Determinants Of Influenza Vaccine Uptake Research Articles

Non-specific benefit of seasonal influenza vaccine on respiratory syncytial virus-hospitalisations in children: An instrumental variable approach using population-based data

BackgroundSeasonal influenza vaccine is effective against influenza hospitalisations, but little is known about non-specific effects of the vaccine on other respiratory pathogens with similar seasonal patterns. We aimed to assess the causal impact of seasonal influenza vaccine on laboratory-confirmed hospitalisations for respiratory syncytial virus (RSV) in children using an instrumental variable (IV) strategy. MethodsWe used probabilistically linked population-based data on childhood immunisations, births, deaths, hospitalisations, perinatal factors, and microbiology test results (2000–2013) of all Western Australian (WA) children born 2000–2012, observed longitudinally until the earliest of 7 years of age or 31 December 2013. We exploited a unique natural experiment created from the WA’s state-funded preschool influenza vaccination policy commencing in 2008 and used this as an instrument for children’s seasonal influenza vaccination status. We estimated a system of two simultaneous probit equations: determinants of influenza vaccine uptake, and determinants of RSV-confirmed hospitalisation. ResultsInfluenza vaccine coverage was low prior to 2008 but increased to 36 % in children aged 6–23 months in 2009. The majority (90 %) of RSV-hospitalisations occurred in children <2 years. Receipt of influenza vaccine reduced RSV-hospitalisations, especially in those <2 years with a rate reduction of 2.27 per 1000 (95 % CI: −3.26; −1.28), and a smaller rate reduction of 0.53 per 1000 (95 % CI: −1.04; −0.02) in those 2–7 years. Over the 5-year period (2008–2013), the state-funded preschool-influenza vaccine program resulted in 1,193 fewer RSV-hospitalisations. Of these, 793 (67 %) were in young children <2 years. ConclusionsTo our knowledge, this is the first analysis utilising an IV estimation strategy on a population level to assess the causal impact of seasonal influenza vaccine on risk of RSV-hospitalisations. We estimated a small protective effect that warrants further investigation.

Secular trends and determinants of influenza vaccination uptake among patients with cardiovascular disease in Korea: Analysis using a nationwide database.

BackgroundInfluenza vaccination reduces cardiovascular events in patients with cardiovascular disease (CVD). Identifying the factors that affect influenza vaccination uptake can help improve the prognosis in patients with CVD. This study aimed to evaluate the secular trends of influenza vaccination uptake and factors associated with lack of vaccination in individuals with CVD.Materials and methodsWe analyzed the annual trends and factors associated with influenza vaccination among 3,264 patients with CVD, included from the Korea National Health and Nutrition Examination Survey which reflect the health and nutritional status of the nationwide population of Korea conducted between 2007/2008 and 2018/2019. We used a stratified, multistage sampling method.ResultsThe influenza vaccination rate was greater in patients with CVD (53–74%) than in those without CVD (28–40%). Multivariable logistic regression analysis showed that age <50 years [odds ratio (OR), 16.22; 95% confidence interval (CI), 7.72–34.07], 50–64 years (OR, 6.71; 95% CI, 4.37–10.28), male sex (OR, 1.45; 95% CI, 1.14–1.65), and asthma (OR, 0.45; 95% CI, 0.22–0.92) were independently associated with a lack of influenza vaccination. Among patients aged <65 years, smoking (OR, 2.30; 95% CI, 1.31–4.04), college graduation status (OR, 1.81; 95% CI, 1.16–2.82), and hypertension (OR, 0.70; 95% CI, 0.51–0.95) were independently associated with influenza vaccination. For individuals aged 65years, there was no significant determinant of lack of vaccination.ConclusionIn patients with CVD, a continuous increase in the secular trend of influenza vaccination was demonstrated in Korea. Young age, male sex, and non-asthma status were independently associated with lack of influenza vaccination uptake.

