clinical courses were benign in 20 (29.9%) cases and severe in 8 (11.9%) cases. Ten (14.9%) children needed intensive care monitoring, and 62 (93.5%) fully recovered to their baselines at hospital discharge. Predisposing factors to the neurological complications included a history of febrile seizure (adjusted odds ratio [aOR]: 20.3; 95% CI: 6.6-63.0), pre-existing epilepsy (aOR: 3.6; 95% CI: 1.3-10.2), and a history of other neurological disorders (aOR: 3.5; 95% CI: 1.2-10.2). One fifth of hospitalized children with influenza had neurological complications with a favorable outcome. Children with pre-existing neurological conditions were at higher risk for developing neurological complications.

Burden of influenza hospitalization among high-risk groups in the United States

BackgroundSeasonal influenza poses a substantial clinical and economic burden in the United States and vulnerable populations, including the elderly and those with comorbidities, are at elevated risk for influenza-related medical complications.MethodsWe conducted a retrospective cohort study using the IQVIA PharMetrics® Plus claims database in two stages. In Stage 1, we identified patients with evidence of medically-attended influenza during influenza seasons from October 1, 2014 to May 31, 2018 (latest available data for Stage 1) and used a multivariable logistic regression model to identify patient characteristics that predicted 30-day influenza-related hospitalization. The findings from Stage 1 informed high-risk subgroups of interest for Stage 2, where we selected cohorts of influenza patients during influenza seasons from October 1, 2014 to March 1, 2019 and used 1:1 propensity score matching to patients without influenza with similar high-risk characteristics to compare influenza-attributable rates of all-cause hospital and emergency department (ED) visits during follow-up (30-day and in the index influenza season).ResultsIn Stage 1, more than 1.6 million influenza cases were identified, of which 18,509 (1.2%) had a hospitalization. Elderly age was associated with 9 times the odds of hospitalization (≥65 years vs. 5–17 years; OR = 9.4, 95% CI 8.8–10.1) and select comorbidities were associated with 2–3 times the odds of hospitalization. In Stage 2, elderly influenza patients with comorbidities had 3 to 7 times higher 30-day hospitalization rates compared to matched patients without influenza, including patients with congestive heart failure (41.0% vs.7.9%), chronic obstructive pulmonary disease (34.6% vs. 6.1%), coronary artery disease (22.8% vs. 3.8%), and late-stage chronic kidney disease (44.1% vs. 13.1%; all p < 0.05).ConclusionsThe risk of influenza-related complications is elevated in the elderly, especially those with certain underlying comorbidities, leading to excess healthcare resource utilization. Continued efforts, beyond currently available vaccines, are needed to reduce influenza burden in high-risk populations.

Burden of influenza in patients with cardiovascular disease who receive antiviral treatment for influenza

Aims Cardiovascular disease (CVD) increases the risk of complications from respiratory viruses, including influenza. Moreover, respiratory viruses may increase the risk of CV events. Antiviral medication may reduce healthcare resource utilization (HRU), but more data is needed in CVD populations to explore relationships between influenza antiviral treatment, CVD-related complications, HRU, and costs. Materials and methods This retrospective claims analysis examined data extracted from IBM MarketScan Commercial Claims and Encounters and Medicare Supplemental and Coordination of Benefits databases during three influenza seasons: 2016–2017, 2017–2018, or 2018–2019. Propensity score matching was used to compare HRU outcomes and costs among CVD patients treated with influenza antivirals and untreated patients. Results Across all influenza seasons, patients with CVD and influenza who received antiviral treatment had fewer all-cause emergency department (ED) visits (p < .01), respiratory-related HRU (p < .01), respiratory-related outpatient and ED visits (both p < .01), CVD-related HRU (p < .01), heart failure-related HRU visits (p < .01), and kidney failure-related HRU (p < .01) 180 days post-treatment fill date than CVD patients untreated for influenza. CVD patients treated with antivirals also had a lower mean number of all-cause inpatient, outpatient, and ED visits and days of stay (all p < .01) and fewer mean respiratory-related outpatient and ED visits (both p < .01). HRU patterns were generally consistent over time and across individual influenza seasons. Finally, treated CVD patients incurred lower all-cause outpatient costs 180 days post-treatment fill date (p < .05) than CVD patients untreated for influenza. Conclusion CVD patients who contract influenza and take antiviral medication have fewer short- and long-term influenza-related complications and less overall HRU compared with CVD patients who were not prescribed antiviral treatments. Antiviral treatment may be an important tool in reducing complications in CVD patients with influenza.

Clinical Pathway for Influenza in the Elderly: A comprehensive management protocol of Malaysia

Introduction: The clinical pathway (CP) is one of the most recommended tools for ensuring the best quality of care and has been proven to reduce the cost and time spent in hospital. The development of a CP for influenza is crucial, especially for the elderly, as they are vulnerable to influenza-related complications. The main aim of this study was to provide a comprehensive protocol for each component of influenza management among the elderly in Malaysia. Methods: An expert group meeting was conducted involving family medicine specialists, public health specialists, geriatricians, respiratory physicians and infectious disease physicians. The CP was designed following a 6-step protocol: 1) Selection of expert panel, 2) discussion and information gathering, 3) development of CP draft, 4) refinement of CP draft, 5) implementation of CP, and 6) finalisation of CP. The CP for influenza was designed based on service type and disease severity. Results: The panel described both outpatient and inpatient CPs for managing elderly patients with influenza. The outpatient CP covered mild and moderate influenza cases, while the inpatient CP addressed the management of moderate and severe influenza. The estimated length of hospital stay for moderate and severe influenza cases with pneumonia was 6 and 14 days, respectively. Conclusions: The CP for influenza supports existing treatment according to illness severity leveraged on current clinical practice guidelines and the best-care practices in primary and tertiary care settings. Continuous use of the CP is required to assess its effectiveness, thereby enabling optimisation of the healthcare process in influenza treatment.

