Trends In Influenza Vaccination Coverage Research Articles

Trends in influenza vaccine coverage in the Portuguese population: Are there contributing factors?

Introduction In Portugal as in most European countries, annual influenza vaccination is recommended for certain groups at-risk of post-infection complication, namely the elderly. The annual monitoring of the influenza vaccine (IV) coverage allows understanding the success of the vaccination program on a given season. On the other hand, evaluating IV coverage over a long period of time permits understanding factors that contribute to the trend and evolution of the vaccine coverage in specific groups of the population. In public health perspective, and considering that IV coverage is below the desirable target in all groups for which is recommended, it is important to understand what factors contribute to the IV coverage. This study aims to analyse trends in influenza vaccine coverage in the Portuguese population, overall and in specific age groups, and identify factors that contribute to the IV coverage evolution. Methods We used data from a population-based survey conducted annually to estimate IV coverage (ECOS panel) from 1998 to 2015. ECOS is composed by a sample of approximately 1000 households stratified by region (homogeneous allocation) selected from a dual sample frame - random digit dialing mobile and landline phones (ECOS sample). The relevant information is collected by Computer Assisted Telephone interview (CATI) using with the same questionnaire every year and one respondent by household (proxy for the rest of the household members). IV coverage was estimated taking in consideration the design effect. Meta-regression was used to test a linear trend in IV coverage. Models were fitted with the logit of the IV as dependent variable, weighting each survey estimate by the inverse of variance in the logit scale and adjusted for influenza related events [SARS, A(H5N1) and A(H1N1)2009 pandemic]. For the 65 and plus age group, the introduction of free vaccination (in the 2012/13 season) was also modelled. These events where tested given their direct effect on IV recommendations. Results Overall IV coverage estimates varied between 14.2% (95% CI: 11.6; 16.8) in the 1998/99 season and 19.5% (95% CI: 17.6% a 21.6%) in the 2009/10 season. Meta-regression results indicate a non-statistical significant increasing trend of IV coverage along the 18 years in analyse (OR = 1.01; 95% CI: 0.99–1.02). All influenza related events, had an increasing effect on increasing the IV coverage [SARS 2003–2004 - OR = 1.23; 95% CI = 1.02 to 1.48; A(H1N5) 2005–2006 - OR = 1.26; 95% CI = 1.05 to 1.51 and A(H1pdm09) 2009–2010 - OR = 1.25; 95% CI = 1.03 to 1.50]. Age stratified analysis revealed a decreasing IV coverage trend in children with less than 14 years (OR = 0.94; 95% CI = 0.89 to 0.99), an increasing trend in the elderly population (OR = 1.05; 95% CI= 1.02 to 1.09) and no trend in the remain age groups (15–44 years: OR = 0.99; 95% CI: 0.97 to 1.02 and 45-64 years: OR = 1.00; 95% CI: 0.9 to 1.02). None of the influenza related events influenced IV coverage in children. Equivalent results were observed in the elderly, where none of the tested influenza related events or the introduction of free vaccines in this age group revealed an impact on IV coverage. Conclusion Overall results indicate that periods with threats of circulating virus with severe consequences for health have an impact on IV coverages, towards increasing the vaccine coverage. This result may be related to a higher awareness of health risks during such periods and the adoption of influenza vaccine uptake. However, after age stratification, all these events and including the free vaccine for elderly had no impact on respective IV coverages. Further analysis should be performed in order to identify factors that are influencing the trend in the age stratified IV coverage.

Trends in Influenza and Pneumococcal Vaccination Among US Nursing Home Residents, 2006-2014