1238Estimating the non-specific effects of seasonal influenza vaccine on RSV-hospitalisations in children

Abstract Background Seasonal influenza vaccine is effective against influenza hospitalisations, but little is known about non-specific effects on other respiratory pathogens with similar seasonal patterns. We aimed to assess the causal impact of seasonal influenza vaccine on laboratory-confirmed hospitalisations for respiratory syncytial virus (RSV) in children using an instrumental variable (IV) strategy. Methods We used population-based probabilistically linked data on births, childhood immunisations, deaths, hospitalisations, perinatal and statewide microbiology data (2000-2013) in Western Australia (WA). Our analysis cohort included children up to age 7 years. We exploited WA’s unique preschool influenza vaccination policy commencing in 2008 and used this as an instrument for vaccination status. We estimated a system of two simultaneous probit equations: determinants of influenza vaccine uptake, and determinants of RSV-confirmed hospitalisation. Results Influenza vaccine coverage was low prior to 2008 but increased to 33.7% in children aged 6-23 months in 2009. RSV-hospitalisations ranged from 3.5/1000 children (12-23 months) to 6.4/1000 (6-12 months). Receipt of seasonal influenza vaccine reduced RSV-hospitalisations in the population cohort of children aged &amp;lt;2 years by an average of 0.21% in the same year (p &amp;lt; 0.001). Conclusions To our knowledge, this is the first analysis utilising an IV estimation strategy to assess the impact of influenza vaccine on RSV-hospitalisations. We estimated a small, but highly statistically significant impact that warrants further investigation using contemporary data. Key messages RSV is a leading cause of childhood morbidity. The role of influenza vaccine offering cross protection to RSV could be further explored prior to RSV vaccines being commercially available.

Determinants of Influenza Vaccine Uptake in Patients With Cardiovascular Disease and Strategies for Improvement.

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide. Influenza infection is associated with an increased risk of cardiovascular events (myocardial infarction, stroke, and heart failure exacerbation) and mortality, and all‐cause mortality in patients with CVD. Infection with influenza leads to a systemic inflammatory and thrombogenic response in the host body, which further causes destabilization of atherosclerotic plaques. Influenza vaccination has been shown to be protective against cardiovascular and cerebrovascular events in several observational and prospective studies of at‐risk populations. Hence, many international guidelines recommend influenza vaccination for adults of all ages, especially for individuals with high‐risk conditions such as CVD. Despite these long‐standing recommendations, influenza vaccine uptake among US adults with CVD remains suboptimal. Specifically, vaccination uptake is strikingly low among patients aged <65 years, non‐Hispanic Black individuals, those without health insurance, and those with diminished access to healthcare services. Behavioral factors such as perceived vaccine efficacy, vaccine safety, and attitudes towards vaccination play an important role in vaccine acceptance at the individual and community levels. With the ongoing COVID‐19 pandemic, there is a potential threat of a concurrent epidemic with influenza. This would be devastating for vulnerable populations such as adults with CVD, further stressing the need for ensuring adequate influenza vaccination coverage. In this review, we describe a variety of strategies to improve the uptake of influenza vaccination in patients with CVD through improved understanding of key sociodemographic determinants and behaviors that are associated with vaccination, or the lack thereof. We further discuss the potential use of relevant strategies for COVID‐19 vaccine uptake among those with CVD.

Determinants of influenza vaccine uptake and willingness to be vaccinated by pharmacists among the active adult population in Hungary: a cross-sectional exploratory study

BackgroundMany studies have addressed influenza vaccine uptake in risk-group populations (e.g. the elderly). However, it is also necessary to assess influenza vaccine uptake in the active adult population, since they are considered to be a high-transmitter group. In several countries pharmacists are involved in adult vaccination in order to increase uptake. This study therefore aimed to investigate the determinants of influenza vaccination uptake and examine the willingness to be vaccinated by pharmacists.MethodsA cross-sectional study was conducted among Hungarian adults using a self-administered online questionnaire distributed via social media (Facebook). The questionnaire included five domains: demographics, vaccine uptake, factors that motivated or discouraged vaccination, knowledge and willingness of participants to accept pharmacists as influenza vaccine administrators. Descriptive statistics were applied and logistic regression was conducted to assess the possible determinants of vaccination uptake.ResultsData from 1631 participants who completed the questionnaires were analysed. Almost 58% of respondents (944/1631) had occupational and/or health risk factors for influenza. Just over one-tenth (12.3%;200/1631) of participants were vaccinated during the 2017/18 influenza season, 15.4% (145/944) of whom had a risk factor for influenza. Approximately half of the participants (47.4%) believed that influenza vaccination can cause flu, and just over half of them (51.6%), were not knowledgeable about the safety of influenza vaccine ingredients. Logistic regression found that age, sex, health risk factor and knowledge on influenza/influenza vaccination were associated with influenza vaccination uptake (p < 0.05). The most frequently cited reason for having an influenza vaccination was self-protection (95.0%). The most common reason given for refusing the influenza vaccine was that the respondent stated they rarely had an infectious disease (67.7%). The number of participants who were willing to be vaccinated by pharmacists was two-times higher than the number of participants who were actually vaccinated during the 2017/18 influenza season.ConclusionInfluenza vaccine uptake in the active adult population is low in Hungary. Public awareness and knowledge about influenza vaccination and influenza disease should be increased. The results also suggest a need to extend the role played by pharmacists in Hungary.

