Lifestyle,socioeconomic characteristics,and medical history of elderly persons who receive seasonal influenza vaccination in a tax-supported healthcare system

BackgroundObservational studies on effectiveness of influenza vaccination in the elderly are thought to be biased by healthier lifestyles and higher socioeconomic status among vaccinated vs. unvaccinated persons. We examined this hypothesis in a uniform tax-supported health care system with free-of-charge influenza vaccination to the elderly.MethodsWe conducted a cross-sectional study among Danes aged 65–79 years participating in a survey. We compared elderly persons with and without a recent (within six months) influenza vaccination in terms of (i) lifestyle and socioeconomic characteristics obtained from the survey and (ii) health factors including medical history provided by Danish registries. We compared the prevalence of study variables among vaccinated and unvaccinated persons using age- and sex-adjusted prevalence ratios (aPRs) with 95% confidence intervals (CIs).ResultsAmong the 4237 elderly persons completing the survey, 1718 (41%) had received an influenza vaccination. Vaccinated persons had more comorbidity than unvaccinated persons (aPR for high comorbidity level: 1.51 95% CI 1.24–1.84), were less likely to never have smoked (aPR: 0.88, 95% CI 0.80–0.97), and had a higher prevalence of physical inactivity (aPR: 1.08, 95% CI 1.03–1.13). Levels of education and income were similar in the two groups. Vaccinated persons had a higher prevalence of major physical limitations (aPR: 1.40, 95% CI 1.17–1.66) and need for assistance with activities of daily living (aPR: 1.29, 95% CI 1.13–1.47).ConclusionElderly influenza vaccinated persons were not healthier in terms of lifestyle and burden of disease, did not have a higher socioeconomic status, and were more frail than unvaccinated persons.     

Prevalence and predictors of influenza vaccination among frail, community-living elderly patients: an international observational study

The annual winter outbreak of influenza is one of the major cause of morbidity and mortality among frail elderly people. The aim of the present study was to identify prevalence and predictors of influenza vaccination in a large European population of frail and old people living in community. This was an observational study conducted in 11 European countries. We enrolled 3878 people 65 years and older already receiving home care services within the urban areas. All participants were assessed with the Minimum Data Set-Home Care (MDS-HC) instrument containing over 300 items, including socio-demographic, physical and cognitive characteristics of patients as well as medical diagnoses and medications received. A single question about the influenza vaccination status was used. The rate of influenza vaccination was around 59% of the studied sample. Significant geographical variations were evident in the prevalence of vaccination ranging from 31% of Prague (Czech Republic) to 88% of Rotterdam (The Netherlands). Overall, persons living alone were less likely to receive influenza vaccine as compared with those living with an informal caregiver (OR, 0.78; 95% CI 0.67-0.90). Similarly, cognitive impairment and presence of economic problems were associated with a lower likelihood of being vaccinated (OR: 0.69, 95% CI 0.59-0.80 and OR, 0.58; 95% CI 0.45-0.74, respectively). On the other hand, old age and comorbidity were associated with an higher probability of being vaccinated. In conclusion, more than 40% of subjects in this sample of home care patients in Europe did not receive influenza vaccination. Recommendations for influenza vaccination have not been adequately implemented.     

Economic evaluation of vaccination against influenza in the elderly: an experience from a population-based influenza vaccination program in Taiwan

Due to viral strains, influenza season, and consultations and admission rates varying from country to country, the continued economic evaluation of influenza vaccination for the elderly people aged 65 years and above is paramount, particularly in areas with dense population. Efficacy and cost-effective analysis of influenza vaccination in reducing all-cause mortality and hospitalization was therefore elucidated based on a prospective and population-based study targeted to 226,997 elderly people aged 65 years and above residing in Taipei county, Taiwan between 1 October 2000 and 31 March 2001. Vaccination against influenza for the elderly persons can lead to a 29% (95% CI: 23-35%) significant reduction of all-cause deaths. Approximately, 20% (95% CI: 9-30%) significant reduction in hospitalization was observed for average-risk group but 4% (95% CI: -4-11%) non-significant reduction for high-risk group. Community-based influenza vaccination program for elderly people aged 65 years and above was demonstrated to be effective in reducing mortality in all elderly people but not significantly in reducing hospitalization. Universal vaccination program for the elderly people seems cost-effective in averting death or gaining life years.     