BackgroundInstitutionalized adults are at increased risk of morbidity and mortality from influenza and pneumococcal infection. Influenza and pneumococcal vaccination have been shown to be effective in reducing hospitalization and deaths due to pneumonia and influenza in this population. ObjectiveTo assess trends in influenza vaccination coverage among US nursing home residents from the 2005-2006 through 2014-2015 influenza seasons and trends in pneumococcal vaccination coverage from 2006 to 2014 among US nursing home residents, by state and demographic characteristics. MethodsData were analyzed from the Centers for Medicare and Medicaid Services' (CMS's) Minimum Data Set (MDS). Influenza and pneumococcal vaccination status were assessed for all residents of CMS-certified nursing homes using data reported to the MDS by all certified facilities. ResultsInfluenza vaccination coverage increased from 71.4% in the 2005-2006 influenza season to 75.7% in the 2014-2015 influenza season and pneumococcal vaccination coverage increased from 67.4% in 2006 to 78.4% in 2014. Vaccination coverage varied by state, with influenza vaccination coverage ranging from 50.0% to 89.7% in the 2014-2015 influenza season and pneumococcal vaccination coverage ranging from 55.0% to 89.7% in 2014. Non-Hispanic black and Hispanic residents had lower coverage compared with non-Hispanic white residents for both vaccines, and these differences persisted over time. ConclusionInfluenza and pneumococcal vaccination among US nursing home residents remains suboptimal. Nursing home staff can employ strategies such as provider reminders and standing orders to facilitate offering vaccination to all residents along with culturally appropriate vaccine promotion to increase vaccination coverage among this vulnerable population.

Trends in influenza vaccine coverage and vaccine hesitancy in Canada, 2006/07 to 2013/14: results from cross-sectional survey data.

Past studies have reported influenza vaccination coverage below national targets, but up-to-date estimates are needed to understand trends and to identify areas for intervention. The objective of this study was to describe recent trends in influenza vaccination in Canada, timing of uptake and reasons for not receiving the vaccine. We pooled data from the 2007 to 2014 cycles of the Canadian Community Health Survey. Using bootstrapped survey weights, we examined influenza vaccine coverage by various groups, including by age and by presence of chronic medical conditions. The overall sample included 481 526 respondents. Across all survey cycles combined, 29% of respondents reported receiving seasonal influenza vaccination in the past 12 months. Coverage levels were fairly consistent during the study period, but varied by province or territory. Vaccination coverage decreased over time among those aged 65 years and older. Among those who received a vaccination, it was most common to do so in October or November. Among those not vaccinated, the most frequently cited reason was believing it was unnecessary. Influenza vaccination coverage continues to fall below national targets, with substantial declines seen among those aged 65 years and older, a group for which vaccination is particularly important. More intensive efforts are needed to improve coverage in Canada, particularly for high-risk groups.

Trends in influenza vaccination coverage in Portugal from 1998 to 2010: effect of major pandemic threats

BackgroundVaccination is the key measure available for prevention of the public health burden of annual influenza epidemics. This article describes national trends in seasonal influenza vaccine (IV) coverage in Portugal from 1998/99 to 2010/11, analyzes progress towards meeting WHO 2010 coverage goals, and addresses the effect of major public health threats of the last 12 years (SARS in 2003/04, influenza A (H5N1) in 2005/06, and the influenza A (H1N1)2009 pandemic) on vaccination trends.MethodsThe National Institute of Health surveyed (12 times) a random sample of Portuguese families. IV coverage was estimated and was adjusted for age distribution and country region. Independence of age and sex coverage distribution was tested using a modified F-statistic with a 5% significance level. The effect of SARS, A (H5N1), and the A (H1N1)2009 pandemic was tested using a meta-regression model. The model was adjusted for IV coverage in the general population and in the age groups.ResultsBetween 1998/99 and 2010/11 IV, coverage in the general population varied between 14.2% (CI 95%: 11.6%–16.8%) and 17.5% (CI 95%: 17.6%–21.6%). There was no trend in coverage (p = 0.097). In the younger age group (<15 years) a declining trend was identified until 2008/09 (p = 0.005). This trend reversed in 2009/10. There was also a gradual and significant increase in seasonal IV coverage in the elderly (p for trend < 0.001). After 2006/07, IV coverage remained near 50%. Adjusting for baseline trends, there was significantly higher coverage in the general population in 2003/04 (p = 0.032) and 2005/06 (p = 0.018). The high coverage observed in the <15-year age group in season 2009/10 was also significant (p = 0.015).ConclusionsIV coverage in the elderly population displayed an increasing trend, but the 75% WHO 2010 target was not met. This result indicates that influenza vaccination strategy should be improved to meet the ambitious WHO coverage goals. The major pandemic threats of the past decade had a modest but significant effect on seasonal influenza vaccination. There was an increase in vaccine uptake proportion in the general population in 2003/04 and in 2005/06, and in individuals <15 years old in 2009/10.

