An analysis of the demand for influenza vaccination among the elderly in Japan

PURPOSE: This paper will discuss an analysis of the demand for vaccination for the elderly as a high-risk group. Influence of the governmental endorsement and/or subsidy on these demand is, then, evaluated from the estimation results. METHODS: Original data were obtained from two surveys conducted by the author for the elderly living with and without descendents. Information was collected about the elderly themselves, the household, experience of influenza and immunization in the last season, and the hypothetical questionnaire about immunization was answered by each respondent to be applied for Conjoint Analysis. Three estimations are performed for the actual behavior, Conjoint Analysis and the joint estimation of these two methods. RESULTS: Experience of influenza and immunization in the last season, proved to be two of the most important determinants. Among the others estimated parameters, cost of immunization, the number of immunization to complete for effectiveness, availability of the immunization at night or on a weekend, and the governmental endorsement greatly affected the immunization demand. Moreover, the superiority of the statistical properties of the joint estimation was confirmed. CONCLUSIONS: The estimation results imply that about 8.9 million elderly people would demand vaccination if there was no cost and there was a governmental endorsement. This would be reduced to be 3.2 million if the cost was 6,000 yen (about 50 dollars) and there was no governmental endorsement. Governmental endorsement alone would increase the number by 2.0 million. The change from no cost to only 500 yen (about 4 dollars) would depress the demand by 1.6 million.     

孕妇流感疫苗接种相关研究进展

流感是由流感病毒引起的急性呼吸道传染病, 妊娠期间因生理和免疫功能的变化, 孕妇罹患流感及发生相关并发症的风险较高。接种流感疫苗是预防流感的有效手段。WHO和许多国家均将孕妇列为流感疫苗接种的优先推荐人群, 但目前我国孕妇流感疫苗接种率偏低, 且部分产品使用说明将孕妇列为接种禁忌人群, 推动孕妇流感疫苗接种工作仍存在诸多挑战。本文就近年来国内外流感对孕妇及其胎儿的影响以及孕妇接种流感疫苗研究进展进行综述, 并针对目前孕妇流感疫苗接种的现状, 提出促进孕妇接种流感疫苗的策略并进行探讨, 以期为我国相关工作的开展和政策制定提供参考。     

The demand for health: An empirical reformulation of the Grossman model

Previous tests of Grossman's model of the demand for health have been based on Grossman's own empirical formulation. This paper argues that this formulation fails to capture the dynamic character of the model. It proposes an alternative formulation, which appears to be more consistent with Grossman's theoretical model and which may also explain the apparent rejections of the model by the data in the author's earlier empirical work. The paper also presents some empirical results obtained using the new formulation, which are, on the whole, consistent with the predictions of Grossman's theoretical model.     

Target groups for influenza vaccination

PURPOSE: To assess target groups for influenza vaccination. METHODS: The target groups for influenza vaccination specified in the recommendations of the US Advisory Committee on Immunization Practices (ACIP) were summarized and compared between 1997 and 2006. RESULTS: Principal changes after the 1997's recommendation are as follows: 1) all children aged 6-59 months became included into the high risk group for active vaccination; 2) recommendation for vaccination timing of pregnant women was extended from those at the second trimester or after to all women who are pregnant during the influenza season; 3) persons with neuro- or muscular-disorders and therefore prone to development of respiratory systems or aspiration pneumonia became included into the high risk group; 4) a category with increased risk to visit a clinic, hospital or emergency department due to influenza-related symptoms was newly established, covering children aged 24-59 months and persons aged 50-64 years; 5) healthy household contacts and caregivers of children aged 0-59 months were included into the group who can transmit influenza to persons in the high risk group; 6) people likely to transmit influenza to persons in the high risk group were classified into 3 categories (health-care providers, household contacts and caregivers, and those in close contact with children aged 0-59 months). CONCLUSION: The ACIP has gradually expanded the target populations for routine influenza vaccination. The most notable change during past 10 years seems to be the recommendation for inclusion of all children aged 6-59 months and people in close contact with babies for active vaccination.     

An economic analysis of annual influenza vaccination of children

We used a Monte Carlo mathematical model to calculate the net economic returns (cost-benefit analysis) from annually vaccinating children against influenza. The model included cohorts of 1000 children in three different age groups (6-23 months, 6-59 months, and 5-14 years), with different proportions of children with high risk conditions (100, 10, and 0%). Vaccinating cohorts of 100% high risk children in all three age groups produced median net savings, regardless of cost of vaccination examined (US dollar 30-60/dose administered). Median threshold vaccination costs for cohorts containing 10% high risk children were US dollar 48, 46, and 45 per dose administered for age groups 6-23 months, 6-59 months, and 5-14 years, respectively (US dollar/dose administered below these thresholds generate net savings). For all cohorts, for the range of cost per dose administered examined, the 5th percentiles were net costs. The probability of death, though rare, was the most influential distribution in the model. The number of high-risk children that receive influenza vaccine should be maximized to achieve improved health outcomes as well as cost savings.     