Duration of influenza vaccine effectiveness in the elderly in Japan: A retrospective cohort study using large-scale population-based registry data

BackgroundThe immune response to influenza vaccination in the elderly is likely to be lower than that in young adults. Clinical protection may not persist year-round in the elderly. However, the effectiveness of influenza vaccine in the elderly has not been adequately studied, especially in terms of the duration of effectiveness.MethodsWe used a linked database of healthcare administrative claims data and vaccination records maintained by the municipality of a city in Kanto region of Japan. We studied individuals who were aged 65 years or older at baseline and were followed up between April 1, 2014 to March 31, 2020. The duration of influenza vaccine effectiveness by age category was analyzed using a time-dependent piecewise Cox proportional hazard model with time-dependent vaccine status, prior season vaccination and covariates confirmed in the baseline period (age, sex, cancer, diabetes, chronic obstructive pulmonary diseases, asthma, chronic kidney diseases, and cardiovascular diseases).ResultsWe identified an analysis population of 83,146 individuals, of which 7,401 (8.9%) had experienced influenza and 270 (0.32%) underwent influenza-related hospitalization. Individuals who were vaccinated during the first season (n = 47,338) were older than non-vaccinated individuals (n = 35,808) (average age, 75.8 vs. 74.1 years, respectively). The multivariable analysis showed a lower incidence of influenza in vaccinated individuals (hazard ratio [HR], 0.47; 95% confidence interval [CI], 0.43–0.51; P < 0.001), while the incidence of hospitalization for influenza did not differ significantly by vaccination status (HR, 0.79; 95% CI, 0.53–1.18; P = 0.249). Protective effectiveness against incidence was maintained for 4 or 5 months after vaccination in those aged 65–69 and 80-years, 5 months in 70–79 years.ConclusionsOur study identified moderate vaccine effectiveness in preventing the incidence of influenza in the Japanese elderly. Vaccine effectiveness showed a trend of gradual attenuation. Clinicians should suspect influenza infection even in those vaccinated, especially in elderly individuals who had received vaccination more than 4 or 5 months previously.     

Effectiveness of repeated influenza vaccination among the elderly population with high annual vaccine uptake rates during the three consecutive A/H3N2 epidemics

BackgroundAnnually, about 80% of the Korean elderly aged ≥65 years receive influenza vaccination. Repeated annual vaccination has been suggested as an important factor of poor influenza vaccine effectiveness (VE), though reported conflicting results.MethodsDuring the consecutive A/H3N2-dominant influenza seasons between 2012 and 2015, we comparatively evaluated the VE (repeated vs. current season only) against laboratory-confirmed influenza, pneumonia and hospitalization in the elderly aged ≥65 years with influenza-like illness (ILI). Clinical and demographic data were collected prospectively, and vaccination status of prior and current seasons was verified using the immunization registry data of Korean Centers for Disease Control and Prevention.ResultsDuring the first A/H3N2-dominant season in 2012–2013, influenza vaccine showed statistically significant effectiveness against influenza A infection only and when vaccinated in the current season only (VE 53%, 95% CI 15–77). In the latter two seasons (2013–2015 years), the adjusted VE for influenza A was indistinguishable between repeated vaccination and vaccination in the current season only.ConclusionDuring consecutive influenza A/H3N2 epidemics, poor influenza vaccine effectiveness may be more pronounced among the elderly population with a high annual vaccine uptake rate.     