Trends in influenza vaccine coverage among primary healthcare workers in Spain, 2008–2011

ObjectiveTo evaluate trends in seasonal influenza vaccination coverage in primary healthcare workers (PHCWs) in Spain between 2008 and 2011. MethodsWe made an anonymous web survey of PHCWs in 2012. Information on attitudes towards and knowledge of influenza vaccine, and immunization in previous seasons was collected. Self-reported vaccination coverage and factors related to vaccination continuity were analysed. ResultsOf 5433 workers contacted, 2625 (48.3%) responded to the survey: 47.0% were general practitioners, 10.3% paediatricians and 42.7% nurses. Their reported vaccination rates from seasons 2008–2009 to 2011–2012 decreased over time: 58.4%, 57.4%, 53.2% and 49.3% (linear trend, p<0.001). Among workers vaccinated in any previous season, 70.2% were vaccinated again in 2011–2012, compared with 5.2% among those not previously vaccinated (p<0.001). Continuity of vaccination increased with age and with the worker or cohabitant having a major chronic condition. Vaccination was higher in workers who recognized vaccination as effective and those worried about being infected or infecting patients. ConclusionInfluenza vaccination coverage in PHCWs has declined, especially after the pandemic. Intensive interventions are needed to change this trend. Knowledge of vaccination should be reinforced by stressing the effectiveness of the vaccine and the risks of influenza for workers and patients.

Trends in Influenza Vaccine Coverage in Pregnant Women, 2008 to 2012

Pregnant women are at increased risk of severe influenza-related complications and hospitalizations and are a priority group for influenza vaccination. To examine coverage of seasonal and pandemic influenza A (H1N1) vaccines in pregnant women in a managed care setting, from 2008 to 2012. Retrospective cohort study of 10,145 pregnant women. H1N1 and seasonal influenza vaccination rates. Seasonal influenza vaccine coverage increased from 38% to 63% between the 2008-2009 and 2010-2011 seasons, and then dropped to 61% in 2011-2012. Vaccine coverage was higher in women considered at high risk of influenza complications, increasing from 43% in 2008-2009 to 71% in 2010-2011, before decreasing to 69% in 2011-2012. H1N1 vaccine coverage was greater than seasonal influenza coverage in 2009-2010 in the overall pregnant population (61% vs 53%) and in the high-risk group (64% vs 59%). We observed statistically significant differences in vaccination rates by trimester, gravidity, maternal age, and race/ethnicity. Vaccination rates increased significantly from 2008 to 2011, then dropped slightly in 2011-2012. Continued efforts are needed to ensure adequate vaccination coverage in this high-risk population.

Influenza vaccine coverage among children under the age of 5 years in Poland during 2004-2008

IntroductionInfluenza is a considerable health problem all over the world. The most important group for influenza vaccination are children: the highest attack rate during community out-breaks of influenza can be found among school-aged children or their family members; children bear a considerable risk for complications due to influenza, leading to an increased need for healthcare resources (including hospitalization). The high level of vaccine coverage among school children could provide protection against influenza among households and could reduce mortality rates among older individuals.ObjectiveThe aim of this study was to estimate the influenza vaccine coverage among children younger than 5 years and to find any trends in influenza vaccine coverage in 2004-2008 in Poland.Material and methodsOfficial data (number of administrated vaccines and the age of vaccinated individuals) collected by the National Institute of Hygiene, the National Institute of Public Health, and the Central Statistical Office in Poland were analyzed. This data are reported by physicians and collected from reports prepared annually by the Sanitary-Epidemiological Stations at a local level. The vaccine coverage rate was calculated as a percentage of vaccinated individuals among all children under the age of 5 years.ResultsThe influenza vaccine coverage among children younger than 5 years varied from 1% (2007 and 2008) to 1.9% (2005). The proportion of vaccinated children aged less than 5 compared with the total number of flu shots administrated irrespective of age also varied from 1.4% (2007) to 2% (2005).ConclusionsThe influenza vaccination coverage among Polish children aged less than 5 years is low and has persisted at the same level. More educational activities directed both to patients (parents) and healthcare workers would be needed to improve a general knowledge about influenza vaccination benefits among young children.

