Influenza vaccination rates in children decline when the live attenuated influenza vaccine is not recommended

BackgroundIn 2016 the Centers for Disease Control and Prevention (CDC) recommended against using the live attenuated influenza vaccine (LAIV) for the 2016–2017 influenza season. This recommendation is potentially important for vaccination rates because perceived effectiveness and ease of administration are among the primary determinants of families decisions to vaccinate their children. This investigation sought to determine whether rates of pediatric influenza vaccination changed in a season when the LAIV was not recommended.MethodsThis study used cohort and cross sectional data from an academic primary care pediatric center in central Pennsylvania that serves approximately 12,500 patients. Early season (prior to November 1) and end-of-season (prior to March 1) vaccination rates in the 2015–16 and 2016–17 influenza seasons were recorded for individuals 2–17 years old. Repeat vaccination rates (percentage of children receiving influenza vaccination in one season who were also vaccinated in the next season) were recorded for the 2015–16 into 2016–17 seasons. A logistic regression model adjusting for race, ethnicity, age, insurance type and type of vaccination received was employed to identify predictors of repeat vaccination.ResultsIn the absence of LAIV (2016–17) early vaccination rates were significantly higher (24.7% vs 22.8%, p = 0.004), but end-of-season rates were lower (50.4% vs 52.0%, p = 0.03) than when LAIV was offered (2015–16). After adjusting for covariates, those who had received IIV in the 2015–16 season had higher odds (OR 1.32, 95% CI, 1.15–1.52) of getting a repeat vaccination in the 2016–17 season, compared with those who had received LAIV in the 2015–16 season.ConclusionsEnd-of-season vaccination rates were lower in 2016–17 when LAIV was not recommended, particularly among children who received LAIV in the preceding year. Unavailability of LAIV in the 2016–17 season may have impacted influenza vaccination convenience and perceived effectiveness, two factors which could influence vaccine uptake in pediatric populations.     

Parental perceptions of childhood seasonal influenza vaccination in Singapore: A cross-sectional survey

PurposeSeasonal influenza vaccination is recommended in children aged 6–59 months, but little is known about child vaccination coverage and determinants in Asian settings. We report the results of a survey of knowledge, attitudes, practices, and determinants of child influenza vaccination in Singapore.MethodsIn December 2015-March 2016, we conducted a survey of 332 parents of children aged 6 months to 5 years attending pre-schools. We assessed child influenza vaccine coverage and parental knowledge, attitudes, and practices of child influenza vaccination. We used multivariable regression and structural equation models to identify factors associated with child influenza vaccination.ResultsKnowledge about influenza, perceived benefit of vaccination, and willingness to vaccinate were high. However, only 32% of children had ever received influenza vaccine, and only 15% in the past year. Factors independently associated with child influenza vaccination included: being recommended influenza vaccine by a child’s doctor (prevalence ratio (PR) = 2.47, 95% CI: 1.75–3.48); receiving influenza vaccine information from a private general practitioner (PR = 1.47, 95% CI: 1.05–2.04); regularly receiving pre-travel influenza vaccine (PR = 1.64, 95% CI: 1.19–2.25); higher willingness to vaccinate (PR = 1.58, 95% CI:1.24–2.04 per unit increase in willingness score); and feeling well-informed about influenza vaccine (PR = 1.44, 95% CI: 1.04–1.99). Parents who obtained influenza vaccine information from television were less likely to have vaccinated their child (PR = 0.44, 95% CI: 0.23–0.85). Path analysis indicated that being recommended vaccination by a child's doctor increased willingness to vaccinate and self-efficacy (feeling well-informed about influenza vaccine). Median willingness-to-pay for a dose of influenza vaccine was SGD30 (interquartile range: SGD20-SGD50), and was higher in parents of vaccinated compared with unvaccinated children (SGD45 vs SGD30, p = 0.0012).ConclusionKnowledge and willingness to vaccinate was high in this parent population, but influenza vaccine uptake in children was low. Encouraging medical professionals to recommend vaccination of eligible children is key to improving uptake.     

