Individual background factors associated with vaccination for seasonal influenza in Japanese schoolchildren

Published online: September 12, 2017There is little evidence about how individual background factors affect seasonal influenza vaccination of children. At the end of the 2014/2015 influenza season, a cross-sectional questionnaire survey of all elementary schoolchildren in 29 schools in Matsumoto City, Japan, was conducted to obtain information about vaccine uptake activity and individual background factors. Of the 10,524 subjects who responded, 5063 (48.1%) had been vaccinated. Grade in school, underlying disease, number of siblings, and diagnosis with and vaccination for influenza during the previous influenza season differed significantly in vaccinated and unvaccinated groups. Multivariate logistic regression showed that underlying disease and vaccination during the previous influenza season was associated with a higher rate of vaccination, whereas higher grade in school and having ≥3 siblings was associated with a lower rate of vaccination. The findings may be useful to promote a vaccination policy recommending financial support to households with many children or to encourage higher uptake of vaccination in higher grade children.ArticleJournal of Infection and Chemotherapy. DOI: 10.1016/j.jiac.2017.08.015 (2017)journal articl

Effects of personality on overtime work: a cross-sectional pilot study among Japanese white-collar workers

BACKGROUND: As detailed associations between personality and long work hours are unclear, we assessed associations between personality dimensions and overtime work among Japanese white-collar workers. / METHODS: From records of hours worked over 12 months by 267 office workers in an organization within the service industry, average overtime work hours per month and occurrence of excessive overtime was determined for each worker. Excessive overtime was defined as >??45 overtime work hours per month for at least one month. Responses to a questionnaire assessing socio-demographic and workplace-related factors and the Big Five personality test were analyzed. Associations between personality factors and overtime work were assessed by multivariate logistic regression analysis. / RESULTS: Low Extraversion was associated with excessive overtime work (OR 2.02, 95%CI 1.02?-?4.02, P?=??0.04). / CONCLUSIONS: It is suggested that workers with low Extraversion can't share work when busy to avoid excessive overtime. Personality factors should be considered in studies evaluating work time. Moreover, strengthening communication among workers with low Extraversion may reduce excessive overtime work and associated health problems.ArticleBMC RESEARCH NOTES. 7:180 (2014)journal articl

Does change of residence affect pollinosis? A study of Japanese university students

The effects of change of residence on pollinosis symptoms remain unclear. We investigated the effects of geographical change of residence on pollinosis symptoms among university freshmen. All freshmen (n = 2142) entering Shinshu University in 2011 completed self-administered questionnaires. Associations between history of pollinosis and environmental factors were assessed. Subjects were classified into three groups according to pollen count at previous residences (stationary, low pollen, and high pollen). Pollinosis both before and after relocation were compared among and within the groups. Of the 1558 subjects, 540 (34.7%) developed pollinosis before and 483 (31.0%) after entering university. The rates of pre- and post-university entrance pollinosis were 40.0 and 32.5% in the high pollen group (P < 0.001) but were similar in the other two groups. Pollinosis symptoms decreased among students that moved from high to low pollen areas, indicating that pollinosis was affected by geographic environmental factors.ArticleINTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH. 23(5):380-391 (2013)journal articl

Role of household factors in parental attitudes to pandemic influenza-related school closure in Japan: a cross-sectional study

BACKGROUND: To investigate how household background factors affect parental behavior during pandemic influenza-related school closures, we determined associations between such factors and three parental attitudes: "caring for the child," "taking leave from work," and "permitting out-of-home activities." METHODS: A hypothetical pandemic influenza situation was presented and a questionnaire survey among households of 2146 schoolchildren from 6 schools was conducted. Odds ratios of background factors were estimated using univariate and multivariate logistic regression models. RESULTS: Responses pertaining to 1510 children indicated that junior high school (OR = 0.11), both parents working (OR = 0.03), and family including grandparent(s) or other relatives (OR = 7.50) were factors associated with "caring for the child," and elementary school (OR = 2.28), special education school (OR = 3.18), and both parents working (OR = 5.74) were associated with "taking leave from work." Having an older sibling (OR = 0.74) and awareness of the technical term for school closure (OR = 0.73) were factors associated with "permitting out-of-home activities." CONCLUSION: Not only work status but also other household factors may be associated with parental behaviors during pandemic influenza-related school closures.ArticleBMC Public Health. 14:1089 (2014)journal articl

Fine-scale family structure shapes influenza transmission risk in households: Insights from primary schools in Matsumoto city, 2014/15.