Longitudinal,population-based cohort study of prenatal influenza vaccination and influenza infection in childhood

BackgroundInfluenza vaccination is recommended to protect mothers and their infants from influenza infection. Few studies have evaluated the health impacts of in utero exposure to influenza vaccine among children more than six months of age.MethodsWe used probabilistically linked administrative health records to establish a mother–child cohort to evaluate the risk of influenza and acute respiratory infections associated with maternal influenza vaccination. Outcomes were laboratory-confirmed influenza (LCI) and hospitalization for influenza or acute respiratory infection (ARI). Adjusted hazard ratios (aHRs) accounted for child’s Aboriginal status and were weighted by the inverse-probability of treatment.Results14,396 (11.5%) children were born to vaccinated mothers. Maternally vaccinated infants aged < 6 months had lower risk of LCI (aHR: 0.33; 95% CI: 0.13, 0.85), influenza-associated hospitalization (aHR: 0.39; 95% CI: 0.16, 0.94) and ARI-associated hospitalization (aHR: 0.85; 95% CI: 0.77, 0.94) compared to maternally unvaccinated infants. With the exception of an increased risk of LCI among children aged 6 months to < 2 years old following first trimester vaccination (aHR: 2.28; 95% CI: 1.41, 3.69), there were no other differences in the risk of LCI, influenza-associated hospitalization or ARI-associated hospitalization among children aged > 6 months.ConclusionStudy results show that maternal influenza vaccination is effective in preventing influenza in the first six months and had no impact on respiratory infections after two years of age.     

In a prospective observational study, influenza vaccination prevented hospitalization among older home care patients

OBJECTIVE: The aim of the study is (1) to describe the prevalence of vaccination against influenza in older home care patients and (2) to investigate the protective effect of influenza vaccination for hospitalization events. STUDY DESIGN AND SETTING: This is an observational study conducted in four large cohorts of elderly patients in home care during the 1998-1999, 1999-2000, 2000-2001, and 2001-2002 influenza seasons. We analyzed data from the Italian Silver Network Home Care project. A total of 2,201 patients were enrolled in the present study. The main outcome measures were prevalence of vaccination against influenza and the rate of hospitalization according to vaccination status and influenza season. RESULTS: The rate of influenza vaccination was around 48% of the studied sample. During the follow-up including the peak of influenza and the total influenza season, 412 subjects (40%) were hospitalized among vaccinated compared to 610 subjects (59%) among not vaccinated (P<0.001). After adjusting for age, gender, location of home care program, and all the variables significantly different between vaccinated and not-vaccinated subjects, vaccinated subjects were less likely to be hospitalized compared to not-vaccinated subjects (OR, 0.73; 95% CI 0.60-0.90). CONCLUSIONS: Vaccination against influenza has an important prognostic implication for frail geriatric patients living in the community.     

Socioeconomic determinants of influenza vaccination among older adults in Italy

ObjectivesSeasonal influenza represents a major threat to public health but vaccination campaigns are strongly recommended to reduce the risks of serious complications and mortality among community-dwelling elderly persons. We investigated on potential social predictors of influenza vaccination among older adults in Italy.MethodsData analysis was based on the national survey “Health and use of health care,” which was carried out in 2004/2005 and reached a sample of 25,183 elderly persons. After initial univariate and bivariate statistics, we used multivariate logistic regression to evaluate potential independent predictors of influenza immunization.Results62.6% of the recruited subjects declared to be vaccinated against influenza. At bivariate analysis, significative differences in immunization rates arose by each socioeconomic variable investigated. Logistic regressions confirmed that individuals in lower social classes have higher chances of being vaccinated. Moreover, older age and chronic disease were associated with higher likelihood of immunization. Conversely, reporting good health predicted a lower uptake.ConclusionIn our analysis we found several independent predictors of influenza vaccination. Surprisingly, individuals belonging to lower social classes have higher chances of being vaccinated. These results suggest that vaccination policies have a positive effect in preventing socioeconomic inequalities in access to this service in Italy.     