Variability in influenza vaccination opportunities and coverage among privately insured children

BackgroundUniversal influenza vaccination has been recommended since 2010, yet influenza vaccination rates among children aged 6 months to 17 years remain low compared with other routinely recommended childhood vaccines.ObjectiveAssess in-plan vaccination coverage, opportunities, and missed opportunities during the 2016–2017 influenza season.Study Design:Retrospective analyses using 2016–2017 MarketScan® data for 2,768,799 privately insured children aged 1–17 years by the end of 2016 who were continuously enrolled in the same insurance plan during the 2016–2017 influenza season (defined as August 1, 2016 through May 31, 2017). We assessed in-plan vaccination coverage (percentage receiving ≥ 1 dose of influenza vaccine from August 2016-May 2017) and vaccination opportunities (percentage with ≥ 1 provider visit between September 2016 – May 2017). Among children who remained unvaccinated at the end of the season, those with ≥ 1 influenza vaccination opportunity between September 2016-May 2017 were determined to have a missed opportunity.ResultsIn-plan vaccination coverage during the 2016–17 season was 67.7% in infants (born 2015), 49.5% in toddlers (born 2012–2014), 35.0% in school-aged children (born 2004–2011), and 22.3% in teenagers (born 1999–2003). Like vaccination coverage, vaccination opportunities decreased with age (infants: 97.7%, toddlers: 91.9%, school-aged children: 82.6%, teenagers: 79.3%). Among unvaccinated children, 93.1%, 84.1%, 73.6% and 73.6% of each age group had a missed opportunity for influenza vaccination.ConclusionOpportunities for and coverage with influenza vaccination vary even among privately insured children. Along with continued efforts to reduce missed opportunities, effective strategies to bring children to their doctor for annual influenza vaccination are needed, particularly for older children.     

Lineage-matched versus mismatched influenza B vaccine effectiveness following seasons of marginal influenza B circulation

BackgroundSeveral countries have recently transitioned from the trivalent inactivated influenza vaccine (TIV) to the quadrivalent inactivated influenza vaccine (QIV) in order to outweigh influenza B vaccine-mismatch. However, few studies thus far evaluated its benefits versus the TIV in a systematic manner. Our objective was to compare the QIV VE with lineage-mismatched TIV VE.MethodsWe estimated the 2015–2016, 2017–2018, 2019–2020 end-of season influenza B VE against laboratory-confirmed influenza-like illness (ILI) among community patients, using the test-negative design. VE was estimated for pre-determined age groups and for moving age intervals of 15 years.ResultsSince 2011–2012 season, alternate seasons in Israel were dominated by influenza B circulation. Compared with the lineage-mismatched TIV used during the 2015–2016 and 2017–2018 seasons, the 2019–2020 QIV showed the highest all-ages VE, with VE estimates of 56.9 (95% CI 30.1 to 73.4), 16.5 (95% CI –22.5 to 43.1) and ?25.8 (95% CI ?85.3 to 14.6) for the 2019–2020, 2017–2018 and 2015–2016 seasons, respectively. The 2019–2020 VE point estimated were the highest for the 0.5–4, 5–17 and 18–44 years age groups and for more 15-year age intervals as compared to the other seasons.ConclusionsOur results support the rapid transition from the TIV to the QIV.     

Inactivated influenza vaccine effectiveness and an analysis of repeated vaccination for children during the 2016/17 season

ObjectivesWe assessed the vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) in children 6 months to 15 years of age during the 2016/17 season. In addition, we estimated the impact of repeated vaccination in children on VE.MethodsOur study for VEs in preventing influenza and admission due to influenza were conducted according to a test-negative case-control design (TNCC) based on influenza rapid diagnostic test results. We also analyzed the VE by vaccine status in the current and previous seasons for the impact of repeated vaccination.ResultsDuring the 2016/17 season, the quadrivalent IIV was used in Japan. The adjusted VE in preventing influenza illness was 38% (95% CI, 29–46) against influenza A and 39% (95% CI, 18–54) against influenza B. Infants showed no significant VE. The VE in preventing hospitalization was not demonstrated. For the analysis of repeated vaccination, the vaccine was effective only when immunization occurred in the current season. The children who were immunized in two consecutive seasons were more likely to develop influenza compared to those immunized in the current season only (odds ratio, 1.58 [95% CI, 1.05–2.38], adjusted odds ratio, 1.53 [95% CI, 0.99–2.35]). However, the odds ratio of repeated vaccination was not significant when the analysis excluded those who developed influenza in the previous season.ConclusionsVE in children in the 2016/17 season was similar to values previously reported. Repeated vaccination interfered with the VE against any influenza infection in the 2016/17 season. The results of our study suggest that decreased VE by repeat vaccination phenomenon was associated with immunity by influenza infection in the previous season. However, the influenza vaccine should be recommended every season for children.     