Knowledge and attitudes towards influenza and influenza vaccination among pregnant women in Kenya

BackgroundInfluenza vaccination during pregnancy benefits mothers and children. Kenya and other low- and middle-income countries have no official influenza vaccination policies to date but are moving towards issuing such policies. Understanding determinants of influenza vaccine uptake during pregnancy in these settings is important to inform policy decisions and vaccination rollout. MethodsWe interviewed a convenience sample of women at antenatal care facilities in four counties (Nairobi, Mombasa, Marsabit, Siaya) in Kenya. We described knowledge and attitudes regarding influenza vaccination and assessed factors associated with willingness to receive influenza vaccine. ResultsWe enrolled 507 pregnant women, median age was 26 years (range 15–43). Almost half (n = 240) had primary or no education. Overall, 369 (72.8%) women had heard of influenza. Among those, 288 (78.1%) believed that a pregnant woman would be protected if vaccinated, 252 (68.3%) thought it was safe to receive a vaccine while pregnant, and 223 (60.4%) believed a baby would be protected if mother was vaccinated. If given opportunity, 309 (83.7%) pregnant women were willing to receive the vaccine. Factors associated with willingness to receive influenza vaccine were mothers’ belief in protective effect (OR 3.87; 95% CI 1.56, 9.59) and safety (OR 5.32; 95% CI 2.35, 12.01) of influenza vaccines during pregnancy. ConclusionApproximately one third of pregnant women interviewed had never heard of influenza. Willingness to receive influenza vaccine was high among women who had heard about influenza. If the Kenyan government recommends influenza vaccine for pregnant women, mitigation of safety concerns and education on the benefits of vaccination could be the most effective strategies to improve vaccine acceptance.

Determinants of influenza vaccination uptake in pregnancy: a large single-Centre cohort study

BackgroundAlthough vaccination of pregnant women against influenza is recommended, the vaccination rate remains low. We conducted a study to identify determinants of influenza vaccination uptake in pregnancy in order to identify strategies to improve seasonal influenza vaccination rates.MethodsProspective observational hospital-based study in the French hospital performing the highest number of deliveries, located in the city of Lille, among all women who had given birth during the 2014–2015 influenza season. Data were collected through a self-completed questionnaire and from medical files. The vaccination uptake was self-reported. Determinants of vaccination uptake were identified using logistic regression analysis.ResultsOf the 2045 women included in the study, 35.5% reported that they had been vaccinated against influenza during their pregnancy. The principal factors significantly associated with greater vaccination uptake were previous influenza vaccination (50.9% vs 20.2%, OR 4.1, 95% CI 3.1–5.5), nulliparity (41.0% vs 31.3%, OR 2.5, 95% CI 1.7–3.7), history of preterm delivery < 34 weeks (43.4% vs 30.3%, OR 2.3, 95% CI 1.1–4.9), the mother’s perception that the frequency of vaccine complications for babies is very low (54.6% vs 20.6%, OR 1.1, 95% CI 0.5–2.2), the mother’s good knowledge of influenza and its vaccine (61.7% vs 24.4%, OR 3.1, 95% CI 2.2–4.4), hospital-based prenatal care in their first trimester of pregnancy (55.0% vs 30.2%, OR 2.1, 95% CI 1.2–3.7), vaccination recommendations during pregnancy by a healthcare worker (47.0% vs 2.7%, OR 18.8, 95% CI 10.0–35.8), receipt of a vaccine reimbursement form (52.4% vs 18.6%, OR 2.0, 95% CI 1.5–2.7), and information from at least one healthcare worker about the vaccine (43.8% vs 19.1%, OR 1.8, 95% CI 1.3–2.6).ConclusionsOur findings suggest that in order to increase flu vaccination compliance among pregnant women, future public health programmes must ensure cost-free access to vaccination, and incorporate education about the risks of influenza and the efficacy/safety of vaccination and clear recommendations from healthcare professionals into routine antenatal care.