深圳市学龄儿童接种流感疫苗对缺课预防效果的实证研究

目的 评估深圳市采用入校接种方式以及学龄儿童流感疫苗接种率高低对缺课的影响。方法 以深圳市小学学龄儿童为研究对象,利用2017年12月至2020年6月深圳市286所小学缺课数据以及学龄儿童流感疫苗接种政策实施后深圳市9个区疫苗接种率和组织方式（入校接种与非入校接种）数据,以缺课人数作为被解释变量,分别以组织方式和区接种率作为分组变量,构建双重差分模型,采用泊松回归进行分析,并对回归结果进行稳健性检验。结果 相比于非入校接种和低接种率,入校接种和高接种率可有效降低缺课的发生风险,对缺课的预防效果分别为32.6%（95%CI： 17.0%~45.3%,P<0.01）和53.0%（95%CI：42.1%~61.8%,P<0.01）。结论 深圳市实施学龄儿童流感疫苗免费接种政策并优先采用入校接种的方式,可有效降低学生缺课的发生风险。     

An empirical analysis of the demand for physician services across the European Union

This paper presents parameter estimates for physician service equations using the "European Community Household Panel" for 12 countries covering the period 1994-1996. The focus is on two specific points: (1) the identification of behavioural similarities and differences in the demand for health services across the 12 countries; (2) the variability in demand for health services represented through a joint model for all countries. We found that there are significant differences among countries, although there are also similarities in the effect of variables such as health stock, labour situation or family structure. An important fraction of the variability in the demand for health services across countries could be explained by differences in age, income and the role of general practitioners as gatekeepers in the public health system. We found some evidence of induced demand in the decision to visit a specialist and in the number of such visits.     

商业健康保险需求理论与实证研究综述

系统归纳和总结了国外商业健康保险需求的基本经济学理论和最新发展动态,同时对国内近年来在商业健康保险需求方面的实证研究进行了综述,将商业健康保险需求的影响因素主要归结为收入水平、健康状况、教育水平和强制性社会保险等方面。分析了我国商业健康保险需求不足的原因,并提出如下解决措施：提升公众健康保险的需求意识;准确定位社会医疗保险和商业健康保险之间的关系;保险经营者要不断改进和完善产品与服务,以满足人们多层次、多样化的健康保障需求。     

Different influenza vaccine formulations and adjuvants for childhood influenza vaccination

Pediatric influenza is a very common disease: attack rates range from 23% to 48% during interpandemic years and are significantly higher during pandemics. Influenza-related complications seem to be more common in children at risk because of an underlying chronic severe disease, but recently collected data clearly demonstrate that otherwise healthy children can also suffer from severe influenza and that the annual number of deaths is no different between the two groups. The aim of this review is to discuss the characteristics of all influenza vaccines in order to evaluate the real likelihood of prevention, as well as the safety and tolerability of the different formulations and adjuvants. The data indicate that further studies collecting efficacy and effectiveness data and evaluating the immunogenicity and safety of the different formulations and adjuvants should lead to the identification of more ideal influenza vaccines that could be used with significant advantage in the entire pediatric population.     

Organising services for influenza vaccination for older people

OBJECTIVES: To follow up a trial of home-administered influenza vaccination of older people to explore reasons for their immunisation behaviour, including their views on the organisation of services. METHODS: Follow-up of original trial using analysis of records of 1865 older people and semi-structured interviews of 25 older people. RESULTS: A once-off home visit does not appear to result in sustained changes in immunisation behaviour. Older people's behaviour appears to be largely explained by their beliefs about immunisation; the organisation of services may exert only small effects. Older people can be characterised as belonging to one of four groups in their orientation towards influenza vaccination: the 'faithful', who are keen to have vaccination; the 'converts', who have been persuaded of the benefits of vaccination and are likely to self-initiate appointments for vaccination; the 'easy-going', who require prompting for vaccination; and the 'sceptics', who perceive influenza vaccination to be ineffective or to be irrelevant for them because of their perceived inherent resistance to influenza. The last group sees vaccination as a form of interference and may be resistant to home visits to administer the vaccine. CONCLUSIONS: Targets for immunising older people require more debate because of the delicate balance between achieving herd immunity and preserving autonomy and choice for older people.     

Determinants of influenza vaccination timing

New guidelines recommend different influenza vaccination timing for different subpopulations due to the limited availability of flu shots (FS). This study's objectives are to develop a theoretical model to demonstrate why some individuals choose to receive an early FS while others choose a late FS and to empirically explore the determinants of vaccination timing. Empirical results generally supported the theoretical results. Individuals vary their FS timing in response to variations in perceived risks, chronic condition levels reflecting their risk of influenza infection, and opportunity costs, measured by the presence of medical care other than an FS.     