Trends in compliance with two-dose influenza vaccine recommendations in children aged 6 months through 8 years, 2010–2015

BackgroundChildren aged 6 months through 8 years may require two doses of influenza vaccine for adequate immune response against the disease. However, poor two-dose compliance has been reported in the literature.MethodsWe analyzed data for >2.6 million children from six immunization information system (IIS) sentinel sites, and assessed full vaccination coverage and two-dose compliance in the 2010–2015 influenza vaccination seasons. Full vaccination was defined as having received at least the recommended number of influenza vaccine doses (one or two), based on recommendations from the Advisory Committee on Immunization Practices. Two-dose compliance was defined as the percentage of children during each season who received at least two doses of influenza vaccine among those who required two doses and initiated the series.ResultsAcross seasons, ⩾1-dose influenza vaccination coverage was mainly unchanged among 6–23 month olds (range: 60.9–66.6%), 2–4 year olds (range: 44.8–47.4%), and 5–8 year olds (range: 34.5–38.9%). However, full vaccination coverage showed increasing trends from 2010–11 season to 2014–15 season (6–23 months: 43.0–46.5%; 2–4 year olds: 26.3–39.7%; 5–8 year olds, 18.5–33.9%). Across seasons, two-dose compliance remained modest in children 6–23 months (range: 63.3–67.6%) and very low in older children (range: 11.6–18.7% in children 2–4 years and 6.8–13.3% in children 5–8 years). In the 2014–15 season, among children who required and received 2 doses, only half completed the two-dose series before influenza activity peaked.ConclusionsImproved messaging of the two-dose influenza vaccine recommendations is needed for providers and parents. Providers are encouraged to determine a child’s eligibility for two doses of influenza vaccine using the child’s vaccination history, and to vaccinate children early in the season so that two-dose series are completed before influenza peaks.     

A multi-country investigation of influenza vaccine coverage in pregnant individuals, 2010–2016

BackgroundMany countries recommend influenza vaccination during pregnancy. Despite this recommendation, influenza vaccine among pregnant individuals remains under-utilized and uptake varies by country. Factors associated with influenza vaccine uptake during pregnancy may also vary across countries.MethodsAs members of the Pregnancy Influenza Vaccine Effectiveness Network (PREVENT), five sites from four countries (Australia, Canada, Israel, and the United States) retrospectively identified cohorts of individuals aged 18–50 years who were pregnant during pre-defined influenza seasons. Influenza vaccine coverage estimates were calculated for the 2010–11 through 2015–16 northern hemisphere and the 2012 through 2015 southern hemisphere influenza seasons, by site. Sites used electronic health records, administrative data, and immunization registries to collect information on pregnancy, health history, demographics, and vaccination status. Each season, vaccination coverage was calculated as the percentage of individuals who received influenza vaccine among the individuals in the cohort that season. Characteristics were compared between those vaccinated and unvaccinated, by site.ResultsMore than two million pregnancies were identified over the study period. Influenza vaccination coverage ranged from 5% to 58% across sites and seasons. Coverage increased consistently over the study period at three of the five sites (Western Australia, Alberta, and Israel), and was highest in all seasons at the United States study site (39–58%). Associations with vaccination varied by country and across seasons; where available, parity >0, presence of a high-risk medical condition, and urban residence were consistently associated with increased likelihood of vaccination.ConclusionsThough increasing, uptake of influenza vaccine among pregnant individuals remains lower than recommended. Coverage varied substantially by country, suggesting an ongoing need for targeted strategies to improve influenza vaccine uptake in this population.     