Determinants of influenza vaccination uptake among Polish school teachers

Abstract Background School settings place teachers at risk for influenza infection. Polish National Immunization Program recommends influenza vaccination (IV) for this occupational group. The study objective was to assess teachers’ knowledge and attitudes regarding IV, to determine 2018/2019 uptake and factors influencing the IV receipt; this has never been performed before in Central/Eastern Europe. Methods Between March-April 2019 teachers from 5 randomly selected primary schools (2 urban, 3 suburban) in West Pomerania, Poland, were surveyed with the use of the self-administered, anonymous questionnaire. Results Response rate was 50.1%. Among 102 respondents (68.6% females, mean age 45.7 years, mean length of practice 20.3 years), 31.4% were chronically ill. Only 4.9% reported getting the 2018/2019 IV, 8.8% were willing to be vaccinated in the next season. Of the respondents getting the 2018/2019 IV, only one also re-ported getting the 2017/2018 vaccine. The most common source of information about the IV were: family doctor (55.9%) and TV (68.6%). Beliefs that the IV was not effective (40.2%%) and concerns about the side effects (19.6%) were the most common reasons for not getting it. Only 44.1% of respondents believed teachers have heightened risk of contracting influenza. Regarding preventive methods, 83.3% teachers pointed at social distancing, 65.7% - at frequent handwash-ing, 65.7% - at vaccination; 38.2% believed that drinking tea with lemon could prevent influenza. More than a third of teachers (38.4%) thought influenza infection is always symptomatic. Older age was the only factor independently associated with IV receipt (p &amp;lt; 0.05). Conclusions Influenza vaccination coverage among Polish primary school teachers is disturbingly low. Future education strategies encouraging teachers to immunize themselves against influenza should tackle misconceptions about the IV and increase awareness. Interventions related to maximizing IV uptake should focus especially on younger teachers. Key messages This preliminary study showed that influenza vaccination coverage among Polish primary school teachers urgently needs improvement. Teachers should better understand the importance of influenza vaccination as a significant preventive measure and realize their role in infection prevention and transmission at the school setting.

Influenza vaccine uptake in the elderly population: Individual and general practitioner’s determinants in Central Italy, Lazio region, 2016–2017 season

BackgroundElderly people are a priority target group for influenza vaccination and their decision to be vaccinated might partly depend on advice received from general practitioners (GP). This study aims to investigate the association between influenza vaccine uptake in the elderly residents in the Lazio region of Italy and the demographic and professional characteristics of their GPs, taking simultaneously into account the elderly’s individual characteristics. MethodsWe used data retrieved from different administrative sources to retrospectively analyse the cohort of 1,255,657 elderly residents aged ≥65 years who were alive and registered in the regional healthcare service at the beginning of the 2016–2017 influenza vaccination campaign (1 Oct. 2016–31 Jan. 2017). We assessed influenza vaccine uptake at the end of the vaccination campaign and evaluated its association with both individual and GP-related characteristics through a multilevel Poisson regression models accounting for clustering at physician level. ResultsOverall, vaccination coverage at the end of vaccination campaign was 50.6%. Elderly residents who were male, older, vaccinated in the previous seasons, living in smaller provinces, and spending more money for specialist medical care showed a significantly increased probability to be vaccinated. Vaccine uptake was also significantly higher in the elderly residents assisted by GPs who got master’s degree more recently, assisted a relatively high proportion of elderly patients, received influenza vaccination, had a computer assistant, and were associated with other physicians. ConclusionsOur results indicate that influenza vaccination coverage in the elderly residents of the Lazio region is still unsatisfactorily low. We identified several determinants of influenza vaccine uptake, related to both individual and GP characteristics. Understanding how GP characteristics affected influenza vaccine uptake in the elderly population might provide insight on GPs’ attitudes and concerns regarding influenza vaccination, allowing the implementation of targeted evidence-based interventions to sensitise GPs and increase vaccination coverage.