The effect of smoking on influenza, influenza vaccination efficacy and on the antibody response to influenza vaccination

We examined the relation between cigarette smoking and (1) the occurrence of influenza, (2) the efficacy of influenza vaccination and (3) the antibody response to influenza vaccination in fifteen family practices in South-Limburg, the Netherlands, during the influenza season 1991 1992. Data were used from a randomized double-blind placebo-controlled trial into the efficacy of influenza vaccination in which smoking status was measured 10 weeks after the start of the trial. A total of 1838 subjects aged 60 years or older, of whom 1531 subjects (321 smokers, 1152 non-smokers and 58 cigar/pipe smokers) who returned the smoking questionnaire and were not previously vaccinated, were used in the analyses. The main outcome measures were serological influenza (fourfold increase of antibody titre between 3 weeks and 5 months after vaccination); clinical influenza as determined by criteria of the Dutch Sentinel Stations from self reported symptoms in postal questionnaires 10 weeks and 5 months after vaccination; increases after vaccination and decreases after 5 months in logarithmic titres of antibody against the vaccine strains. No relation between smoking and either serological or clinical influenza was found, although the risk for serological influenza was slightly (not significantly) elevated in smokers compared to non-smokers. A statistical interaction was found between smoking and vaccination when serological influenza was the outcome measure indicating that the efficacy of vaccination was greater in smokers than in non-smokers (comparison of model with and without interaction; likelihood ratio test, p < 0.0001). This finding is supported by a greater titre rise 3 weeks after vaccination for two out of four strains, but not by the antibody response after vaccination in previous studies on influenza and other infectious diseases. Also, this possible difference of immunogenicity is not reflected in a better protection for clinical influenza. The rise in antibody titre 3 weeks after vaccination was higher in smokers for A/Singapore/6/86 and B/Beijing/11/87, but not for the other two strains. Decline in titres after 5 months was similar for smokers and non-smokers. We conclude that smoking has no clinical or preventive significance for risk of influenza in the elderly.     

Effectiveness and cost-effectiveness of influenza vaccination for elderly people

For elderly people who have low incidence of influenza, calculation of credible vaccine effectiveness (VE) sometimes becomes difficult. Currently, VE for elderly people is insufficient to ascertain the precise efficacy specifically. Cost-effectiveness of influenza vaccination of elderly people is discussed widely in terms of topics and areas. This report describes research results demonstrating influenza vaccination effectiveness among elderly people based on recent findings. Newly available influenza vaccination for elderly people appears to be cost-effective compared with that of trivalent inactiveted influenza vaccine. Overall, for all influenza virus types, it remains unclear whether influenza vaccination shows high VE. A decreasing effect of repeated vaccination was confirmed partially by test negative design and a serological study of cohorts. However, some studies have found no such decreasing effect. Measurement of VE and subsequent analysis of the cost-effectiveness of influenza vaccination for elderly people requires long-term monitoring using serological studies and test negative design.     

Approaches to improved influenza vaccination

Inactivated influenza vaccine (Ivac) has had an important impact on reducing attack rates of influenza and reducing the severity of illness amongst the vaccinees who still acquire infection. Ivac is most efficacious amongst young, otherwise healthy subjects and least effective against elderly at high risk. This is in part because Ivac does not appear to significantly reduce infection rates and in part because response rate and final antibody titer are lower in the elderly. Therefore Ivac does not eliminate disease in the elderly who are prone to complications when any virus replication occurs. Simultaneous administration of intra-nasal live attenuated influenza vaccine (Livac) and Ivac reduces the infection rate and thus illness rate amongst high-risk elderly. Presumably this is because of the ability of Livac to stimulate secretory antibody which neutralizes virus at the mucosal surface. Other approaches are examining the benefit of baculovirus recombinant vaccine or adjuvanted Ivac to determine if the higher serum antibody these vaccines produce compared to Ivac, will diffuse onto the mucosal surfaces and in a similar fashion, neutralize virus at that site.     

Under-explored assumptions in influenza vaccination models: Implications for the universal vaccination of children

The aim of this study was to explore several important (but uncertain) assumptions in influenza models which affect the estimated benefits of vaccination programs. We combined consideration of these factors with the seasonal variability of influenza transmissibility to gain a better understanding of how they may influence influenza control efforts. As our case study, we considered the potential impact of universal seasonal childhood vaccination in Australia using a simplified age-stratified Susceptible Exposed Infectious Recovered (SEIR) model to simulate influenza epidemics and the impact of vaccination. We found that the choice of vaccine efficacy model was influential in determining the impact of vaccination. This choice interacted with other model assumption such as those around the infectiousness of asymptomatic cases and the match of the vaccine to the circulating strains. The methodological approach used to estimate influenza hospitalisations was also highly influential. Our study highlights the role that key modelling assumptions play when estimating the impact of vaccination against influenza.