Using classification and regression tree analysis to explore parental influenza vaccine decisions

Background and objectivesInfluenza poses a public health threat for children and adults. The CDC recommends annual influenza vaccination for children <18 years, yet vaccine uptake remains low for children (57.9%) and adults (37.1%). Given that parental decision-making is key in childhood vaccine uptake, there is a critical need to understand vaccine hesitancy among parents who decide not to vaccinate their children. This study aims to explore predictors of children’s influenza vaccine status given parental vaccination status and examine the factors that contribute to concordance or discordance between parental and children’s vaccine uptake.MethodsClassification and regression tree (CART) analyses were used to identify drivers of parental decisions to vaccinate their children against influenza. Hierarchy and interactions of these variables in predicting children’s vaccination status were explored.ResultsFrom a nationally representative sample of non-Hispanic Black and White parents who completed an online survey (n = 328), the main factors influencing parents’ decisions to vaccinate their children were vaccine behavior following physician recommendation, knowledge of influenza recommendations for children, influenza vaccine confidence and disease risk. Among unvaccinated parents, the greatest concordance was observed among parents who usually do not get vaccinated following physician recommendation and had lower knowledge of recommendations for influenza vaccination for children. The greatest discordance was observed among unvaccinated parents who had lower hesitancy about recommended vaccines.ConclusionsUnderstanding drivers of parental decisions to vaccinate themselves and their children can provide insights on health communication and provider approaches to increase influenza vaccine coverage and prevent influenza related mortality.     

Vaccine decision-making begins in pregnancy: Correlation between vaccine concerns,intentions and maternal vaccination with subsequent childhood vaccine uptake

IntroductionMaternal and childhood vaccine decision-making begins prenatally. Amongst pregnant Australian women we aimed to ascertain vaccine information received, maternal immunisation uptake and attitudes and concerns regarding childhood vaccination. We also aimed to determine any correlation between a) intentions and concerns regarding childhood vaccination, (b) concerns about pregnancy vaccination, (c) socioeconomic status (SES) and (d) uptake of influenza and pertussis vaccines during pregnancy and routine vaccines during childhood.MethodsWomen attending public antenatal clinics were recruited in three Australian states. Surveys were completed on iPads. Follow-up phone surveys were done three to six months post delivery, and infant vaccination status obtained via the Australian Childhood Immunisation Register (ACIR).ResultsBetween October 2015 and March 2016, 975 (82%) of 1184 mothers consented and 406 (42%) agreed to a follow up survey, post delivery. First-time mothers (445; 49%) had significantly more vaccine concerns in pregnancy and only 73% had made a decision about childhood vaccination compared to 89% of mothers with existing children (p-value < 0.001). 66% of mothers reported receiving enough information during pregnancy on childhood vaccination. In the post delivery survey, 46% and 82% of mothers reported receiving pregnancy influenza and pertussis vaccines respectively. The mother's degree of vaccine hesitancy and two attitudinal factors were correlated with vaccine uptake post delivery. There was no association between reported maternal vaccine uptake or SES and childhood vaccine uptake.ConclusionFirst time mothers are more vaccine hesitant and undecided about childhood vaccination, and only two thirds of all mothers believed they received enough information during pregnancy. New interventions to improve both education and communication on childhood and maternal vaccines, delivered by midwives and obstetricians in the Australian public hospital system, may reduce vaccine hesitancy for all mothers in pregnancy and post delivery, particularly first-time mothers.     

Why do parents not re-vaccinate their child for influenza? A prospective cohort study

Child influenza vaccination rates for the UK are published annually, however there are no publicly available data on how many children are re-vaccinated the following year. This prospective cohort study aimed to identify factors associated with not re-vaccinating one’s child. Participants (n = 270) completed a questionnaire before their child was vaccinated for influenza in the 2016/17 season, and follow-up questionnaires three days and one month after their child’s vaccination. Re-vaccination data were collected at the end of the 2017/18 influenza season (n = 232, response rate 85.9%). Forty-one children (17.7%) were not re-vaccinated for influenza in 2017/18. Parental report of severe side-effects three days after vaccination (p = .04) and worry about side-effects one month after vaccination (p = .05) were associated with not re-vaccinating. However, the restricted sample size reduced the statistical power of these analyses. Decreasing parental worry about side-effects may help improve re-vaccination rates.Clinical trial registration: The study was registered on ClinicalTrials.gov (NCT02909855).     