Influenza vaccination rate and its association with chronic diseases in China: Results of a national cross-sectional study

IntroductionInfluenza vaccination is the most effective way to prevent influenza. Few studies on its rate were reported throughout China and for populations with chronic diseases. An estimation of the rates in China was accomplished.MethodsAll data were from a national cross-sectional survey of a sample representing the population aged 40 years or older in mainland China in 2014–15. A total of 74,484 individuals with complete self-reported influenza vaccination status were analyzed in 2018–19.ResultsThe overall influenza vaccination rate was 2.4% (95% CI 1.4–3.3) with 1.7% (95% CI 1.2–2.2) for the age group 40–59 years and 3.8% (95% CI 1.6–5.9) for the group ≥60 years. The rate was 4.0% (95% CI 2.0–5.9) among people with a chronic disease. People with asthma and people with emphysema had the highest rates (7.1%, 95% CI 3.2–11.0 and 6.6%, 95% CI 3.6–9.7) while people with chronic obstructive pulmonary disease (COPD) and people with chronic bronchitis had the lower rates (3.6%, 95% CI 2.0–5.2 and 4.8%, 95% CI 2.6–7.0). The rate was the highest among former smokers (3.3%, 95% CI 2.3–4.4) compared to current smokers (1.8%, 95% CI 0.9–2.7) and never smokers (2.5%, 95% CI 1.4–3.6). People living with finance-reimbursed vaccination policy, a positive factor for vaccination, had a higher vaccination rate (11.5%, 95% CI 10.8–12.2) (p < 0.05). People with older age, higher education level, occupation of professionals or technical personnel, living in rural areas or Northern China, former/never smoking were more likely to be vaccinated (p < 0.05).ConclusionsThe influenza vaccination rate is low among adults aged ≥40 years, those ≥60 years and those with chronic diseases in China. Reimbursement policy targeting the elderly should be implemented widely and strategies towards patients with chronic diseases need urgent attention to increase the influenza vaccination coverage.     

Effects of annual influenza vaccination on mortality and hospitalization in elderly patients with ischemic heart disease: a nationwide population-based study

Objective

The effects of influenza vaccination on ischemic heart disease (IHD) patients remain controversial. The purpose of this study was to evaluate the effects of influenza vaccination on all-cause mortality and hospitalization for cardiovascular disease in elderly IHD patients.

Methods

Elderly patients (> 65 years old) with IHD, including ischemic heart failure and coronary artery disease between January 1997 and September 2002 were identified by using the Taiwan National Health Insurance Research Database. The association between influenza vaccination and all-cause mortality and hospitalization due to cardiovascular disease was analyzed.

Results

We included 5048 patients. During the influenza season, influenza vaccination was associated with a reduced risk of all-cause mortality [hazard ratio (HR), 0.42; 95% confidence interval (CI) 0.35-0.49] and hospitalization for cardiovascular disease (HR, 0.84; 95% CI, 0.76-0.93). During the non-influenza season, vaccination was associated with a reduced risk of mortality (HR, 0.78; 95% CI, 0.68-0.90) in elderly IHD patients.

Conclusion

Influenza vaccination was associated with a reduced risk of all-cause mortality in elderly IHD patients throughout the whole year, as well as a reduced risk of hospitalization during the influenza season.     

The free vaccination policy of influenza in Beijing,China: The vaccine coverage and its associated factors