Skewed risk perceptions in pregnant women: the case of influenza vaccination.

BackgroundPregnant women and their newborns have an increased risk of developing severe influenza and influenza-related complications. In Germany, seasonal influenza vaccination is recommended for pregnant women since 2010. However, little is known about pregnant women’s vaccination-related knowledge and attitudes, as well as their risk perceptions. This study therefore assessed pregnant women’s vaccination-related knowledge, risk perceptions related to influenza disease and influenza vaccination during pregnancy, and aimed to identify determinants of influenza vaccination uptake during pregnancy in Germany.MethodsBetween 2012 and 2014, a nationwide web-based prospective cohort study with follow-up interviews was conducted in initially pregnant women who gave birth over the study period. Control groups were set up in a cross-sectional fashion during the follow-up interviews. Women who participated in both, the baseline interview before giving birth and in the 1st interview after giving birth were included in the analysis. Univariate and multiple logistic regression were used to identify associations between influenza vaccination uptake and sociodemographic characteristics as well as items assessing attitude and knowledge.ResultsIn total, 838 women were included in the analyses. Pregnant women had a positive attitude towards vaccination in general, but only modest vaccination knowledge. Overall, 10.9 % of women were vaccinated against seasonal influenza during pregnancy. While pregnant women perceived classical childhood diseases to be more risky than the respective vaccinations, this relation reversed for influenza: The risk of vaccination was perceived higher than the risk of the disease. These two types of risk perceptions independently determined influenza vaccination uptake—higher perception of disease risk and lower perceptions of vaccination-related risks increased uptake. Additionally, knowledge about the vaccination recommendation for pregnant women and a positive gynaecologist’s attitude towards vaccination during pregnancy influenced the uptake significantly.ConclusionsInfluenza vaccination uptake in pregnant women is low in Germany. Tailored communication strategies for pregnant women should focus especially on changing the perceptions of personal risks regarding influenza and influenza vaccination during pregnancy. Gynaecologists should be made aware about their crucial role in supporting vaccination decision-making of pregnant women and the need to provide relevant information to counteract misconceptions.

Understanding factors influencing vaccination acceptance during pregnancy globally: A literature review

Maternal vaccination has been evaluated and found to be extremely effective at preventing illness in pregnant women and new-borns; however, uptake of such programmes has been low in some areas.To analyse factors contributing to uptake of vaccines globally, a systematic review on vaccine hesitancy was carried out by The Vaccine Confidence Project in 2012. In order to further analyse factors contributing to uptake of maternal immunisation, a further search within the broader systematic review was conducted using the terms ‘Pregnan*’ or ‘Matern*’. Forty-two articles were identified. Pregnancy-related articles were further screened to identify those focused on concerns, trust and access issues regarding maternal vaccination reported by pregnant women and healthcare workers. Thirty-five relevant articles were included which were then searched using the snowballing technique to identify additional relevant references cited in these articles. A search alert was also conducted from February to April 2015 in PubMed to ensure that no new relevant articles were missed. A total of 155 relevant articles were included.Most of the literature which was identified on hesitancy surrounding vaccination during pregnancy reports on determinants of influenza vaccine uptake in North America. Research conducted in low-income countries focused primarily on tetanus vaccine acceptance. The main barriers cited were related to vaccine safety, belief that vaccine not needed or effective, not recommended by healthcare worker, low knowledge about vaacines, access issues, cost, conflicting advice. From the point of view of healthcare workers, barriers included inadequate training, inadequate reimbursement and increased workload. Twenty-seven out of 46 (59%) articles mentioning ethnicity reported lower rates of coverage among ethnic minorities.Barriers to vaccination in pregnancy are complex and vary depending on context and population. There are wide gaps in knowledge regarding the attitudes of healthcare workers and how ethnicity and gender dynamics influence a pregnant woman's decision to vaccinate.