Uptake of funded influenza vaccines in young Australian children in 2018; parental characteristics,information seeking and attitudes

ObjectiveInfants and children under 5-years are at an increased risk of complications from influenza. We aimed to evaluate characteristics associated with uptake of Australian state and territory funded influenza vaccine programs in 2018 for children aged 6-months to 5-years.Materials and methodsA national online survey of 1002 Australian parents with at least one child aged between 6-months and 5-years (response rate 29.9%). A 23-item online questionnaire asked parents about health service use, 2017 and 2018 influenza vaccine uptake, and routine childhood vaccine status for their youngest child. Parents were also asked a range of questions about their demographics, sources of vaccine information, and beliefs and attitudes towards immunisation.ResultsA total of 1002 parents completed the questionnaire and 52.9% of children aged 6-months to 5-years in our sample were immunised against influenza in 2018; representing a significant increase from 2017. Knowing the vaccine was free for their child, and being influenced by a pharmacist increased the likelihood that their child received the influenza vaccine. Not receiving an influenza vaccine recommendation from a health care provider significantly reduced the likelihood of immunisation. Some parents were worried about the safety of the influenza vaccine for their child (36.4%), while 26.5% of parents agreed that you can catch influenza from the vaccine.ConclusionsUptake of influenza vaccine for Australian children aged 6-months to 5-years increased significantly in 2018. Continuing efforts to build parents’ trust in childhood influenza vaccination are still required. Increasing opportunities for health care providers to recommend vaccination will lead to further improvements in uptake for young children.     

Increasing healthcare workers’ uptake of seasonal influenza vaccination in a tertiary-care pediatric hospital in Greece with a low-cost,tailor-made,multifaceted strategy

BackgroundHealthcare workers’ (HCW) seasonal influenza vaccination (SIV) is critical to prevent nosocomial influenza. However, HCW vaccination rates remain unacceptably low in many European institutions. A two-year three-step initiative was implemented at a tertiary-care pediatric hospital with 750 beds in Athens, Greece with the aim of increasing SIV among HCW.MethodsΑ cross-sectional anonymous survey of HCWs was conducted during the 2015–16 influenza season with the aim to evaluate attitudes, knowledge, and specific barriers and facilitators for SIV. Stratified analysis was used to identify factors associated with no prior history of influenza vaccination. Multifaceted interventions were implemented in the 2016–2017 season. These included 1) education around influenza disease and SIV, and 2) communication of availability and opportunity (time and place) of SIV. Interventions were designed to target HCWs with the lowest SIV rates in the previous three years.ResultsWe achieved a 67% response rate, with 363 respondents (106 doctors, 145 nurses, 101 other hospital staff; 11 did not provide their profession). Most (64%) had not been vaccinated in the previous three years; only 14% received the vaccine annually. Non-vaccination rates were significantly higher among nurses (76%) and cleaning and food-service workers (73%) compared to doctors (40%) (P < 0.001). Protection of self, family, patients and colleagues were the most common motivations. Concerns about the safety and effectiveness of the vaccine, the belief that one does not belong to a high-risk group were the most common barriers. The interventions led to an increase in SIV uptake by the HCWs in the hospital, from 19% to 31%.ConclusionsIn a country with very low reported rates of vaccination among HCWs, a simple, low-cost, tailor-made intervention strategy can lead to an increase in SIV uptake. Stratifying data according to vaccination history may reveal a diversity of targets for improvement that might otherwise be missed.     