BackgroundIn order to improve influenza vaccination coverage, the coverage rate and reasons for non-vaccination need to be determined. In 2007, the Beijing Government published a policy providing free influenza vaccinations to elderly people living in Beijing who are older than 60. This study examines the vaccination coverage after the policy was carried out and factors influencing vaccination among the elderly in Beijing.MethodsA cross-sectional survey was conducted through the use of questionnaires in 2013. A total of 1673 eligible participants were selected by multistage stratified random sampling in Beijing using anonymous questionnaires in-person. They were surveyed to determine vaccination status and social demographic information.ResultsThe influenza vaccination coverage was 38.7% among elderly people in Beijing in 2012. The most common reason for not being vaccinated was people thinking they did not need to have a flu shot. After controlling for age, gender, income, self-reported health status, and the acceptance of health promotion, the rate in rural areas was 2.566 (95% confidence interval [CI], 1.801–3.655, P < 0.010) times greater than that in urban areas. Different mechanisms of health education and health promotion have different influences on vaccination uptake. Those whom received information through television, community boards, or doctors were more likely to get vaccinated compared to those who did not (Odds Ratio [OR] = 1.403, P < 0.010; OR = 1.812, P < 0.010; OR = 2.647, P < 0.010).ConclusionThe influenza vaccine coverage in Beijing is much lower than that of developed countries with similar policies. The rural–urban disparity in coverage rate (64.1% versus 33.5%), may be explained by differing health provision systems and personal attitudes toward free services due to socioeconomic factors. Methods for increasing vaccination levels include increasing the focus on primary care and health education programs, particularly recommendations from doctors, to the distinct target populations, especially with a focus on expanding these efforts in urban areas.     

Deaths averted by influenza vaccination in the U.S. during the seasons 2005/06 through 2013/14

BackgroundExcess mortality due to seasonal influenza is substantial, yet quantitative estimates of the benefit of annual vaccination programs on influenza-associated mortality are lacking.MethodsWe estimated the numbers of deaths averted by vaccination in four age groups (0.5 to 4, 5 to 19, 20 to 64 and ≥65 yrs.) for the nine influenza seasons from 2005/6 through 2013/14. These estimates were obtained using a Monte Carlo approach applied to weekly U.S. age group-specific estimates of influenza-associated excess mortality, monthly vaccination coverage estimates and summary seasonal influenza vaccine effectiveness estimates to obtain estimates of the number of deaths averted by vaccination. The estimates are conservative as they do not include indirect vaccination effects.ResultsFrom August, 2005 through June, 2014, we estimated that 40,127 (95% confidence interval [CI] 25,694 to 59,210) deaths were averted by influenza vaccination. We found that of all studied seasons the most deaths were averted by influenza vaccination during the 2012/13 season (9398; 95% CI 2,386 to 19,897) and the fewest during the 2009/10 pandemic (222; 95% CI 79 to 347). Of all influenza-associated deaths averted, 88.9% (95% CI 83 to 92.5%) were in people ≥65 yrs. old.ConclusionsThe estimated number of deaths averted by the US annual influenza vaccination program is considerable, especially among elderly adults and even when vaccine effectiveness is modest, such as in the 2012/13 season. As indirect effects (“herd immunity”) of vaccination are ignored, these estimates represent lower bound estimates and are thus conservative given valid excess mortality estimates     

A prospective study of influenza vaccination and time to pregnancy

BackgroundAlthough pregnancy planners are a priority group for influenza vaccination in the United States, little is known about the extent to which influenza vaccination affects fecundability.MethodsWe analyzed data from Pregnancy Study Online (PRESTO), an ongoing preconception cohort study of North American pregnancy planners. During June 2013 to August 2019, 8654 female participants and 2137 of their male partners completed a baseline questionnaire and were followed until reported pregnancy, fertility treatment initiation, loss to follow-up, or 12 menstrual cycles of attempt time, whichever came first. At baseline, male and female participants reported whether they received an influenza vaccination in the past year and the date of vaccination. We used proportional probabilities regression models to estimate fecundability ratios (FR) and 95% confidence intervals (CI) comparing those who did and did not report influenza vaccination, adjusting for demographics, anthropometrics, behavioral factors, and medical history.ResultsInfluenza vaccination in the past year was more common among female participants than male participants (47% vs. 37%). FRs were 1.04 (95% CI: 0.98–1.10) for female vaccination and 1.03 (95% CI: 0.93–1.14) for male vaccination. Among the 2137 couples with complete data on both partners, for 40% neither partner was vaccinated, 23% had female-only vaccination, 9% had male-only vaccination, and in 28% both partners were vaccinated. Compared with couples in which neither participant was vaccinated, FRs were 1.13 for female-only vaccination (95% CI: 0.99–1.29), 0.94 for male-only vaccination (95% CI: 0.78–1.12), and 1.07 when both partners were vaccinated (95% CI: 0.94–1.21). When restricted to recent vaccination before peak influenza season, results were similar.ConclusionsOur data indicate no adverse effect of influenza vaccination on fecundability.     