Cost-Effectiveness of Extending the National Influenza Vaccination Program in South Korea: Does Vaccination of Older Adults Provide Health Benefits to the Entire Population?

The South Korean government has successfully improved influenza vaccination coverage for individuals aged 65 years or older as part of its National Immunization Program (NIP). Those aged 50–64 years without funded vaccination care have significantly lower vaccination rates and face a substantial risk of influenza-related complications. We use a dynamic epidemiological and economic model to investigate the cost-effectiveness of expanding the universal vaccine fund to include those aged 50–64. The epidemiological model is estimated using the susceptibility-infection-recovery model and influenza and influenza-like illness incidence rates, which were calculated by the National Health Insurance Service–National Sample Cohort from the 2008/09 to 2012/13 influenza seasons but excluding the 2009/10 season for pandemic influenza A (H1N1). The decision tree economic model is assessed from societal and healthcare sector perspectives. The proposed policy would eliminate 340,000 annual influenza cases and prevent 119 unnecessary deaths. From a societal perspective, the proposed policy would reduce costs by USD 68 million. From a healthcare perspective, the cost is USD 4318 per quality-adjusted life years. Within the study range, sensitivity analyses found consistent cost-effectiveness results. The influenza vaccine for adults aged 50–64 appears to be cost-saving or cost-effective and, thus, should be considered for the NIP.

Live Influenza Vaccine Provides Early Protection against Homologous and Heterologous Influenza and May Prevent Post-Influenza Pneumococcal Infections in Mice.

Influenza and S. pneumoniae infections are a significant cause of morbidity and mortality worldwide. Intranasal live influenza vaccine (LAIV) may prevent influenza-related bacterial complications. The objectives of the study are to estimate resistance against early influenza infection and post-influenza pneumococcal pneumonia after LAIV in mice. Mice were administered intranasally the monovalent LAIV A/17/Mallard Netherlands/00/95(H7N3), A/17/South Africa/2013/01(H1N1)pdm09 or trivalent LAIV 2017–2018 years of formulation containing A/17/New York/15/5364(H1N1)pdm09 vaccine strain. LAIV demonstrated early protection against homologous and heterologous infections with A/South Africa/3626/2013 (H1N1) pdm09 influenza virus on day six, following immunization. Following boost immunization, trivalent LAIV demonstrated a pronounced protective effect both in terms of lethality and pneumococcal lung infection when S. pneumoniae infection was performed three days after the onset of influenza infection. Conclusion: LAIV provides early protection against homologous and heterologous viral infections and has a protective effect against post-influenza pneumococcal infection. These data suggest that the intranasal administration of LAIV may be useful during the cycle of circulation not only of influenza viruses, but also of other causative agents of acute respiratory infections.

Knowledge attitudes and practices toward seasonal influenza vaccine among pregnant women during the 2018/2019 influenza season in Tunisia.

The uptake and acceptance of the influenza vaccine (IV) among pregnant women remain unknown in Tunisia despite the increased influenza-related complications and death. The present study aimed to assess the IV uptake and acceptability and to describe related knowledge and attitudes among pregnant women in Tunisia. A cross-sectional study was conducted in 84 Tunisian healthcare facilities over a period of three months (from March to May 2019). All pregnant women aged ≥18 years who sought antenatal care in related health structures were included in this study based on a multistage self-weighted sampling. We measured knowledge and attitudes towards the IV and assessed factors related to willingness for its uptake. The questionnaire was completed by 1157 pregnant women. More than half of the participants (60.2%; 95% confidence interval [CI] [57.3%-63.0%]) reported awareness about the IV. Among included PW, only 4.6%; 95% CI [3.5%-6.1%] received it during their current pregnancy. However, (36.8%; 95% CI [34.0%-39.6%]) declared their willingness to receive the vaccine in the next pregnancy. Recommendation by healthcare providers, identified to be the most trustful source of information, was the main reason for acceptance. However, the intention to accept the IV by pregnant women was significantly associated with such recommendation and perceived safety and effectiveness of this vaccine. Antenatal care visits are a precious opportunity that should not be missed by health care providers and especially gynecologists to promote the IV uptake by pregnant women in Tunisia.

Influenza vaccination in patients with heart failure: A protocol for meta-analysis of randomized controlled trials.

Background:Heart failure is a major public health problem. Although there have been significant advances in the management of heart failure, the mortality and morbidity in heart failure patients remain high. Heart failure patients are susceptible to influenza-related complications including acute heart failure exacerbations and secondary infections such as pneumonia, both of which lead to significant morbidity and mortality. An earlier meta-analysis of observational cohort studies reported that influenza vaccination was associated with reduced risk of mortality in heart failure patients. Although there are no published randomized controlled trials (RCTs) on the effect of influenza vaccination on clinical outcomes in heart failure patients, there are several on-going RCTs examining the effect in these patients. We aim to conduct a meta-analysis of RCTs to assess the efficacy and safety of influenza vaccination in heart failure patients.Methods:This meta-analysis will include RCTs examining the effect of influenza vaccination in heart failure patients. Information of studies will be collected from electronic databases. The primary outcome of interest will be cardiovascular death. The secondary outcomes of interest will be all-cause death, nonfatal myocardial infarction, nonfatal stroke, hospitalization for heart failure, and hospitalization for any cause.Discussion:This meta-analysis will evaluate the efficacy and safety of influenza vaccination in heart failure patients, providing evidence to the use of influenza vaccine in these patients.Systematic review registration:INPLASY202210115.