“You Have to Die Not to Come to Work”: A Mixed Methods Study of Attitudes and Behaviors regarding Presenteeism,Absenteeism and Influenza Vaccination among Healthcare Personnel with Respiratory Illness in Israel, 2016–2019

IntroductionHealthcare personnel (HCP) have an increased risk of exposure to influenza and other respiratory pathogens. Increased presenteeism, decreased absenteeism, and low uptake of the influenza vaccine can contribute to the spread of influenza among HCP in healthcare settings. We used a mixed methods approach to investigate attitudes and behaviors of HCP in Israel towards influenza vaccination, presenteeism, and absenteeism.MethodsThe study took place over three influenza seasons (2016–2017, 2017–2018, 2018–2019) at the largest hospital in southern Israel. We administered a Knowledge, Attitudes and Practices (KAP) questionnaire and conducted semi-structured interviews with HCP who had been recently ill with respiratory symptoms. The KAP questionnaire included closed-ended questions about attitudes and behaviors regarding influenza, working while sick, and influenza vaccination. The interviews investigated HCP’s perceptions of influenza infection and attitudes about absenteeism, presenteeism, and the influenza vaccine.ResultsWe conducted 74 semi-structured interviews over three influenza seasons. Four HCP were interviewed twice, in separate seasons for different illness episodes. The 70 individuals interviewed included 16 physicians, 45 nurses or technicians, and 9 administrative staff. The median age was 42.5 years (range: 25–60), and most (79%) were female. Half (50%) got vaccinated against influenza before their illness episode. In interviews, most HCP said they come to work while sick (presenteeism) due to a strong personal work ethic and an institutional culture that discourages taking sick leave (absenteeism). HCP expressed skepticism about the effectiveness of the influenza vaccine as well as concern that the influenza vaccine causes severe illness.DiscussionOver three influenza seasons in Israel, HCP cited a number of reasons for working while sick, and doubted the usefulness of influenza vaccine. Addressing reasons for presenteeism and vaccine hesitancy among HCP is crucial to protect HCP and patients from influenza virus infection and other viral respiratory illnesses, such as COVID-19.     

The Health Belief Model in predicting healthcare workers' intention for influenza vaccine uptake in Jordan

BackgroundTheories of health behavior change are being inadequately adopted to understand the reasons behind low influenza vaccination rates among healthcare workers (HCWs). The Theory of Planned Behavior (TPB) is being used to predict intention-behavior relationship while the Health Belief Model (HBM) is being employed to predict actual behavior. The purpose of this study was to test a conceptual model based on the HBM’s constructs to predict Jordanian HCWs’ intentions for influenza vaccine uptake as an alternative to the TPB.MethodA cross-sectional questionnaire-based study was conducted in 2016 in a tertiary teaching hospital in Amman-Jordan including a convenience sample of 477 HCWs with direct patient contact. The study instrument was tested for validity and reliability. A conceptual regression model was proposed incorporating the constructs of the primary HBM with some modifications in the threat construct as well as an additional variable about explicit past vaccination behavior (in the past year and/or any previous history of influenza vaccine uptake).ResultsAlmost all the constructs of the HBM demonstrated significant differences between participants intending and those who did not intend to vaccinate against influenza. After adjusting for the confounding variables in the final conceptual regression model, past vaccination behavior (OR= 4.50, 95%Confidence Interval 3.38–6.00, P< 0.0005) and the perceived benefit scale (OR= 1.19, 95% Confidence Interval 1.11–1.28, P< 0.0005) were the only significant predictors of intentions to vaccinate against influenza in the next season.ConclusionTaking into consideration the altruistic beliefs of HCWs and their explicit past vaccination history augments the utility of the original HBM tool in predicting HCWs’ intentions to vaccinate against influenza in a way that is consistent with the predictive ability of the Theory of Planned Behavior.     

Self-reported prenatal influenza vaccination and early childhood vaccine series completion

BackgroundNo studies have examined associations between prenatal vaccination and childhood vaccination. Mothers who refuse influenza vaccinations during pregnancy report similar attitudes and beliefs to those who refuse vaccinations for their children. The objective of this study was to examine the association between self-reported prenatal influenza vaccination and early childhood vaccination.MethodsA retrospective cohort study was conducted with existing surveillance data from 4022 mothers who responded to the 2009–2011 Minnesota Pregnancy Risk Assessment Monitoring System survey and child vaccination records from the Minnesota Immunization Information Connection database. The childhood vaccine series outcome included the following vaccines: diphtheria, tetanus, and pertussis; poliovirus; measles, mumps, and rubella; Haemophilus influenzae type b (Hib); hepatitis B; varicella; and pneumococcal conjugate. To evaluate the association between self-reported prenatal influenza vaccination and early childhood vaccination, unadjusted and adjusted logistic regression was used to estimate log odds for childhood vaccination status, while margins post-estimation commands were used to obtain predicted probabilities and risk differences.ResultsVaccine series completion was 10.86% higher (95% confidence interval (CI) 7.33%–14.40%, adjusted and weighted model) in children of mothers who had a prenatal influenza vaccine compared to those who did not. For individual vaccines in the recommended series, risk differences ranged from 7.83% (95% CI 5.37%, 10.30%) for the Hib vaccine to 10.06% (95% CI 7.29%, 12.83%) for the hepatitis B vaccine.ConclusionSelf-reported prenatal influenza vaccination was associated with increased early childhood vaccination. More research is needed to confirm these results and identify potential intervention strategies.     