Economic assessment of a high-dose versus a standard-dose influenza vaccine in the US Veteran population: Estimating the impact on hospitalization cost for cardio-respiratory disease

ObjectiveTo compare the economic impact of high-dose trivalent (HD) versus standard-dose trivalent (SD) influenza vaccination on direct medical costs for cardio-respiratory hospitalizations in adults aged 65 years or older enrolled in the United States (US) Veteran’s Health Administration (VHA).MethodsLeveraging a relative vaccine effectiveness study of HD versus SD over five respiratory seasons (2010/11 through 2014/15), we collected cost data for healthcare provided to the same study population both at VHA and through Medicare services. Our economic assessment compared the costs of vaccination and hospital care for patients experiencing acute cardio-vascular or respiratory illness.ResultsWe analyzed 3.5 million SD and 158,636 HD person-seasons. The average cost of HD and SD vaccination was $23.48 (95% CI: $21.29 - $25.85) and $12.21 (95% CI: $11.49 - $13.00) per recipient, respectively, while the hospitalization rates for cardio-respiratory disease in HD and SD recipients were 0.114 (95% CI: 0.108–0.121) and 0.132 (95% CI: 0.132–0.133) per person-season, respectively. Attributing the average cost per hospitalization of $11,796 (95% CI: $11,685 - $11,907) to the difference in hospitalization rates, we estimated savings attributable to HD to be $202 (95% CI: $115 – $280) per vaccinated recipient.ConclusionsFor the five-season period of 2010/11 through 2014/15, HD influenza vaccination was associated with net cost savings due to fewer hospitalizations, and therefore lower direct medical costs, for cardio-respiratory disease as compared to SD influenza vaccination in the senior US VHA population.     

Multimorbidity is associated with uptake of influenza vaccination

ObjectivePatients with chronic conditions have higher rates of severe influenza-related illness and mortality. However, influenza vaccination coverage in high-risk populations continues to be suboptimal. We describe the association between cumulative disease morbidity, measured by a previously validated multimorbidity index, and influenza vaccination among community-dwelling adults.MethodsWe obtained interview and medical record data for participants ≥18 years who sought outpatient care for influenza-like illness between 2011 and 2016 as part of an outpatient-based study of influenza vaccine effectiveness. We defined cumulative disease morbidity by using medical diagnosis codes to calculate a multimorbidity-weighted index (MWI) for each participant. MWI and influenza vaccination status was evaluated by logistic regression. Akaike information criterion was calculated for all models.ResultsOverall, 1458 (48%) of participants out of a total of 3033 received influenza vaccination. The median MWI was 0.9 (IQR 0.00–3.5) and was higher among vaccinated participants (median 1.6 versus 0.0; p < 0.001). We found a positive linear association between MWI and vaccination, and vaccination percentages were compared between categories of MWI. Compared to patients with no multimorbidity (MWI = 0), odds of vaccination were 17% higher in the second category (MWI 0.01–1.50; [OR: 1.17, 95% CI: 0.92–1.50]), 58% higher in the third category (MWI 1.51–3.00; [OR: 1.58, 95% CI: 1.26–1.99]), 130% higher in the fourth category (MWI 3.01–6.00; [OR: 2.30, 95% CI: 1.78–2.98]) and 214% higher in the fifth category (MWI 6.01–45.00;[OR: 3.14, 95% CI: 2.41–4.10]). Participants defined as high-risk had 86% greater odds of being vaccinated than non-high-risk individuals (OR: 1.86, 95% CI: 1.56–2.21). The AIC was lowest for MWI compared with high-risk conditions.ConclusionsOur results suggest a dose response relationship between level of multimorbidity and likelihood of influenza vaccination. Compared with high-risk condition designations, MWI provided improved precision and a better model fit for the measurement of chronic disease and influenza vaccination.     