Évolution du taux de couverture vaccinale contre la grippe en France : de 2001 à 2006

Introduction The increased risk of a new influenza pandemic has raised awareness of the need for high influenza vaccination rates. Objectives This study aims at assessing trends in influenza vaccination coverage from 2001 to 2006 in France, at understanding the drivers and barriers, and to identify vaccination intentions for 2006/2007. Methods We conducted a mail-based household survey on 9835 persons representative of the population from age 15. Essentially, the same questionnaire was used in all seasons. Results The influenza vaccination coverage rate slightly increased, reaching 24.2% in 2005/2006 (70.1% in patients over 65). In the last two seasons the fact that the vaccination was provided for free was the most frequent reason for getting vaccinated. Older age, considering influenza as a serious disease and recommendations from the family doctor or nurse were also important drivers for vaccination. Only 2% of those vaccinated in 2005/2006 indicated the threat of avian influenza as a reason. The reasons for non-vaccination among persons never vaccinated before were feeling too young for vaccination, never having considered vaccination before and absence of recommendation by the family doctor. Among those who were previously vaccinated but not in the current season, the reasons for not being vaccinated were not finding vaccination necessary, forgetfulness and having influenza-like illness despite vaccination. Conclusion Stable vaccination rates were observed from 2001 to 2006. France is well on its way to reach the international vaccination goal set by the WHO (75% in the elderly population), but continuously effort is needed for others.

Developments in influenza vaccination coverage in England, Scotland and Wales covering five consecutive seasons from 2001 to 2006

This study aims at assessing trends in influenza vaccination coverage from 2001 to 2006 in Great Britain, at understanding drivers and barriers to vaccination and at identifying vaccination intentions for influenza season 2006/2007. In seasons 2001/2002 to 2005/2006, telephone-based household surveys representative of the population from age 16 were conducted, with about 2000 interviews per season (10,095 in total). Overall influenza vaccination coverage rate in Great Britain reached 25.9% in season 2005/2006. A sub-analysis showed that the highest coverage was reported in Wales reaching 33.3%. In the elderly recommended vaccination (from age 65), the coverage reached 79% in 2005/2006. Advice from the family doctor and the perception that influenza is a serious illness were the most frequent reasons for getting vaccinated. The most frequent reasons for not getting vaccinated, in persons never vaccinated before, were that they had not considered immunisation or had not received a recommendation from their family doctor. Those vaccinated in the past but not in the current season said they had not thought about vaccination/forgot. A gap continues to exist between those with intention to get vaccinated and those actually vaccinated, indicating a potential to increase vaccination coverage rate in the future. Our study shows that stable vaccination coverage rates were observed from 2002 to 2006 in Great Britain. The coverage had increased in Wales and in Scotland. The coverage among the elderly above 65 years was the highest in Europe. Although Great Britain complies with national and international goals of vaccination coverage rates effort is needed to ensure high vaccination coverage rates at the same level in the future.

Developments in influenza vaccination coverage in Italy over five seasons (2001-2006).

This study aims at assessing trends in influenza vaccination coverage from 2001 to 2006 in Italy, at understanding the drivers and barriers to vaccination, and to identify vaccination intentions for season 2006/07. We conducted telephone-based household surveys representative of the population from age 14. Total sample size was 10,026 persons. The influenza vaccination coverage rate in Italy increased over the years, reaching 24.1% in season 2005/06. In the elderly (> 65), the vaccination rate reached 63.4% in 2005/06. The increase between seasons 2004/05 and 2005/06 was statistically significant. A recommendation for the doctor/nurse, considering influenza as a serious illness, older age and not being in very good health were the most frequent reasons for getting vaccinated. Four percent of those vaccinated in 2005/06 indicated the threat of avian flu as a reason. For the winter 2006/07, 30% of the population intended to get vaccinated, indicating the potential to increase vaccination coverage next year. The threat of avian influenza may have contributed to a substantial recent increase in season 2005/06 as compared to the year before. Despite of this positive evolution, major effort is still needed to reach WHO objectives for 2010 (75% vaccination coverage rate in the elderly population).