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.     

Comparative effectiveness of high dose versus adjuvanted influenza vaccine: A retrospective cohort study

BackgroundAdults 65 years and older (seniors) experience more complications following influenza infection than younger adults. We estimated the relative vaccine effectiveness (rVE) of a trivalent high dose (HD-IIV3) versus an adjuvanted trivalent influenza vaccine (aIIV3) in seniors for respiratory-related hospitalizations.MethodsWe conducted a retrospective cohort study using claims data from Optum’s Clinformatics® Data Mart to compare outcome rates between seniors who received HD-IIV3 versus aIIV3 during the 2016/17 and 2017/18, predominantly A/H3N2 respiratory seasons. Rates were adjusted for demographic characteristics, comorbid conditions, previous influenza vaccination, and geography. We used the previous event rate ratio (PERR) approach to address bias by time-fixed unmeasured confounders.ResultsWe identified 842,282 HD-IIV3 and 34,157 aIIV3 recipients for the 2016/17 season and 1,058,638 HD-IIV3 and 189,636 aIIV3 recipients for the 2017/18 season. The pooled rVE of HD-IIV3 versus aIIV3 for respiratory-related hospitalizations over both seasons was 12% (95% confidence interval: 3.3%–20%); 13% (−6.4% to 32%) for the 2016/17 season and 12% (2.1%–21%) for the 2017/18 season.ConclusionsPooled over two predominantly A/H3N2 respiratory seasons, HD-IIV3 was associated with fewer respiratory hospital admissions than aIIV3 in senior members of large national managed health care company in the U.S.     

An assessment of parental knowledge,attitudes, and beliefs regarding influenza vaccination

IntroductionSeasonal influenza imposes a significant clinical and economic burden. Despite the availability of an annual vaccine to prevent influenza infection and reduce disease severity, influenza vaccination rates remain suboptimal. Research suggests personal experience, perceived effectiveness, and concerns regarding vaccine safety and side effects are the most influential factors in predicting a parent’s decision to vaccinate. However, current literature is primarily focused on the vaccine decision-making of healthcare workers and those at high risk for influenza complications.MethodsTo assess parental attitudes and beliefs regarding the influenza vaccine, a brief mixed-methods survey was developed and optimized for an electronic platform. The Health Belief Model informed survey design and data analysis. Questions were classified into five core concepts: knowledge, barriers, benefits, experience, and severity. Participants were solicited from a population of parents whose children had participated in a school-based influenza surveillance study (n = 244, 73% response rate). We tested associations between responses and children’s influenza vaccination status the prior season. Categorical questions were tested using Pearson's chi-squared tests and numerical or ordered questions using Mann-Whitney tests. P-values were corrected using the Bonferroni method.ResultsDoubting effectiveness, concerns about side effects, inconvenience, and believing the vaccine is unnecessary were barriers negatively associated with parents’ decision to vaccinate their children during the 2017–18 flu season (p < 0.001). Knowledge that the vaccine is effective in lowering risk, duration, and severity of influenza; receiving the influenza vaccine as an adult; and recognizing the importance of vaccination to prevent influenza transmission in high-risk populations were positively associated with parents’ decision to vaccinate (p < 0.001).ConclusionUnderstanding barriers and motivators behind parents’ decision to vaccinate provides valuable insight that has the potential to shape vaccine messaging, recommendations, and policy. The motivation to vaccinate to prevent influenza transmission in high-risk populations is a novel finding that warrants further investigation.