Households are important settings for the transmission of seasonal influenza. Previous studies found that the per-person risk of within-household transmission decreases with household size. However, more detailed heterogeneities driven by household composition and contact patterns have not been studied. We employed a mathematical model that accounts for infections both from outside and within the household. The model was applied to citywide primary school seasonal influenza surveillance and household surveys from 10,486 students during the 2014/15 season in Matsumoto city, Japan. We compared a range of models to estimate the structure of household transmission and found that familial relationship and household composition strongly influenced the transmission patterns of seasonal influenza in households. Children had a substantially high risk of infection from outside the household (up to 20%) compared with adults (1-3%). Intense transmission was observed within-generation (between children/parents/grandparents) and also between mother and child, with transmission risks typically ranging from 5-20% depending on the transmission route and household composition. Children were identified as the largest source of secondary transmission, with family structure influencing infection risk

Evaluation of factors affecting variations in influenza A/H1N1 history in university students, Japan

Although the natural history of H1N1 has been found to vary among patients, little is known about the factors that affect these variations. Infected patients with an extended infection history may shed virus longer and spread infection. To further clarify these variations, we evaluated the natural history of H1N1 infection in 324 university students using a descriptive epidemiological method and analyzed factors affecting the natural history of infection. The median times from infection to fever development and from fever development to cure were 2 days (range 0?8 days) and 5 days (range 1?12 days), respectively, and the median time not attending classes was 5 days (range, 1?13 days). Variations in H1N1 natural history were associated with both environmental and individual factors, including route of infection, grade, gender, epidemic period, respiratory and gastrointestinal symptoms and headache. Steps affecting these factors may help control variations in H1N1 natural history and may enhance infection control measures.ArticleJOURNAL OF INFECTION AND CHEMOTHERAPY. 19(4):665-672 (2013)journal articl

Evaluation of the spread of pandemic influenza A/H1N1 2009 among Japanese university students

online first / Published online: 4 July 2014The pandemic influenza A/H1N1 2009 virus is commonly known to affect younger individuals. Several epidemiological studies have clarified the epidemic features of university students in Japan. In this study, we reviewed these studies in Japan in comparison with reports from other countries. The average cumulative incidence rate among university students was 9.6 %, with the major symptoms being cough, sore throat, and rhinorrhea. These epidemiological features were similar between Japan and other countries. Attitudes and behaviors toward pandemic influenza control measures were different before and improved during and after the epidemic. These features were also similar to those in other countries. On the other hand, the epidemic spread through club activities or social events, and transmission was attenuated after temporary closure of such groups in Japan. This transmission pattern was inconsistent among countries, which may have been due to differences in lifestyle and cultural habits. Based on these results, infection control measures of pandemic influenza for university organizations in Japan should be considered.ArticleEnvironmental Health and Preventive Medicine. 19(5):315-321 (2014)journal articl

How the H1N1 influenza epidemic spread among university students in Japan: Experience from Shinshu University

Background: A worldwide outbreak of influenza A/H1N1 occurred in 2009. Little information is available regarding how the epidemic spread among young people, who composed the majority of individuals infected with this virus. We assessed the route of transmission of H1N1 among university students at Shinshu University, Japan. Methods: A total of 11,424 students were monitored between August 2009 and March 2010, and those who were diagnosed with confirmed, probable, or suspected H1N1 at a hospital or clinic were registered based on self-report to the university. Data including date of onset and suspected infection route were collected from the affected patients. Results: Of the 11,424 students, 1,016 (8.9%) were infected with H1N1. In most infected students, the suspected transmission route was associated with club activity, followed by close contact with friends and through lectures or laboratory work. After suspension of activity by clubs with more than 2 infected members, the number of infected individuals decreased. Conclusion: H1N1 influenza spread in the university through specific routes, including club activity, close contact with friends, and lectures or laboratory work. During future outbreaks of influenza, interventions to reduce transmission through these routes may be effective infection control strategies in university students.ArticleAMERICAN JOURNAL OF INFECTION CONTROL. 40(3):218-220 (2012)journal articl

Within and between classroom transmission patterns of seasonal influenza among primary school students in Matsumoto city, Japan

Schools play a central role in the transmission of many respiratory infections. Heterogeneous social contact patterns associated with the social structures of schools (i.e., classes/grades) are likely to influence the within-school transmission dynamics, but data-driven evidence on fine-scale transmission patterns between students has been limited. Using a mathematical model, we analyzed a large-scale dataset of seasonal influenza outbreaks in Matsumoto city, Japan, to infer social interactions within and between classes/grades from observed transmission patterns. While the relative contribution of within-class and within-grade transmissions to the reproduction number varied with the number of classes per grade, the overall within-school reproduction number, which determines the initial growth of cases and the risk of sustained transmission, was only minimally associated with class sizes and the number of classes per grade. This finding suggests that interventions that change the size and number of classes, e.g., splitting classes and staggered attendance, may have a limited effect on the control of school outbreaks. We also found that vaccination and mask-wearing of students were associated with reduced susceptibility (vaccination and mask-wearing) and infectiousness (mask-wearing), and hand washing was associated with increased susceptibility. Our results show how analysis of fine-grained transmission patterns between students can improve understanding of within-school disease dynamics and provide insights into the relative impact of different approaches to outbreak control