Predictors of Influenza Vaccination in HIV‐Infected Patients in the United States, 1990–2002

Although annual influenza vaccination of human immunodeficiency virus (HIV)-infected patients has been recommended in the United States since the early 1990s, vaccine coverage in this population is reported to be low. The objectives of the present study were to assess trends in influenza vaccination coverage in HIV-infected patients and to determine predictors of influenza vaccination. We analyzed data from the medical records of 51,021 HIV-infected patients from 10 US cities observed in a longitudinal cohort study between 1990 and 2002. Using multivariate logistic regression, we determined predictors of influenza vaccination for both the pre-highly active antiretroviral therapy (HAART) and HAART eras. Vaccination coverage increased from 28.5% in the 1990 to 41.6% in the 2002 influenza season. Vaccine coverage increased with increasing age and frequency of medical visits. In the HAART era, persons prescribed antiretroviral therapy were more likely and those with higher viral loads and lower CD4 T cell counts were less likely to have received influenza vaccine. Although influenza vaccination coverage in this population has increased in recent years, it is well below the Healthy People 2010 target of 60%. Efforts should be undertaken to increase influenza vaccination in HIV-infected persons.

Influenza vaccination trends among adults 65 years or older in the United States, 1989-2002.

Influenza vaccination of elderly individuals (65 years or older) has been recommended in the United States since 1961, and consistent surveillance of vaccine use has been conducted since 1989. We examined national trends in influenza vaccination coverage in the United States from 1989 to 2002 among noninstitutionalized elderly individuals and identified factors associated with receipt of influenza vaccine. We analyzed data from the 1989-2002 National Health Interview Surveys, weighted to reflect the civilian, noninstitutionalized US population to determine self-reported levels of influenza vaccination. We conducted multivariable logistic regression modeling of 2002 data to identify factors independently associated with self-reported influenza vaccination. Among the elderly, influenza vaccination coverage increased from 30.5% in 1989 to 65.6% in 2002, with only a 2.4% increase from 1997 to 2002. In 2002, coverage remained lower for the non-Hispanic black (49.6%) and Hispanic (48.5%) populations compared with non-Hispanic whites (68.6%). Characteristics associated with a lower likelihood of influenza vaccination included fewer than 4 physician contacts in the past year and whether a person (1) was divorced or separated, (2) was non-Hispanic black or Hispanic, (3) had no regular physician, and (4) had less than a high school education. Individuals with chronic medical conditions and those 75 years or older were more likely to be vaccinated. By 1997, influenza vaccination coverage exceeded the Healthy People 2000 objective of 60% for the elderly overall, but even by 2002, this objective was still not achieved in the elderly black and Hispanic populations. Vaccination coverage seems to be leveling off, and innovative initiatives are needed to reach the Healthy People 2010 target of 90%, especially among racial and ethnic minorities.

Evolución en las coberturas vacunales antigripales en la Comunidad de Madrid entre los años 1993 y 2001

Background The influenza vaccine is a safe and effective preventive measure. The aims of this study were to estimate influenza vaccination coverage in 1993 and 2001, to describe the factors associated with vaccination and to asses trends in influenza vaccination coverage between these years in the Autonomous Community of Madrid (Spain). Subjects and method Data from 1,985 and 1,998 adults living in the Autonomous Community of Madrid and included in the Spanish National Health Surveys of 1993 and 2001 were analyzed. The vaccination coverage for each year was calculated and the influence of age, gender and the presence of chronic disease was assessed. Logistic regression was used to determine which of these variables had an independent effect on influenza vaccination and to assess trends in coverage over time. Results For the whole sample we estimated a coverage of 18.6% in 1993 and 19.8% in 2001. In the multivariate model, a significant improvement in the coverage for subjects aged more than 65 years was observed between 1993 and 2001. No change was found in subjects younger than 65 years with chronic disease. Conclusions Vaccination coverage in subjects aged less than 65 years with chronic disease was less than the desired level and did not improve during the study period. Lowering the age limit for the current recommendations for the influenza vaccine in the Autonomous Community of Madrid could improve coverage in the population aged <65 years.