Effectiveness of the influenza vaccine at reducing adverse events in patients with heart failure: A systematic review and meta-analysis

BackgroundThe association between influenza and adverse vascular events in patients with heart failure is well documented. The effect of the influenza vaccine on preventing such adverse events is uncertain. This systematic review and meta-analysis addressed whether vaccination against influenza reduces adverse vascular events and mortality in heart failure patients.MethodsMEDLINE and EMBASE databases were comprehensively searched, study screening and quality assessment were completed, and data was synthesized. Eligible studies investigated heart failure patients who received the influenza vaccine, and reported outcomes within 12 months, compared to heart failure patients who did not receive the influenza vaccine. The following 6 outcomes were assessed: all-cause mortality, cardiovascular-related mortality, all-cause hospitalization, cardiovascular-related hospitalization, non-fatal myocardial infarction, and non-fatal stroke. Risk of bias was assessed using the Newcastle-Ottawa Scale and a GRADE assessment was completed. A random-effects meta-analysis was performed to estimate the pooled risk ratio (RR), 95% confidence intervals (CIs), and heterogeneity using I² statistics.ResultsAfter synthesizing data from 7 non-randomized studies (247,842 patients), the results demonstrate the risk of all-cause mortality is significantly reduced within 12 months of a heart failure patient receiving the influenza vaccine (RR = 0.75, 95% CI 0.71–0.79; P<0.0001); very low certainty of evidence. The risk of cardiovascular-related mortality was significantly reduced (RR = 0.77, 95% CI 0.73–0.81; P<0.0001); low certainty of evidence. The pooled risk of all-cause hospitalization was higher among vaccinated heart failure patients (RR = 1.24, 95% CI 1.13–1.35; P<0.0001), based on two studies; very low certainty of evidence and considerable heterogeneity (I² = 90%). No eligible studies assessed cardiovascular-related hospitalization, non-fatal myocardial infarction, or non-fatal stroke.ConclusionsInfluenza vaccination appears to reduce adverse cardiovascular events, although the certainty of the evidence is low or very low. Rigorous randomized controlled trial evidence is needed to further examine the protective effect of the influenza vaccine in heart failure patients.     

The impact of socioeconomic level on influenza vaccination among Italian adults and elderly: a cross-sectional study

OBJECTIVE: To assess the predictive factors of influenza vaccination among Italian adults, focusing on socioeconomic differences. METHODS: A cross-sectional study was carried out using interview and self-reported data on 102,095 subjects aged 25-89 years from the national survey "health conditions and health care services use" conducted in Italy in 1999-2000. Analyses were stratified by age and multiple logistic regression models were used to estimate odds ratios (OR) of influenza vaccination. RESULTS: Approximately one in six individuals (17.3%) received an influenza vaccine in the previous 12 months. Older age, poor health status and former smoking were all positively associated with influenza vaccination (P-value<0.05). Lower educated individuals and subjects with manual occupations were less likely to be vaccinated than those better off, with an OR ranging from 0.65 (95% CI 0.55, 0.77) to 0.82 (95% CI 0.71, 0.93). Among individuals aged 65-89 there was no apparent influence of both variables on the likelihood of receiving the influenza vaccine. CONCLUSIONS: Socioeconomic inequalities in influenza vaccine uptake were present among the adults but not among the elderly. Because in Italy the National Health Service provides influenza vaccination to the elderly free of charge, it is possible that this policy attenuated the socioeconomic differential.     

Effectiveness of influenza vaccination in elderly diabetic patients: A retrospective cohort study

Purpose

Studies regarding the clinical benefits of influenza vaccination in diabetic patients are limited. This study evaluated if the elderly diabetic patients who have had influenza vaccination would have benefits such as reduced medical care and mortality.

Methods

We used the universal insurance claims data from 2001 to 2009 in Taiwan to identify annual elderly patients with diabetes cohorts with (N = 4454) and without (N = 4571) influenza vaccination. The risk of developing pneumonia or influenza, respiratory failure, intensive care, hospitalization, and mortality were measured and compared between cohorts within one year of follow-up.