Influenza vaccination coverage rates among adults before and after the 2009 influenza pandemic and the reasons for non-vaccination in Beijing, China: A cross-sectional study

BackgroundTo optimize the vaccination coverage rates in the general population, the status of coverage rates and the reasons for non-vaccination need to be understood. Therefore, the objective of this study was to assess the changes in influenza vaccination coverage rates in the general population before and after the 2009 influenza pandemic (2008/2009, 2009/2010, and 2010/2011 seasons), and to determine the reasons for non-vaccination.MethodsIn January 2011 we conducted a multi-stage sampling, retrospective, cross-sectional survey of individuals in Beijing who were ≥ 18 years of age using self-administered, anonymous questionnaires. The questionnaire consisted of three sections: demographics (gender, age, educational level, and residential district name); history of influenza vaccination in the 2008/2009, 2009/2010, and 2010/2011 seasons; and reasons for non-vaccination in all three seasons. The main outcome was the vaccination coverage rate and vaccination frequency. Differences among the subgroups were tested using a Pearson’s chi-square test. Multivariate logistic regression was used to determine possible determinants of influenza vaccination uptake.ResultsA total of 13002 respondents completed the questionnaires. The vaccination coverage rates were 16.9% in 2008/2009, 21.8% in 2009/2010, and 16.7% in 2010/2011. Compared to 2008/2009 and 2010/2011, the higher rate in 2009/2010 was statistically significant (χ2=138.96, p<0.001), and no significant difference existed between 2008/2009 and 2010/2011 (χ2=1.296, p=0.255). Overall, 9.4% of the respondents received vaccinations in all three seasons, whereas 70% of the respondents did not get a vaccination during the same period. Based on multivariate analysis, older age and higher level of education were independently associated with increased odds of reporting vaccination in 2009/2010 and 2010/2011. Among participants who reported no influenza vaccinations over the previous three seasons, the most commonly reported reason for non-vaccination was ‘I don’t think I am very likely to catch the flu’ (49.3%).ConclusionsWithin the general population of Beijing the vaccination coverage rates were relatively low and did not change significantly after the influenza pandemic. The perception of not expecting to contract influenza was the predominant barrier to influenza vaccination. Further measures are needed to improve influenza vaccination coverage.

Determinants of influenza vaccination uptake among Italian healthcare workers

We analyzed seasonal influenza vaccination coverage among the Italian healthcare workers (HCW) in order to identify socio-demographic and clinical determinants of vaccination. We used data from the survey “Health and health care use in Italy,” which comprised interviews of 5,336 HCWs For each respondent, information on socioeconomic, health conditions, self-perceived health and smoking status were obtained. After bivariate analysis, we used multilevel regression models to assess determinants of immunization. Overall 20.8% of HCWs (95%CI 19.7–21.9) reported being vaccinated against seasonal influenza. After controlling for potential confounders, multilevel regression revealed that older workers have a higher likelihood of vaccine uptake (OR = 6.07; 95% CI 4.72–7.79). Conversely, higher education was associated with lower vaccine uptake (OR = 0.65; 95% IC 0.50–0.83). Those suffering from diabetes (OR = 2.07; 95% CI 1.19–1.69), COPD (OR = 1.95; 95% CI 1.31–2.89) and cardiovascular diseases (OR = 1.48 95% CI 1.11–1.96) were more likely to be vaccinated. Likewise, smokers, or former smokers receive more frequently the vaccination (OR = 1.40; 95% CI 1.15–1.70; OR = 1.54; 95% CI 1.24–1.91, respectively) compared with never-smokers as well as those HCWs reporting fair or poor perceived health status (ORs of 1.68, 95% CI 1.30–2.18). Vaccine coverage among HCWs in Italy remains low, especially among those with no comorbidities and being younger than 44 y old. This behavior not only raises questions regarding healthcare organization, infection control in healthcare settings and clinical costs, but also brings up ethical issues concerning physicians who seem not to be very concerned about the impact of the flu on themselves, as well as on their patients. Influenza vaccination campaigns will only be effective if HCWs understand their role in influenza transmission and prevention, and realize the importance of vaccination as a preventive measure