Results

The vaccine cohort had lower incidences of pneumonia or influenza and respiratory failure compared with the non-vaccine cohort. More importantly, the vaccine cohort had a hospitalization rate that was 11% less than the non-vaccine cohort (29.6 vs. 33.1 per 100 person-years) with an adjusted hazard ratio (HR) of 0.88 (95% CI 0.81–0.96). The vaccine cohort was also less likely to be admitted to the intensive care unit (ICU) [0.58 vs. 2.05 per 100 person-year; adjusted HR 0.30 (95% CI 0.19–0.47)] and less likely to expire [3.13 vs. 7.96 per 100 person-year; adjusted HR 0.44 (95% CI 0.36–0.54)]. Influenza vaccination reduced the hospitalization cost by 1282.6 USD, compared with patients without influenza vaccination (95% CI −2210.3, −354.8).

Conclusion

Influenza vaccination is associated with a reduced risk of morbidity, hospitalization, ICU admissions, and mortality. In addition, the hospitalization cost is reduced.     

Effect of statin use on the risk of medically attended acute respiratory illness among influenza vaccinated elderly

ObjectivesThe immunomodulatory effects of statins may reduce the immune response induced by influenza vaccines. However, evidence regarding the effect of statin use on the effectiveness of seasonal influenza vaccines against medically attended acute respiratory illness (MAARI) in the elderly remains scarce.MethodsWe conducted a retrospective cohort study using data from Taiwan’s National Health Insurance Research Database. Elderly adults aged ≧ 66 years who were vaccinated with seasonal influenza vaccines during the 2007–2008 to 2012–2013 influenza seasons were enrolled for this analysis. We compared the risk of MAARI between statin and non-statin users. Propensity score matching and conditional logistic regression models were used to analyze the data.ResultsA total of 440,180 elderly were included in this study. In general, the risk of MAARI was higher in statin users than non-statin users (odds ratio [OR]: 1.03, 95% confidence interval [CI]: 1.02–1.05). Statin exposure after vaccination was associated with a higher risk of MAARI (OR: 1.05, 95% CI: 1.02–1.07). Among different statin agents, simvastatin and lovastatin use was associated with a significant increase in the risk of MAARI (OR_simvastatin: 1.14, 95% CI: 1.10–1.18; OR_lovastatin: 1.18, 95% CI: 1.12–1.25).ConclusionsStatin exposure, especially simvastatin and lovastatin, was associated with a higher risk of MAARI in the seasonal influenza vaccinated elderly. Future studies exploring the differences between individual statins and mechanisms of their immunomodulatory effects are necessary.     

Influenza vaccine effectiveness against influenza-associated hospitalization in 2015/16 season,Beijing, China

BackgroundVaccination is recommended to prevent influenza virus infection and associated complications. This study aimed to estimate the influenza vaccine effectiveness (VE) against hospitalization in the 2015/16 season in Beijing.MethodsPatients who were hospitalized in the 5 study hospitals between 1 Oct 2015 and 15 May 2016 were recruited. Influenza vaccination status was obtained for PCR-confirmed influenza patients and the selected controls who tested negative for the virus. Conditional logistic regression was used to estimate the influenza VE matching by calendar week, and adjusting for age, study sites, underlying medical conditions, smoking status, and hospital admissions over the past 12 months.ResultsThe overall VE was −37.9% (95% CI: −103.3, 6.5) against laboratory-confirmed influenza-associated hospitalization. The 2015–16 seasonal vaccine was had −61.9% (95% CI: −211.9, 15.9), −5.4% (95% CI: −108.1, 46.6) and −45.2% (95% CI: −152.6, 16.5) effectiveness to prevent infection from A(H1N1)pdm09, A(H3N2) and influenza B, respectively.ConclusionsInfluenza vaccination did not show effective protection against hospitalization with influenza in 2015/16 season in Beijing.